Fitness & Health with Dr. Gabe Mirkin

Most Running Shoes Slow You Down and Increase Risk of Injuries

2013-03-26T20:14:00.000-04:00

Research presented at the Annual Meeting of the American Academy of Orthopedic Surgeons (March 19, 2013) and to be published next month (Journal of Strength & Conditioning Research, April 2013) shows that running shoes with thick heels can slow you down. They may also increase your chances of injuring yourself.

Adolescent competitive track athletes ran on a treadmill in heavily padded-at-the-heel sneakers, track shoes or barefoot, at four different speeds.

CHANGING FOOTWEAR CHANGES LANDING: Wearing cushioned heel sneakers caused the runners to land on their heel 70 percent of the time at all speeds. Wearing track shoes caused them to land on their heels less than 35 percent of the time. Running barefoot, they landed on their heels less than 30 percent of the time. Shoes with cushioned heels caused runners to land on their heels, while wearing track shoes or no shoes at all caused a forefoot or mid-foot landing.

HARM FROM HEEL STRIKE: Barefoot runners tend to land on their mid-foot or forefoot. Cushioned heels on running shoes tempt runners to take longer strides, so they land on their heels and smack the ground with a much greater force.

Landing on your heel causes the force of your heel striking the ground to be transmitted with more direct and greater force to your hips and knees. Running in flat-soled shoes that promote a forefoot strike transmits less foot-strike force up your leg to your back and helps to prevent hip and knee damage.

One study reports that running barefoot, in and of itself, is neither good nor bad. The key is to decrease the force of your foot hitting the ground. Running barefoot encourages you to take a shorter stride and hit the ground with less force (Journal of Strength and Conditioning Research, 2012; 26 (8): 2021).

WHY RUNNERS ARE INJURED SO FREQUENTLY: Harvard University evolutionary biologist Dan Lieberman claims that modern running shoes may explain why fifty percent of serious runners are injured at least once a year. He also believes that people with joint replacements of their lower extremities should not run (Nature, January, 2010).

LANDING ON YOUR HEELS: Modern running shoes have features that cause runners to land on their heels with forces of at least three times body weight at six-minute mile pace. The faster a runner runs, the greater the force, which causes stress fractures of the feet and lower legs, shin splints, tears in the fascia on the bottom of the feet, knee and hip pain, tendon and joint damage and more.

LANDING ON YOUR FOREFOOT: Hitting the ground with the heel first generates tremendous force because it stops the foot suddenly and temporarily. On the other hand, landing on the front of the foot allows the foot to keep on moving as the heel is lowered toward the ground to distribute the forces throughout the entire lower leg. For example, drop a pen on the tip of one end. It hits with tremendous force because it stops when it hits the ground and then falls forward. However if the pen were dropped on the side of one end, it would hit the ground with much less force because after hitting on the side of one end, the force would be distributed as the pen falls backward to the other end.

EXCESSIVE PRONATION: In the 1960s doctors thought that the high frequency of running injuries was caused by excessive pronation, a rolling inward of the foot after the heel strikes the ground. They felt that the foot rolled inward toward the arch to dissipate the tremendous heel strike forces.

This, in turn, caused the lower leg to twist inward and they blamed the frequent running injuries on the inward twisting motion of the leg after heel strike. They invented running shoes with special arch supports called orthotics to limit inward rolling and built running shoes with thick heels to cushion some of the shock of the heel hitting the ground. These features increase the likelihood that runners land on their heels. Today the standard treatment for many running injuries is special orthotics and padded heels to help heal running injuries. I have written about and prescribed these features for many of my patients with running injuries.

LESS FORCE WITH FOREFOOT LANDING: Dr. Lieberman felt that if the runners ran barefoot, they would be less likely to land on their heels and therefore would not need to wear shoes with padded heels and orthotics. He has shown in elegant experiments that landing on the front part of the foot reduces the force of the foot strike very significantly.

However, he has no data to show that running injuries can be prevented by running barefoot. He has shown only that modern running shoes tend to encourage a runner to land on his heels, and that heel strike generates more force than front foot strike. Also, many roads have stones and cut glass that can cause injuries, and most runners have such thin skin on the bottom of their feet that they couldn't possibly run barefoot or in thin soled shoes.

TODAY DOCTORS STILL PRESCRIBE ORTHOTICS: Most sports medicine doctors treat many running injuries with running shoes with orthotics and thick heels. Now we have running shoes with very thin soles and minimal heels (such as Vibram Five Fingers or Dunlop Volley). Indeed, Vibram supported Dr. Lieberman's studies.

Who Gets High Blood Pressure from Salt?

2013-03-14T18:53:00.001-04:00

Not everyone gets high blood pressure from taking in too much salt. The people who are most likely to get high blood pressure from taking in too much salt are those whose cells do not respond well to insulin (Hypertension, Jan 2013). People whose cells do not respond well to insulin are called "insulin resistant". On the other hand, those whose cells respond well to insulin are called "insulin sensitive". They can develop high blood pressure from not taking in enough salt.

SALT RESTRICTION ISN'T FOR EVERYONE. Thirty-five years ago, researchers first described people whose blood pressure and weight rise when they take in extra salt. They are called "salt sensitive". They gain weight because their kidneys cannot get rid of the extra salt. The extra weight is caused by retaining extra fluid. Eventually, taking too much salt can cause salt-sensitive people to suffer kidney damage as evidenced by leaking protein (albumin) into their urine. (Diabetes Res Clin Pract, April 1998;39 Suppl:S15-26). Those who do not develop high blood pressure when they take in large amounts of salt are called "salt insensitive".

DEFINITION OF INSULIN RESISTANCE: Most cases of high blood sugar in diabetics are caused by inability of cells to respond to insulin, not by lack of insulin. Before insulin can do its job of driving sugar from the bloodstream into cells, it must first attach to special hooks on the outer cell surface called insulin receptors. Anything that blocks insulin from attaching to its receptors on the surface of cells can cause high blood sugar levels and high blood pressure. People who respond normally to insulin usually do not get high blood pressure from taking in too much salt. Insulin receptors are blocked by eating red meat, eating animal saturated fat, lack of exercise, excess fat in fat cells, overweight, fat stored in the belly, not eating enough fruits and vegetables, and lack of vitamin D.

THIS STUDY: People who are salt sensitive and have high blood pressure are usually fatter, and have higher blood levels of creatinine, cholesterol, aldosterone, glucose and insulin (Hypertension, Jan 2013).
• Creatinine goes up when the kindeys are damaged.
• Aldosterone is secreted by the adrenal glands to cause the body to retain salt.
• Blood sugar goes up when insulin receptors are blocked.
• Insulin goes up when blood sugar levels rise.

SALT-SENSITIVE PEOPLE HAVE A HIGH RISE IN INSULIN WHEN THEY TAKE IN EXTRA SALT. Fasting blood sugar levels are usually normal and did not differ between salt sensitive and salt resistant people with high blood pressure regardless of how much salt they took in. However fasting blood levels of insulin increased in salt sensitive patients when they took in extra salt (Am J Hypertens, 1998 (Apr);11(4 Pt 1):397-402). . The extra salt causes high insulin levels which constrict arteries to raise blood pressure. People who have insulin resistance at low salt intake will have much more insulin resistance at a higher intake of salt. For them, a high salt intake increases blood pressure, insulin, and blood sugar.

HOW TO TELL IF YOU ARE INSULIN INSENSITIVE AND THEREFORE PROBABLY SHOULD RESTRICT SALT: People who are insulin insensitive usually have what is called metabolic syndrome. You have metabolic syndrome if you have any three of the following:
• storing fat primarily in your belly
• having small hips
• being overweight
• having blood triglycerides (>150)
• having blood HDL cholesterol (<40 br=""> • having a fatty liver
• having a fasting blood sugar >100 (HbA1c> 5.7)
• having high insulin levels
• having high blood pressure

EVERYONE SHOULD CHECK HIS OR HER BLOOD PRESSURE: Get a blood pressure cuff. Take your blood pressure just before you go to bed. If your systolic blood pressure is above 120 much of the time, you have high blood pressure and should check with your doctor to see if you are salt sensitive and therefore, should restrict salt (and make other lifestyle changes).

Being Overweight Does Not Prolong Lives

2013-01-14T16:55:00.002-05:00

A recent meta-analysis of a hundred large studies showed that being a little bit overweight offers slight protection (a six percent decrease) from premature death (Journal of the American Medical Association, January 2, 2013). This study has been widely reported in the media, with headlines such as "Our Imaginary Weight Problem".

Instead of being told that overweight is beneficial, people should continue to hear that excess weight shortens lives, particularly if their fat is stored in the belly.

WHY THE REPORT IS FLAWED: People with wasting diseases usually lose weight long before they die. All chronic diseases that shorten lives have a tendency to make people lose weight. Heart diseases, cancers, late stages of diabetes, kidney failure, arthritis, and even aging itself, usually cause weight loss before death (J Cachexia Sarcopenia Muscle, 2012;3(1):1-4). Weight loss that precedes death can last as long as 10 to 20 years, so it is impossible to correct epidemiological studies for this effect.

As people with wasting diseases approach death, their rate of weight loss increases dramatically. Sicker people, and those closer to death, lose weight faster than people with wasting diseases whose immunities are successfully holding their diseases at bay. It is true that people who have diseases that will eventually kill them may live longer as long as they do not lose weight.

EVEN A LITTLE BIT OF FAT IN YOUR BELLY CAN KILL YOU. Not all fat is harmful. Fat stored on your hips and upper legs protects you from disease. It does not turn on your immunity or cause inflammation; and it helps to prevent diabetes and heart attacks.

However, fat located inside your belly and around your organs:
• turns on your immunity to cause inflammation that leads to cancers, heart attacks, strokes, diabetes, inflammatory types of arthritis and so forth; and
• blocks insulin receptors to raise blood sugar levels, leading to diabetes that can damage every cell in your body.

This large study should not make you believe that being overweight is beneficial. You should maintain a healthful weight and try to lose any excess fat that you have in your belly. Belly fat is harmful and shortens lives.

Coconut Water Is Not a Special Sports Drink

2012-08-30T13:12:00.000-04:00

The headline reads: "Coconut Water Is an Excellent Sports Drink" (Science Daily, August 20, 2012; presented at the 244th National Meeting & Exposition of the American Chemical Society (ACS) in Philadelphia). The author states: "Coconut water is a natural drink that has everything your average sports drink has and more. It has five times more potassium than Gatorade or Powerade. Whenever you get cramps in your muscles, potassium will help you to get rid of the cramps. It's a healthy drink that replenishes the nutrients that your body has lost during a moderate workout."

This flies in the face of everything I have learned about potassium:

• POTASSIUM DEFICIENCY IS NOT A PROBLEM IN HEALTHY EXERCISERS. In 1967, Dave Costill of Ball State University tried to create potassium deficiency in runners. He couldn't do it because potassium is found in all foods except refined sugar, and his athletes would not stay on a diet that consisted only of hard candy. The kidneys and sweat glands conserve potassium so well that you don't lose much. If an athlete develops potassium deficiency, it is usually caused by drugs, such as diuretics or corticosteroids, or by diarrhea or repeated vomiting. Some athletes try to control their weight by making themselves vomit. This is called bulemia, and the person usually denies vomiting. Their physicians can prove that they are vomiting by ordering blood and urine tests. If blood levels of potassium are low and urine levels are high, vomiting is the likely cause.

• POTASSIUM DEFICIENCY IS NOT A USUAL CAUSE OF CRAMPS OR TIREDNESS IN EXERCISERS. Tiredness and cramps in athletes can have many causes, but lack of potassium in the diet is not one of them. Athletes who are tired and suffer frequent muscle cramps need an evaluation for other causes of chronic tiredness. If none can be found, the athlete may be overtraining and should talk to the coach or a personal trainer about changing workouts.

• THE ONLY MINERAL THAT EXERCISERS NEED TO REPLACE IS SODIUM, COMMON TABLE SALT. The definitive studies on minerals and exercise were done during World War II. Dr. James Gamble of Harvard Medical School paid medical students to lie on rafts in his swimming pool, taking various amounts of fluids and salt and having blood drawn to measure salt and mineral levels. He showed that you have to take a lot of salt when you exercise for several hours, particularly in hot weather. For many years after that, students at Harvard Medical School heard Dr. Gamble give his lectures on minerals and exercise, and today, most serious students still read the Gamble lectures published in 1958 by The Harvard University Press. Now, more than sixty years later, nobody has improved on his research.

After Gamble published his studies, people who worked or exercised in hot weather were given salt tablets. Then doctors became concerned because they thought that a person could have his blood pressure raised by taking in too much salt, so they recommended restricting salt, causing many people to suffer heat stroke and dehydration during hot weather exercise. A low-salt diet does not lower high blood pressure for most people. A high-salt diet causes high blood pressure usually only in people with high blood insulin levels. Eating salty foods and drinks when you exercise for more than two hours is unlikely to raise blood pressure. We don't recommend salt tablets because they can cause nausea and vomiting, but you can use table salt or any salty food.

If you don't take salt and fluids during extended exercise in hot weather, you will tire earlier and increase your risk for heat stroke, dehydration and cramps. We eat heavily- salted potato chips or peanuts and drink fluids at least every 15 minutes when we ride in hot weather. Potassium deficiency doesn't occur in healthy athletes. The only mineral that athletes need to take when they exercise is salt.

If you like the taste of coconut water, it is a perfectly satisfactory fluid to take during exercise, but don't believe claims that it has any special benefits as a sports drink. If you use it during intense exercise, you will need other sources of sugar and salt.

Calcium Pills May Increase Heart Attack Risk

2012-06-15T19:56:00.001-04:00

A German study followed 24,000 men and women, ages 35 to 64, for 11 years and found that those who took calcium supplements were 86 percent more likely to suffer heart attacks than those who do not (Heart, published online May 23, 2012). More than 60 percent of North American women over 60 take calcium supplements to help prevent bone fractures (U.S. Centers for Disease Control and Prevention's National Center for Health Statistics, 2011).

In the study from Germany, there was no significant difference in death from stroke or heart attack no matter how much calcium people got FROM FOODS. There was even a suggestion that increased calcium intake from foods was associated with increased heart attack risk. Other factors that increase heart attack risk were excluded from the study.

Another study showed that calcium pills may reduce fractures by 10 percent, but can INCREASE risk for heart attacks by 25 percent (British Medial Journal, published online July 2010). Thus if 1,000 people were given calcium for five years, there would be 26 fractures prevented but there would also be 14 heart attacks, 10 strokes and 13 deaths more than in people not taking calcium pills.

OTHER STUDIES SHOW THAT TOO MUCH CALCIUM FROM FOOD AND PILLS INCREASES HEART ATTACK RISK: Eight studies followed more than 10,000 patients, average age of 68 years, for an average 3.8 years, taking 500 to 1400 mg calcium daily. They had 1.3 times the chance of suffering a heart attack as people taking no calcium pills. Those taking more than 805 mg calcium per day from food without pills were 1.86 times more likely to suffer heart attacks (British Medical Journal, 2010;341:3691).

HOW TOO MUCH CALCIUM CAN CAUSE HEART ATTACKS: Calcium supplements raise blood calcium levels which increases chances of forming clots, a major cause of heart attacks and strokes (J Bone Miner Res. 1997;12:1959-70). Calcium supplements can thicken neck artery plaques (Atherosclerosis, 2007;194:426-32) and calcify main arteries (J Bone Miner Res, 2010;25:505-12). Taking calcium without also taking vitamin D increases heart attack risk even further, because calcium blocks the activation of vitamin D to cause a relative deficiency of that vitamin.

TOO MUCH VITAMIN D RAISES CALCIUM: Vitamin D markedly increases calcium absorption to raise blood calcium levels. Researchers at the University of Copenhagen followed almost 250,000 people and found that people with blood levels of hydroxy vitamin D below 10 nmol/L were 2.3 times more likely to die prematurely and those with levels above 140 nmol/L were 1.42 times more likely to die prematurely (Journal of Clinical Endocrinology and Metabolism, published online May 2012). So both low and high calcium levels are harmful.

GET YOUR CALCIUM FROM FOOD, NOT PILLS: Adult men and women need 1,000 to 1,200 milligrams of calcium daily, according to the National Institutes of Health. You get that amount from a cup of yogurt, a glass of milk and a slice of cheese. If you avoid dairy products, you could meet your calcium requirement with a bowl of enriched cereal, a glass of fortified orange juice, half a cup of tofu and a piece of salmon.

GET YOUR VITAMIN D FROM SUN OR PILLS: You cannot meet your needs for vitamin D from foods. You have to depend on the sun or pills. Get a blood test for hydroxy vitamin D. If it is above 75 nmol/L, you are fine. If it is above 140 nmol/L, you are taking overdoses of vitamin D and should reduce your intake of vitamin D pills.

If your blood level of hydroxy vitamin D is below 50 nmol/L, you need more sunlight or you can try taking up to 2000 IU of vitamin D per day for a month. Once blood levels of vitamin D are above 50 nmol/l, you should reduce your intake of the pills to 1000 IU per day or less.

How to Recover from Muscle Soreness Caused by Intense Exercise

2012-05-27T21:28:00.000-04:00

Muscle soreness should be part of every exercise program. If you don't exercise intensely enough on one day to have sore muscles on the next, you will not gain maximum fitness and you are also losing out on many of the health benefits of exercise. The benefits of exercise are much greater with intense exercise than with casual exercising.

You must damage your muscles to make them grow and become stronger. When muscles heal, they are stronger than they were before you damaged them. All athletes train by "stressing and recovering". On one day, they take a hard workout in which they feel their muscles burning. Eight to 24 hours after they finish this intense exercise, their muscles start to feel sore. This is called Delayed Onset Muscle Soreness (DOMS). Then they take easy workouts until the soreness is gone, which means that their muscles have healed.

DOMS IS CAUSED BY MUSCLE DAMAGE. Muscles are made up of fibers. The fibers are made up of a series of protein blocks called sarcomeres that are lined in a long chain. When you stretch a muscle, you stretch apart the sarcomeres in the chain. When sarcomeres are stretched too far, they tear. Your body treats these tears in the same way that it treats all injuries, by a process called inflammation. Eight to 24 hours after an intense workout, you suffer swelling, stiffness and pain. The most beneficial intense exercise program is:

• severe enough to cause muscle pain on the next day, and
• usually allows you to recover almost completely within 48 hours.

ACTIVE, NOT PASSIVE, RECOVERY: When athletes feel soreness in their muscles, they rarely take days off. Neither should you. Keeping sore muscles moving makes them more fibrous and tougher when they heal, so you can withstand greater forces and more intense workouts on your hard days. Plan to go at low intensity for as many days as it takes for the soreness to go away. Most athletes try to work out just hard enough so that they recover and are ready for their next hard workout in 48 hours.

TIMING MEALS TO RECOVER FASTER: You do not need to load extra food to recover faster. Taking in too much food fills your muscle cells with fat, and extra fat in cells blocks the cell's ability to take in and use sugar. Sugar is the main source of energy for your muscles during intense exercise. Using sugar to drive your muscles helps them to move faster and with more strength.

Timing of meals is more important than how much food you eat. Eating protein- and carbohydrate-containing foods helps you recover faster, and the best time to start eating is as soon as you finish a hard workout.

At rest, muscles are inactive. Almost no sugar enters the resting muscle cell from the bloodstream (J. Clin. Invest. 1971; 50: 2715-2725). Almost all cells in your body usually require insulin to drive sugar into their cells. However during exercise your muscles (and your brain) can take sugar into their cells without needing insulin. Exercising muscles are also incredibly sensitive to insulin and take up sugar into their cells at a rapid rate. This effect lasts maximally for up to an hour after you finish exercising and disappears almost completely in around 17 hours. The best time to eat for recovery is when your cells are maximally responsive to insulin, and that is within a short time after you finish exercising.

Not only does insulin drive sugar into muscle cells, it also drives in protein building blocks, called amino acids. The sugar replaces the fuel for muscle cells. The protein hastens repair of damaged muscle. Waiting to eat for more than an hour after finishing an intense workout delays recovery.

WHAT TO EAT AFTER YOUR INTENSE WORKOUTS: Fatigue is caused by low levels of sugar, protein, water and salt. You can replace all of these with ordinary foods and drinks. If you are a vegetarian, you can replace your protein with combinations of grains and beans. You can replace carbohydrates by eating virtually any fruits, vegetables, whole grains, beans, seeds and nuts.

A recovery meal for a vegetarian could include corn, beans, water, bread, and fruits, nuts and vegetables. If you prefer animal tissue, you can get your protein from fish, poultry or meat. Special sports drinks and sports supplements are made from ordinary foods and therefore offer no advantage whatever over regular foods.

BODY MASSAGE: Many older studies have shown that massage does not help you recover faster from DOMS. Recently, researchers at McMaster University in Hamilton, Ontario showed that deep massage after an intense workout causes muscles to enlarge and grow new mitochondria (Science Translational Medicine, published online Feb, 2012). This is amazing. Enlarging and adding mitochondria can help you run faster, lift heavier weights, and even prevent heart attacks and certain cancers. See http://www.drmirkin.com/public/ezine021212.html (second article).

NSAIDS DELAY DOMS RECOVERY: Non-steroidal anti-inflammatory drugs (NSAIDS), such as ibuprofen, may help relieve pain, but they also can block muscle repair and delay healing. See http://www.drmirkin.com/public/ezine090609.html

HOT BATHS: Most research shows that a hot bath is not much better than doing nothing in helping muscles recover from exercise (European Journal of Applied Physiology, March 2006),

COLD OR ICE BATHS: A recent review of 17 small trials, involving 366 participants, showed a minor decrease in DOMS with ice water baths. They found "little quality research" on the subject and "no consistent method of cold water immersion" (Cochrane Library, published online February 15, 2012). Cold water immersion can reduce swelling associated with injury, but has not been proven to speed the healing of DOMS.

Lack of Exercise, Not Aging, Causes Weakness and Loss of Muscle in Older People

2012-03-22T21:34:00.001-04:00

Aging does not cause you to lose muscles. Loss of muscle is caused by lack of exercise. You can preserve both muscle size and strength by continuing to exercise ahttp://www.blogger.com/img/blank.gifs long as you live. Compare the MRIs of the legs of 40- and 70-year-old triathletes, and a 70-year-old non-exerciser:

The dark areas are muscle, the light areas are fat. Which legs would you rather have?

Forty competitive athletes, aged 40-81, who trained four to five times a week, had the same size muscles, the same absence of fat around their muscles, and close to the same strength as much younger athletes (The Physician and Sportsmedicine, September 2011). Many of the diseases and debilitating conditions associated with aging are caused by lack of exercise. "Exercise decreases body fat and obesity, increases muscle strength, improves balance, gait, and mobility, decreases likelihood of falling, improves psychological health, reduces arthritis pain, and heart attacks, osteoporosis, cancer, and diabetes."

After age 40, the average person loses more than eight percent of muscle size per decade. This loss increases to 15 percent per decade after age 75 years. Older people who lose muscles are four times more likely be disabled, have difficulty walking, and need walkers and other mechanical devices to help them walk (Am J Epidemiol, 1998; 147(8):755-763).

Exercise Makes You Smarter

2012-02-27T19:18:00.001-05:00

People who exercise regularly are far less likely to suffer dementia and had less than half the risk of death during the 17-year study period, compared to those who do not exercise (Medicine & Science in Sports & Exercise, February, 2012).

Researchers followed 45,000 men and 15,000 women, ages 20 to 88 years, in the United States for an average of 17 years. Six times as many people in the low fitness group suffered from dementia, compared to those who exercised regularly. While deaths in the United States associated with heart disease, breast cancer and stroke have declined in recent years, deaths related to dementia and Alzheimer's disease rose 46 percent between 2002 and 2006.

Another exciting study, from Japan, shows that many of the benefits that exercise provides to muscles are also provided to your brain (The Journal of Physiology, February, 2012;590(Pt 3):607-16).

THE STUDY: Adult male rats exercised to exhaustion at moderate intensity on a treadmill. Glycogen, sugar stored in muscles, was depleted by 82-90 percent. One day later, the rats' muscles could store 43-46 percent more than they could originally, In a like manner, brain glycogen levels decreased by 50-64 percent with exhaustive exercise, and were able to store 29-63 percent more on the next day. The greater the depletion of sugar in muscles and brain, the greater the ability to store more sugar after the rats were fed. The brain filled with sugar before the muscles did and after four weeks of training, the rats' brains could store significantly more glycogen.

EXPLANATION: Sugar is the most efficient source of energy for your muscles during intense exercise. Sugar is the most efficient source of energy for your brain ALL the time. When you exercise regularly, you increase the ability of your muscles to store sugar so you can move faster and longer. This study suggests that exercise also increases the energy supply to your brain, which will help you to think and reason better.

Rheumatoid Arthritis Patients Benefit from Cortisone Injections

2012-02-11T20:49:00.001-05:00

Cortisone-type injections into joints control painful rheumatoid arthritis by blocking protein changes that damage joints (Arthritis Research & Therapy, published online Feb. 2012).

REACTIONS THAT CAUSE RHEUMATOID ARTHRITIS: Rheumatoid arthritis (RA) is characterized by the production of PAD enzymes that convert an amino acid, arginine, into citrullinated proteins. Then the victim's immunity makes highly specific anti- citrullinated protein antibodies that attack the synovium and cause it to swell, thicken, and hurt.

WHY CORTISONE INJECTIONS WORK: Injecting cortisone-type drugs into the joints blocks the production of the PAD enzymes that produce citrullinated proteins, and this decreases the thickness of the synovium, and the resultant pain.

THE STUDY: The authors biopsied the swollen knees of patients with rheumatoid arthritis and normal controls. One group was given methotrexate, a common RA treatment used for more than 40 years. The other group was given cortisone-type injections (40 mg triamcinolone hexacetonide) into the knee joint.

Antibodies to citrullinated proteins were found in 86 percent of biopsy samples from the RA patients and in none of the healthy tissue samples. After eight weeks, those receiving the cortisone- type injections had far less swelling of their synovia, far less evidence of inflammation under the microscope, and lower levels of cutrullinated proteins and PAD enzymes. Methotrexate had no effect on citrullinated proteins, PAD enzymes or inflammation in the synovium, although these patients did feel better.

CONCLUSION: This study explains why cortisone-type injections are such an effective treatment for rheumatoid arthritis. However, the effects of the injections do not last and a few months later, the patient may need another injection that may increase risk for diabetes, osteoporosis, and other side effects.

Fasting Slows You Down

2012-01-31T20:43:00.000-05:00

Fasting for just a few hours slows an athlete down and the longer he fasts, the slower he moves. A recent study from Denmark shows that after 72 hours of fasting, a person's muscles accumulate far more fat and glycogen (stored sugar) than after 10 hours of fasting (American Journal of Physiology, Endocrinology and Metabolism, January 2012). This slows a competitive athlete down because it keeps muscles from responding to insulin and using more sugar for energy.

Insulin drives sugar into muscles most effectively when muscles are low on sugar and fat. Filling muscles with sugar or fat blocks insulin and reduces the amount of sugar that can enter muscle cells. Remember that when you exercise for more than an hour, you need to keep on taking sugar. The more intensely you exercise, the greater percentage of sugar your muscles use for energy. Emptying your muscles of sugar causes sugar to enter muscles even faster.

LACK OF SUGAR LIMITS SPEED: The time it takes to get oxygen into muscles is the limiting factor for how fast an athlete can move in competition. If he can get more oxygen into muscles, he will move faster. Muscles use fat, sugar and (to a lesser degree) protein for energy. Since sugar requires the least oxygen, an athlete moves faster when his muscles burn a greater percentage of sugar. If he fasts, he gets almost all of the energy to drive his muscles from his own body fat. Using fat for energy requires more oxygen, so he has to slow down.

MUSCLES CAN STILL FILL WITH SUGAR DURING FASTING: How can muscles start to fill up with sugar after three days of fasting? With fasting, the body breaks down its own protein for energy. Protein is made up of chains of building blocks called amino acids. Some of the amino acids are called branched-chain amino acids. The liver can convert these amino acids into sugars (called gluconeogenesis) which then travel in the bloodstream to be stored in muscles as glycogen.

HOW TO EAT TO COMPETE: If you are competing in sporting events that require speed, you should eat a meal that contains carbohydrates closer than three hours before the start of your event. If the event lasts more than an hour, take some source of sugar during your event, such as sugared drinks, fruit, candy, grain bars or dried fruit paste (fruit leather).

Cancer Cells Need More Sugar

2012-01-16T18:13:00.003-05:00

Cancer cells are different from normal cells. Every normal cell in your body has programmed into its genetic material, a process called APOPTOSIS, that lets it live and multiply only so long and then it dies. For example, skin cells live 28 days and die; cells lining your mouth live 24-48 hours and die; and red blood cells live up to 120 days. Cancer cells lose their ability to die. They try to live forever and they kill by going from one type of tissue to invade another type of tissue and destroy it. For example, breast cancer cells can eventually spread to your brain or lungs. They replace and destroy these tissues, and you die because your brain or lungs are not able to work properly.

Cancer cells grow and multiply so rapidly that they need huge amounts of the sugar, glucose, to supply them with the energy necessary for growth. Let me explain why cancer cells need so much sugar.

HOW CELLS GET ENERGY: All cells get their energy from two major processes:
• glycolysis, and
• the Krebs Cycle.
Normal cells primarily use the Krebs Cycle for energy since it is more efficient and provides more energy. However, cancer cells do not use the Krebs Cycle well, and therefore must depend on glycolysis. Because they use this inefficient pathway for energy, cancer cells that have forgotten to die have an incredible increase in need for energy from the sugar, glucose. Since insulin drives sugar into cells, insulin and ILGF-1 (insulin-like growth factor-1) feed cancer cells glucose, encouraging them to grow and multiply.

CANCER CELLS USE GLYCOLYSIS: In the early 1920s, Otto Warburg demonstrated that cancer cells can live without oxygen by getting their energy from glycolysis. Since glycolysis uses the single sugar, glucose, for energy, cancer cells use tremendous amounts of glucose to grow. Since cancer cells depend on glucose for energy, anything that interferes with the body's normal use of glucose supplies more sugar to the growing cancer cells, which will increase growth of an existing cancer and risk for new cancers. This is one of the reasons why diabetes and excess weight increase risk for cancer (see the third report below).

MITOCHONDRIA: In every cell are from a few to hundreds of small areas called mitochondria. They provide energy for cells through the Krebs Cycle, which is far more efficient than glycolysis, the process that supplies energy inside cells but outside the mitochondria. All cells need functioning mitochondria, where the Krebs Cycle occurs, to have apoptosis. Cancer cells have defective mitochondria which forces them to use glycolysis for energy. Since cancer cells have defective mitochondria, and do not use the Krebs cycle effectively, they do not have apoptosis, so they live indefinitely and kill by invading and destroying normal cells.

A CURE FOR CANCER? Researchers today are trying to cure cancer by blocking glycolysis. This could force mitochondria to become active again and use the Krebs Cycle for energy so that the cells can stop being cancerous and regain apoptosis, their programmable cell death. The chemical dichloroacetic acid (DCA), which increases the chemical reactions of the Krebs cycle in mitochondria, has been shown to kill cancer cells in laboratory tests and in animals. Anything that activates or restores mitochondria can restart apoptosis and cause cancer cells to kill themselves. At the University of Alberta, Dr. Evangelos Michelakis is doing research on DCA. Another activator of mitochondria, 3-BrOP, is being studied at The University of Texas M. D. Anderson Cancer Center. 2-deoxyglucose (2-DG) is being used at Emory University School of Medicine, and lactate dehydrogenase A is being researched at Johns Hopkins University.

DIANA'S FATHER WORKED WITH KREBS: In the 1930's, my wife Diana's father, Donald Purdie, was a professor at Cambridge University in England and spent his career working with Nobel Prize winner, Hans Krebs (1900-1981) whose research group worked out most of the chemical reactions that supply energy for cells. Her father published with Hans Krebs.

In the early 1940s, the Germans bombed England daily. Donald Purdie accepted the professorship and chair of the Department of Chemistry at Raffles College in Singapore, to get away from the war in Europe. Diana was born in Singapore in January 1942. Two weeks later, the Japanese invaded Singapore and her father was taken prisoner. The Japanese killed this great academic, starving him to death while he was forced to do manual labor to build the Burma-Thai railroad.

Diana and her mother and brother escaped on a boat that arrived in Bombay six weeks later. They then came to the United States and her mother didn't learn of Donald's death until three years later.

Environmental Factors Associated with Breast Cancer

2011-12-27T18:02:00.000-05:00

A recent report says that "Lifestyle Changes Prevent One-Third of Cancers", and that fewer than 10 percent of breast cancer cases are inherited (33rd Annual San Antonio Breast Cancer Symposium, 12/7/2011).

Anything that increases a woman's exposure to estrogen also increases her risk for breast cancer, a disease that affects one in eight women:

• being overweight: Full fat cells make estrogen, so overweight women have more estrogen
• not exercising: lack of exercise increases risk for obesity
• drinking alcohol
• taking birth control pills
• taking estrogen and progesterone pills at any age
• starting periods before age 11
• starting menopause after age 55
• never being pregnant (thus more menstrual cycles)
• never breast feeding

Radiation from too many medical tests also increases breast cancer risk. Three abdominal CT scans give as much radiation as atomic bomb survivors received. Possible, but unproven, causes of breast cancer include: smoking, second-hand smoke, nighttime shift work, exposure to benzene and other chemicals, or to BPA and certain other plastics ingredients.

There is no evidence that breast cancer is caused by hair dyes or by radiation from cellphones, microwaves or other electronic gadgets.

WHY DOCTORS PRESCRIBE PROGESTERONE: Taking progesterone and estrogen markedly increases breast cancer risk. Estrogen stimulates the inner lining of the uterus to grow, and uncontrolled growth is cancer. Taking estrogen can cause uterine cancer, while progesterone stops estrogen from stimulating the uterus. So, to prevent uterine cancer, doctors usually prescribe progesterone with estrogen to any woman who still has a uterus. However, taking both estrogen and progesterone increases breast cancer risk. Many doctors now recommend no hormone therapy for women at menopause.

Why Three out of Four Athletes Take Caffeine Before Competition

2011-12-09T18:52:00.000-05:00

In January 2004, the World Anti-Doping Agency removed caffeine from its prohibited drug list to allow athletes to take coffee, tea, chocolate, cocoa, guarana, cola drinks, energy drinks and so forth. Researchers have now measured the caffeine concentration in 20,686 urine samples obtained for doping control from 2004 to 2008. They found that 75 percent of athletes in official national and international competitions had consumed caffeine before or during competition (Appl Physiol Nutr Metab, Aug 2011;36(4):555-61). As expected, athletes in endurance sports (triathlon, cycling, and rowing) had the highest urine concentrations of caffeine. Gymnasts had the lowest urine caffeine concentration. Athletes older than 30 had higher levels of caffeine in their urine than those younger than 20. Males and females had the same urine concentrations.

HOW CAFFEINE INCREASES ENDURANCE: The limiting factor to how fast you can move during a race is the amount of oxygen that you can take in and use. Since sugar requires less oxygen than fat to power your muscles, you want to get sugar into your muscles as quickly as possible. Anything that increases the amount of sugar that can be absorbed from your intestines into your bloodstream will help you ride or run faster and longer.

When you exercise, caffeine can increase endurance by increasing the absorption of sugar from your intestines (Medicine & Science in Sports & Exercise, July, 2010) and by increasing the uptake of sugar by your exercising muscles by as much as 26 percent (Journal of Applied Physiology, June 2006).

Caffeine helps athletes run faster in both short and long-distance races. In short races, it makes athletes faster by causing the brain to send messages along nerves to cause a greater percentage of muscle fibers to contract at the same time. In longer races, it delays fatigue by preserving stored muscle sugar. Muscles get their energy from sugar and fat in the bloodstream, and from sugar, fat and protein stored in the muscles. When muscles run out of their stored sugar, they hurt and become more difficult to coordinate. Caffeine causes muscles to burn more fat, thus sparing stored muscle sugar to delay fatigue.

HOW MUCH DO YOU NEED? Most research shows that it doesn't take much more than one or two soft drinks to increase endurance. Caffeine loses its beneficial effects with repeated exposure, so athletes who want to gain maximum advantage from caffeine during competition should avoid drinking caffeinated beverages when they are not competing.

HOW MUCH IS SAFE? Nobody really knows how much caffeine you can take in without harming yourself. At rest, caffeine is a diuretic, but during exercise it does not increase urination. Caffeine is a potent stimulant that can cause irregular heartbeats and raise blood pressure.

RESTRICT CAFFEINE WHEN NOT COMPETING: Caffeine increases sugar absorption from the gut. Taking caffeine when you eat carbohydrate-containing foods can double your rise in blood sugar (Journal of Caffeine Research, April 16, 2011). Since more than 35 percent of North Americans will become diabetic and have high rises in blood sugar levels after meals, most people should not take caffeinated drinks with meals that contain carbohydrates: bread, spaghetti, or sugared foods and drinks. If you are already diabetic, your blood sugar levels rise even higher and you suffer cell damage. This cell damage causes all of the horrible side effects of diabetes: blindness, deafness, heart attacks, strokes and so forth.

Sarcopenia: Muscle Loss with Aging

2011-11-19T21:20:00.000-05:00

Competitive masters athletes, 40 to 81 years old, who trained four to five times per week did not lose any muscle size or significant strength with aging (The Physician and Sportsmedicine, October 2011;39(3):172-8). This shows that loss of muscle size and strength in older people is caused by lack of exercise, not just with aging. The athletes did gain fat in spite of exercising. Those in their 70s had almost as much strength and thigh muscle size as those in their 40s.

MOST PEOPLE LOSE MUSCLE: Recent studies show that after age 40, men lose more than eight percent of their muscle size each decade, and this loss of muscle increases after age 70. The people who lose the most muscle are usually the ones who die earliest. They are also most at risk for falls and broken bones.

HOW EXERCISE PREVENTS MUSCLE LOSS WITH AGING: Muscles are made up of thousands of individual muscle fibers. Each muscle fiber is innervated by a single nerve. With aging, humans lose the nerves that innervate muscle fibers, and with each nerve loss, they lose the associated muscle fiber so muscles become smaller. We used to think this happens because of aging. However, this new study and others show that lifelong competitive athletes do not lose the nerves that innervate their muscles with aging. They retain the nerves and therefore retain most of the muscle fibers that they would have lost if they were inactive.

MESSAGE: If you exercise regularly, continue to do so. If you don't, check with your doctor and then get instructions on how to start an exercise program.

The Only Mineral Needed by Exercisers

2011-11-12T19:20:00.000-05:00

People who are serious exercisers can be harmed by the broad recommendations for all Americans to restrict salt intake. It is true that excess salt intake can cause high blood pressure, but heavy exercise usually helps to protect people from salt causing high blood pressure. The minimum salt requirement is 1,500 mg (1 teaspoon) of sodium a day. The average North American is told not to exceed 2,300 mg per day, but he ingests too much salt, between 3,100 and 4,700 mg of sodium per day.

FITNESS DOES NOT REDUCE SALT LOSS: This month a study from Spain shows that being fit does not reduce the concentration of salt in sweat (European Journal of Applied Physiology, November 2011). A person who exercises in the heat can lose far more than 4000 mg of salt. So in spite of the fact that most serious exercisers get a lot of salt from the massive amounts of foods that they eat, they can still become salt deficient.

SYMPTOMS OF SALT DEFICIENCY: If you are a serious exerciser and you suddenly are not recovering from your workouts as fast as you usually do, a common cause is loss of salt. Symptoms of salt deficiency include muscle weakness, soreness and cramps, loss of strength and tiredness. Get a blood test for sodium on the day after a hard workout. If your blood sodium is below 132 mmol/L, you need more salt.

SALT IS NECESSARY FOR SERIOUS EXERCISERS: In 1942 the US government commissioned James Gamble of Harvard Medical School to set mineral requirements for soldiers fighting in the Pacific. He showed that sodium (table salt) is the only mineral that needed to be replaced. Potassium, magnesium, calcium and the trace minerals were not significant. To this day, nobody has improved on his data and recommendations.

HOW SALT DEFICIENCY HAMPERS PERFORMANCE: Not taking in salt when you exercise for more than two hours can prevent you from retaining the water that you drink. It can also block thirst, so you may not know that you are dehydrated. Thirst is a late sign of dehydration. You lose water during exercise primarily through sweating, and sweat contains a far lower concentration of salt than blood. So during exercise, you lose far more water than salt, causing the concentration of salt in the blood to rise. You will not feel thirsty until the concentration of salt in the blood rises high enough to trip off thirst osmoreceptors in your brain, and it takes a loss of two to four pints of fluid to do that.

SALT BEFORE COMPETITION: Taking salt just before competition improves performance (Medicine and Science in Sports and Exercise, January 2007; Clinical Journal of Sport Medicine, January 2007). Athletes who took extra salt had larger blood volume and greater endurance. Salt makes you thirsty earlier so you drink more, and salt in your body holds water so you have more water available to meet your needs.

ENDURANCE EVENTS LASTING LONGER THAN FOUR HOURS: You can keep yourself fresh during extended exercise by eating foods with salt and drinking frequently, before you feel hungry or thirsty. Once you are weakened by loss of fluid or salt, it becomes very difficult to regain your strength. Commercial sports drinks help increase endurance with their caffeine, sugar, salt, and to a lesser degree, protein content. It is unlikely that any other component improves performance (The Physician and Sportsmedicine, April 2010).

MOST EXERCISERS DO NOT SUFFER FROM SALT DEFICIENCY: The North American diet contains up to 10 times your minimal salt requirements. Salt is added to almost all prepared foods, so if you doubled or tripled your salt losses through sweating, you would still not be deficient because you are already taking in far more salt than you need.

EXERCISE CAN PREVENT RISE IN BLOOD PRESSURE FROM SALT: People who exercise are far less likely to suffer high blood pressure from eating food with excess salt intake (presented at the American Heart Association Scientific Sessions, March 2011). High blood pressure increases risk for heart attacks, strokes, and kidney damage. Many middle-aged people who start an exercise program lose their tendency to develop high blood pressure when they take in extra salt (Journal of Human Hypertension, May 2006).

If you are concerned about your blood pressure, you can buy an inexpensive wrist cuff and check your systolic blood pressure at bedtime. If it is below 120, you probably do not need to restrict salt.

Exercise Increases Mitochondria in Brain Cells

2011-10-09T21:59:00.000-04:00

Exercise increases the size and number of mitochondria in the brains of mice (American Journal of Physiology, September 2011). The mice ran on a treadmill for an hour a day, six days a week, for eight weeks.

This could explain how exercise improves memory, treats depression, and makes people feel better and helps them to think more clearly. Until now, the leading theory to explain how exercise improves memory and treats depression was that exercise causes the brain to release endorphins, morphine-like compounds that can improve mood (Journal of Applied Physiology May 1982). However, endorphins would not explain the improvement in memory and brain function associated with a regular exercise program.

Mitochondria are tiny chambers in cells that turn food into energy more efficiently than any other process in your body. Scientists have known for years that exercise enlarges and increases the number of mitochondria in muscle cells, to increase strength, speed and endurance; but this is the first research paper to offer a plausible explanation why exercise improves memory and relieves depression.

The increase in brain mitochondria could also explain how training for sports increases endurance by making the brain resistant to fatigue. It also could explain how exercise treats mental disorders, delays aging, and improves certain types of nerve damage.

Chocolate Increases Endurance

2011-08-12T20:21:00.000-04:00

A recent symposium at the American College of Sports Medicine 58th Annual Meeting June 2, 2011 and other recent studies show that chocolate improves endurance training in mice and humans. Taking small amounts of a chocolate extract, called epicatechin, twice a day for two weeks shortened recovery from intense exercise and increased endurance in mice (Journal of Physiology, July 25, 2011). Drinking chocolate milk after all- out exercising helped athletes recover faster and cycle faster afterwards (Journal of Strength Conditioning Research, May 2011).

These studies do not encourage you to take chocolate just before competitions. They show that chocolate helps you to recover faster from hard exercise, and that you may benefit from taking small amounts of chocolate daily during hard training. All athletic training is done by taking a harder workout on one day, feeling sore on the next and taking easier workouts for as many days as it takes for the soreness to go away. If you can recover faster, you can do more intense training and be a better athlete.

Your body requires oxygen to convert food to energy to power your muscles during exercise. The limiting factor to how fast you can run or cycle, and how much force your muscles can generate, is the time it takes to move oxygen from your lungs into your muscles. The aim of all athletic training is to increase your body's ability to convert food to energy with the least amount of oxygen. Anything that increases oxygen supply or decreases oxygen needs will make you faster and stronger.

Your muscles convert food to energy primarily in your mitochondria, small chambers numbering from a few to thousands inside your muscles. Anything that grows new mitochondria or enlarges existing ones will make you faster and stronger. The cocoa bean contains chemicals called epicatechins that stimulate your muscles to grow and produce mitochondria. It takes only small amounts, taken regularly, to do this.

However, pure chocolate is very bitter, so manufacturers add huge amounts of sugar and saturated fats that should not be taken when you are not exercising. Eating refined sugar when you are not exercising causes a high rise in blood sugar that can damage every cell in your body and saturated fats from animals block insulin receptors to prevent insulin from clearing sugar from your bloodstream to raise blood sugar levels even higher.

• You can eat small amounts of sweetened chocolate when you are exercising.
• You should not eat sweetened chocolate when you are not exercising.
• You can eat chocolate every day that you exercise, particularly on your intense exercise days.
• You should take only small amounts as more is not more effective in hastening recovery. A reasonable daily amount would be about five grams of dark chocolate (1/6th of an ounce) per day.

Everyone Should Train like an Athlete

2011-07-31T19:48:00.000-04:00

All exercisers should follow the principles of training used by competitive athletes. You will gain far more health benefits from intense exercise than from more casual exercise, and you will gain more strength and muscle growth. Athletes do not do the same workouts every day. If they did, they would not gain the increased strength, speed and endurance that are necessary for competition. They take an intense workout in which they feel a deep burning in their muscles, feel sore on the next day, and take lighter workouts until the muscle soreness goes away. Then they take their next intense workout.

THE FIRST PRINCIPLE OF TRAINING - BACKGROUND BEFORE PEAKING: Never try to exercise at an intense pace when you start a new program. For example, if you are starting a stationary bicycle program, ride at a very slow pace every day until your muscles start to feel sore or tight and then stop. In the first six weeks, limit your workouts to no longer than a half hour. Only after you can exercise at a casual pace for 30 minutes every day should you try to increase the intensity of your workouts. You may also want to check with your doctor before you start exercising intensely. Intense exercise can kill people who have blocked arteries leading to their hearts, and many people do not know that they have this condition until it is too late. Even regular exercisers can suffer from blocked arteries and not know it.

INTENSE WORKOUTS: Athletes divide their intense workouts into periods of *sustained effort, *short intervals, *long intervals, and *combinations of these variations. If you are not competing in athletic events, you only need to do short intervals.

SHORT INTERVALS: A short interval takes less than 30 seconds because an athlete does not accumulate significant amounts of lactic acid in less than that time. Muscle burning is caused by increased acidity in the muscle caused by lactic acid accumulation.

An athlete can do a very large number of repeat short intervals, often 100 or more in a single workout. A top runner will run a large series of short runs up to 220 yards. Cyclists often use a clock. In short intervals, athletes get out of the burn soon after they feel it.

LONG INTERVALS; Long intervals usually last two minutes or more, and build up so much lactic acid in the bloodstream that a top athlete can only do a few of them in a workout. A runner may run four to eight half-mile repeats. Cyclists may push their intervals between lamp posts or use some other measure of fixed distance of all-out riding. Long intervals are done with such intensity that the athlete is short of breath and feels intense muscle burning during each interval.

INTENSE CONTINUOUS WORKOUTS: Cyclists often use sustained workouts as the basis of their training regimens. They pick up the pace and as soon as they start to feel the burning in their muscles, they let up on the pressure, slow down, and the burning goes away. Almost immediately afterwards, they start to pick up the pace and again back off as soon as they feel the burning. Getting out of the burn as soon as it occurs allows a cyclist to take this type of intense workout for many hours.

INCREASED STRENGTH COMES FROM MUSCLE DAMAGE: The soreness that you feel usually 8 to 24 hours after an intense workout is called Delayed Onset Muscle Soreness (DOMS). DOMS is caused by muscle damage itself. Biopsies show bleeding into the muscles fibers, and disruption of the fibers and the Z- bands that hold the muscle filaments together as they slide by each other. If you don't suffer muscle damage, you do not gain significant muscle growth.

MUSCLE BURNING DURING INTENSE EXERCISE: Muscle burning during exercise means that you are applying enough force on your muscles to pull the fibers apart and damage them. However, the longer you stay in the burn, the longer it takes for the muscles to heal. Most athletes do some form of interval training that takes them out of the burn soon after their muscles start to burn.

The burning feeling in muscles that is transmitted back to your brain is actually caused by the increased acidity brought on by a buildup of lactic acid in muscles. Muscle damage is caused by the pressure on the muscles from hitting the ground with your foot during running, or pressing very hard on your pedals, and has nothing to do with excessive buildup of lactic acid. It is caused by excessive force on muscles during intense exercise. Lactic acid starts being cleared from muscles within seconds of stopping exercise. Furthermore, lactic acid is the most efficient muscle fuel, since it requires less oxygen than any other source of energy.

Athletes exercise intensely until they feel a deep burning in their muscles and then let up on the pressure. The burning usually goes away almost immediately. Then they pick up the pace to increase the pressure on their muscles to cause the burning to return. They stop the interval workout when their muscles start to stiffen and hurt.

ACTIVE RECOVERY, NOT PASSIVE: On the day after an intense workout, the athlete's muscles are supposed to feel sore. If he takes off completely, he may recover faster, but he will never reach his potential in competition. Active recovery, in which a person exercises at reduced intensity, makes the muscles more fibrous and resistant to damage during hard workouts. This allows the athlete to take more intense workouts on his hard days and makes him a better athlete. He can compete only as fast as he moves on his hard days.

A TRAINING PROGRAM FOR YOU: Set up your program so that you plan to exercise faster on three days a week, never on consecutive days. Plan to exercise at very low intensity on your four recovery days. For example Tuesdays, Thursdays, and Saturdays will be your faster days. The other four days are for recovery.

If you are a runner or cyclist, run a little faster on your hard days and much more slowly on your recovery days. If your muscles feel sore or tight on scheduled hard days, skip that hard workout and do a very easy workout or take the day off. Injuries come from taking a hard workout when your muscles are still sore or tight from a previous intense workout.

HARD DAYS: Start out very slowly and as your muscles feel more comfortable, gradually pick up the pace. When you start to feel the least burning, immediately slow down and remain in that slow pace until the burning is completely gone. Then gradually increase the intensity until you reach the burn again, and immediately slow down. Continue to alternate bursts of increased intensity with slow recoveries until your legs start to feel stiff or you stop recovering from the burn or tightness. Then quit for the day.

EASY DAYS: You are not supposed to feel discomfort or burning on recovery (easy) days. If a workout on a recovery day prevents you from taking your hard workout on the next day, you exercised too intensely or long on your recovery day. Go for as long as you feel good and quit for the day when you feel tightness or discomfort. If you feel stiff or hurt in one group of muscles on one side of your body, take the day off. Soreness in one part of your body is a sign that you are developing an injury.

PROGRAM PROGRESS: Try to increase the intensity of your hard days, and do not increase the intensity of your recovery days. If you avoid injuries, you will become stronger and healthier.

ADVANCED PROGRAMS FOR ATHLETES: Training programs should be based on two very fast interval days, one very fast, prolonged day, and four recovery days. For example, try short intervals on Tuesdays, long intervals on Thursdays and sustained hard workouts or races on Sundays. The other four days are supposed to be so easy that they do not interfere with your recoveries to limit your hard-intense days or worse, cause injuries. Remember, if you do not recover for your next intense workouts, your easy days are too long or too intense, and you should do less, more slowly on your recovery days.

Muscle Cramps in Athletes and Exercisers

2011-07-23T18:31:00.001-04:00

This month a study from the University of Cape Town, South Africa showed that the athlete who is most likely to suffer muscle cramps is the one who runs the fastest and the one who has had previous muscle cramps (British Journal of Sports Medicine, June 2011). Of 210 triathletes competing in an Ironman triathlon, 43 developed severe muscle cramps, while 166 did not. There were no significant differences between groups in any pre-race or post- race blood mineral levels or body weight changes (a measure of dehydration). This supports many other studies that show that the most likely cause of muscle cramps in conditioned athletes is muscle damage. The most likely causes of muscle cramps in out-of-shape exercisers are lack of salt or water (1).

Cramps in athletes occur most commonly during intense exercise. Cramps occur far less often during less-intense training, because the most common cause of muscle cramps in exercisers is muscle damage from all-out pressure on the muscles.

Muscle damage: Most muscle cramps in serious exercisers and athletes are caused by an exaggerated "stretch reflex" triggered by muscle damage. When you stretch a muscle, it pulls on its tendon. Stretch reflex nerves in that tendon send a message back to the spinal cord (not the brain), and then the "stretch reflex" in the spinal cord sends a message along nerves from the spine to cause the muscle to contract. During extreme pressure on the muscles, muscles are damaged causing sustained contractions. A study from South Africa showed that the most likely causes of cramps are muscle fatigue or tearing of the muscle itself (2). Electromyograph (EMG) studies measure increased electrical activity from damaged muscles. EMGs show markedly elevated electrical activity of the nerves controlling cramped muscles. Furthermore, a review of the scientific literature shows the most common cause of muscle cramps appears to be muscle damage (3).

Warning signs: Before athletic cramps come on full force, you will usually feel the muscle pulling and tightening. If you slow down, the pulling lessens, but if you continue to push the pace, the muscle goes into a sustained cramp and you have to stop exercising to work the cramp out. Further evidence that muscle damage is the cause of the cramp is that the muscle often hurts for hours or days afterwards.

When a cramp strikes: Muscle cramps during endurance events can be prevented by slowing down when you feel excessive soreness in one muscle group or straining in a muscle. You do this by switching pressure from the cramped leg to the uncramped one. A bicycle racer moves most of his pressure to the pedal of the uncramped leg. A runner shortens the stride of the cramped leg. Continuing to put pressure on the cramped muscle can rupture the muscle.

Prevention: You may be able to prevent cramps by exercising more frequently but less intensely and for shorter periods of time, but most racers do not want to do this.

Other causes in non-athletes: Known medical causes of muscle cramps are extremely rare. If you suffer from recurrent muscle cramps, you may need special tests for pinched nerves, Parkinson's disease, low thyroid, diabetes, narrowed arteries from arteriosclerosis, low blood mineral levels, metabolic diseases that cause muscle damage, or side effects of drugs used for high cholesterol, high blood pressure or diabetes, diuretics, oral contraceptives or alcohol (4).

Dehydration or lack of minerals is less common. Some cramps are caused by low mineral or fluid levels (5). However, for the vast majority of trained athletes who suffer exercise- associated muscle cramps, blood levels of sodium, potassium, calcium and magnesium are normal. Research in athletes after they ran in 52-mile races showed that the runners who suffered cramps had the same level of dehydration and blood minerals as those who did not get muscle cramps.

Athletes should take extra salt anyway. Athletes need more salt than people who do not exercise. They lose a lot of salt through sweat. The most common mineral cause of muscle cramps in untrained people who exercise is lack of salt, according to a report from the University of Oklahoma (6). The authors found that intravenous saline can reverse cramping in exercisers, and that more salt in the diet or in sports drinks can help to prevent heat- associated cramping.

If you are concerned about excess salt raising your blood pressure, get a wrist cuff monitor and check your blood pressure every night before you go to bed. If your blood pressure rises above 120, you may need to restrict salt. (Excess salt can raise systolic blood pressure. Excess body fat, not salt, raises diastolic pressure.

Treatments that usually do not work: Nobody has shown consistent benefit for trained athletes from any of the most common treatments: multivitamin pills; mineral pills with calcium, zinc, magnesium, salt and/or potassium; massage or chiropractic manipulation; drinking large amounts of water; dietary manipulations; or bio-mechanical stretching and strengthening.

Medications: Quinine has been reported to help relieve muscle cramps in non athletes, but it can burst red blood cells. Some studies show that gabapentin (an anticonvulsant), diltiazem ( a blood pressure medication), or B-complex vitamins may help to relieve muscle cramps in some people (7).

Sugar: There is some evidence that taking sugared drinks or foods during prolonged exercise helps to maintain endurance and muscle integrity which helps to prevent cramps. Take a source of sugar frequently during vigorous workouts or races, and back off if you feel a group of muscles pulling or tightening during exercise.

Lack of vitamin D: A leading cause of muscle damage, soreness and slow-healing injuries in athletes is lack of vitamin D. If you suffer frequent cramping and your muscles feel sore or you keep on being injured when you exercise, get a blood test called D3. If it is below 75 nmol/L, your problems may be caused by lack of vitamin D and be cured by getting some sunshine or taking at least 2000 IU each day of the very inexpensive vitamin D3.

Occasional cramps are not harmful. Most racers and serious exercisers accept that occasional cramps will occur, and rarely cause serious injuries.

References:
1. Sports Medicine, April-May 2007
2. Medicine & Science in Sports & Exercise, July 2005
3. Journal of the American Academy of Orthopaedic Surgeons, July 2007
4. Neurology 2010; 74: 691-96
5. The Japanese Journal of Clinical Pathology, November 2007
6. Sports Medicine, April-May 2007
7. Journal of Clinical Pharmacology, 1998;38:1151

Hot Weather Exercise - What to Eat?

2011-07-08T13:13:00.001-04:00

To be able to exercise intensely in hot weather, you have to maintain water, sugar and salt in your body for the entire time you exercise. How fast you can ride, run, or exercise is limited by the time it takes to bring oxygen into your muscles. If you can increase the oxygen supplied, or decrease the oxygen needed, you can move faster. Since sugar requires less oxygen to power your muscles than fat or protein, anything that allows your muscles to burn more sugar and less fat will help you to move faster.

Taking extra sugar during a competition or intense exercise lasting more than two hours is far more important than what you eat before your event. The limiting factor to how fast and intensely you can exercise in events requiring endurance depends on how quickly you can get sugar into muscles during exercise. You can markedly improve performance in endurance sports by starting to eat and drink soon after you start exercising.

Do not take in sugar until at least five minutes after you start your competition. When you eat sugar and your muscles are not contracting, you get a high rise in blood sugar that causes the pancreas to release large amounts of insulin. This can cause a drop in blood sugar levels that can tire you. On the other hand, exercising muscles draw sugar rapidly from the bloodstream without needing insulin. So taking sugar during exercise usually does not cause the high rise in blood sugar levels that causes your pancreas to release large amounts of insulin.

The energy for your brain comes almost exclusively from the sugar in your bloodstream. When blood sugar levels drop, so do brain levels, and you feel tired and have difficulty coordinating your muscles.

Another reason why you have to take sugar during intense exercise is that there is only enough sugar in your bloodstream to last three minutes at rest. To maintain blood sugar levels, your liver constantly releases sugar into your bloodstream, but your liver holds only enough sugar to last about twelve hours at rest and far less than that when you exercise. When muscles run out of their stored sugar supply, it hurts to exercise and the muscles become difficult to control.

Don't wait to feel hungry: Hunger during exercise is a very late sign of not getting enough calories. By the time you feel hungry, your body will be so depleted of sugar that you will have to eat large amounts of carbohydrate-rich food just to restore your sugar supplies.

What to eat and drink: All carbohydrates are single sugars, or sugars bound together in twos, up to thousands and millions. Before any carbohydrate can be absorbed into your bloodstream, it must first be broken down into single sugars. Human intestines do not permit combination sugars to pass into the bloodstream, so the most effective way to increase endurance is to take sugar- containing foods and drinks during prolonged exercise.

Caffeine increases sugar absorption from the gut. Taking caffeine when you eat carbohydrate-containing foods and drinks can double your rise in blood sugar (Journal of Caffeine Research, April 16, 2011). A high rise in blood sugar causes all the side effects of diabetes: blindness, deafness, heart attacks, strokes and so forth. However, during exercise, caffeine can increase endurance (Medicine & Science in Sports & Exercise, July, 2010) by increasing the absorption of sugar from your intestines and by increasing the uptake of sugar by your exercising muscles by as much as 26 percent (Journal of Applied Physiology, June 2006). Caffeine is found in coffee, tea, chocolate, cocoa and caffeinated soft drinks.

CAUTION! Take caffeinated sugared drinks only during prolonged, intense exercise. Taking sugared drinks, with or without caffeine, when you are not exercising causes higher rises in blood sugars that increase risk for diabetes and cell damage. Read my comprehensive report on what to eat and drink before and during hot-weather competition

HPV + Sunlight Cause Many Skin Cancers

2011-06-21T20:19:00.001-04:00

We have known for many years that the Human Papilloma Virus (HPV) causes almost all warts on the skin, most head and neck cancers, and almost all cervical cancers. Now we find that HPV also causes the common skin pre-cancers called actinic keratoses, which can develop into squamous cell skin cancers that can spread through other parts of the body (Trends in Microbiology, January 2011). More than 60 million Americans suffer from actinic keratoses, scaly areas on sun-exposed skin primarily on the face, ears, scalp, neck, and dorsal surface of the hands.

Most actinic keratosis cells are infected with HPV, the viruses that cause warts (1 - see list of references below). Dr. Eggert Stockfleth, of the Charité Hospital in Berlin, found specific types of HPV (21, 5, 8, 16 and 18) that convert normal skin to the pre-cancerous actinic keratoses, which may then progress to become squamous cell cancers (2).

Recent research shows that these skin pre-cancers are caused by a combination of cumulative exposure to sunlight and HPV, which can be acquired through sexual contact (3).

How skin cancer starts:
Chronic exposure to ultraviolet light damages DNA in skin cells. Your immunity tries to repair this damage, but the Human Papilloma wart viruses can prevent your immunity from repairing the DNA. Most of the time when your DNA is damaged, the cells die because they have a programmable cell death called apoptosis. However, the HPV virus prevents DNA from healing and also prevents the programmable cell death that would have removed the damaged cells (4). Then you develop scaly areas and bumps on your skin called actinic keratoses. With further exposure to sunlight, HPV can cause these damaged cells that do not die to develop into squamous cell skin cancers that can spread through your body.

The more different HPV viruses you have, the more likely you are to develop skin cancers:
More than 150 different types of HPV exist. Some types of HPV (Types 8, 24 and 76) are far more likely to cause skin cancer than others. The ones most likely to cause cervical cancers are types 16, 18, 52 and 59. They are also the ones that persist the longest, and are most likely to cause cancers and abnormal PAP smears.

A person acquires these viruses usually, but not always, from a sexual contact, and then a person's immunity usually clears the virus in six to eight months. However, the more viruses a person picks up from other people, the more likely he or she is to go on to suffer squamous cell skin cancers (5).

The more sexual partners you have, the more likely you are to acquire and keep the cancer-causing HPV virus (6). Men 18 to 70 years old who were free of both HIV and cancer had HPV cultures taken every six months from several places on the penis and scrotum. Among the 1159 men, the incidence of new genital HPV infection was 3.8 percent every six months. Those who had the most sexual partners had the most HPV infections that cause cancer.

Positive cultures for HPV persisted for an average of 7.5 months, and for HPV 16, the type more likely to cause cancer, for 12.2 months. The more partners a person has, the less likely he is to clear the virus. Older people clear HPV faster than younger ones, probably because they have fewer new partners.

Most hpv infections go away:
If you don't acquire any of the other 150 HPV types from additional contact, most HPV infections appear to clear themselves without treatment (7). DNA tests of HPV show that 70 percent of women clear HPV infections in their cervix and vaginas within one year, and only nine percent continue to be infected after two years (8). A summary of several studies shows that 90 percent of HPV tests become negative in about two years.

The current theory is that you become infected with HPV, usually through sexual contact, and it can disappear without treatment, as cultures fail to find it. We do not know if the virus really goes away, but we usually cannot find it. However, some people never clear the high-cancer-risk types of HPV and it is the persistent infections that can lead to skin pre-cancers and cancers (9).

Additional exposure to HPV:
Infected people who continue to have the most sexual contacts are the ones most likely to continue to be infected with HPV. Each additional sexual exposure increases your chances for acquiring additional HPV viruses and the specific viruses that cause cancer.

You can have several different HPV virus types at the same time. Acquiring immunity to one type of HPV does not protect you from becoming infected with another type of HPV in the future. It is likely that the more HPV viruses that infect you and the more sunlight that damages your skin, the more likely you are to develop skin cancer.

How do you get HPV?
The most common way to acquire HPV is through rubbing skin on skin, usually through sexual contact, but any type of rubbing skin on skin has been associated with an increased risk. Non-penetrating skin-on-skin contact has caused HPV transmission even in virgins (10). The virus has repeatedly been found underneath the fingernails, so shaking hands can, at least theoretically, transmit the virus (11). Furthermore, HPV can be transmitted non-sexually from a mother to her child (12). HPV was found in up to 50 percent of pubic and anal hairs removed from patients with genital warts (13).

Condoms:
Condoms do not offer complete protection against HPV since any skin-to-skin contact can result in transmission of the virus (14). The virus can also pass around condoms in body fluids, such as saliva, semen and vaginal secretions.

New sexual partners:
You are most likely to acquire HPV from a new sexual partner, rather than an old one, as healthy people usually clear the virus from their bodies in six to eight months. Each new partner can give you new HPV infections and the more HPV viruses you have at one time, the more likely HPV is to persist and the greater your risk for developing cancers.

Public places:
It is extremely unlikely that you will pick up HPV from a public shower, sauna, or wet seat. Samples were collected with a toothbrush from the floor and seat surfaces of bathing resorts, showers, swimming pools, saunas, bathrooms and dressing rooms. No HPV DNA-positive samples were found (15).

Risk factors for oral cancers:
You are five times more likely to suffer oral cancer from HPV if you have had more than five oral-sex partners in their lifetime. You increase risk for HPV with
• increasing numbers of sexual partners,
• engaging in casual sex,
• having an early age at first intercourse, and
• using condoms infrequently (16).

Cofactors increase risk for cancer from HPV:
Many things you do increase your risk for cancer and the more risk factors you have, the greater your risk. Avoiding these risk factors after you are diagnosed with a cancer can increase your chance for a cure.

Smoking and being infected with HPV both cause fatal squamous cell cancers of the head and neck. A study from the University of Michigan shows that smokers who have an HPV-linked cancer are six times more likely to have a recurrence than those who have never smoked, and two-thirds of patients with HPV-linked tumors were current or former tobacco users (17). Among those with HPV-linked tumors, six percent of those who never smoked had recurrences, compared to 19 percent of those who had smoked in the past and 35 percent of current smokers. Almost all cases of cervical cancers are caused by HPV, but only one woman of 250 infected with HPV develops cervical cancer. If you are infected with HPV and smoke, you increase your chances of developing cervical cancer 15 times (18).

Lifestyle factors that are associated with increased cancer risk (as well as heart attack risk) include: smoking, taking more than two alcoholic drinks per day, being overweight, not exercising, not eating enough fruits and vegetables, eating too much saturated fat from mammals, eating burnt food (PAHs and HCAs), lack of vitamin D, lack of sunlight, and anything that increases risk for diabetes. Other risk factors include promiscuous behavior that exposes you to hepatitis B and C viruses, HPV, human immunodeficiency virus (HIV), Helicobacter pylori (H. pylori), Human T-cell leukemia/lymphoma virus (HTLV-1), Epstein-Barr virus (EBV), or Human herpes virus 8 (HHV8); working in jobs that expose you to radiation, chemicals such as asbestos, benzene, benzidine, cadmium, nickel, or vinyl chloride, certain metals, pesticides or solvents; taking certain medications and hormones; repeated exposure of your skin to excess sunlight or getting too many X rays.

Treatment of genital warts:
Virtually all genital warts are caused by HPV. Doctors treat genital warts by burning, freezing, lasering, scraping, or removing them surgically. They use chemicals to sensitize skin to sunlight and then use light to burn the warts off. They even peel them off. However, warts often return after all destructive procedures, so I usually recommend
• Fluoro-uracil cream (an anti-cancer drug),
• Imiquimod cream (a chemical that increases your immunity), or
• Diclofenac sodium gel (a drug that blunts your immune reaction).

Treatment for actinic keratoses:
I think that the most effective treatment for actinic keratoses is to use a generic version of imiquimod cream (brand name Aldara). It enhances your immunity so it can more effectively kill HPV. It is applied twice a week for 16 weeks, left on the skin for about eight hours and then washed off.

Current treatment by most dermatologists is to destroy the lesions of actinic keratoses with liquid nitrogen or electrocautery. Surgery is rarely needed. However, once an actinic keratosis becomes a squamous cell carcinoma, surgeons usually remove the entire cancer. A pathologist usually checks the removed tissue to see that there is a 360-degree margin of non-cancerous skin around the removed cancer.

References:
1. New England Journal of Medicine, May 15, 2003
2. Disease Markers, April 2007
3. Expert Review of Dermatology, April 2010
4. Cancer Detection and Prevention, June 2001
5. BMJ. 2010;341:c2986
6. The Lancet, published online March 1, 2011
7. Am J of Ob and Gyn, 2000;183(3): 561-567
8. NEJM, 1998;338(7):423-428
9. Trends in Microbiology, 2011(Jan);19(1):33-39
10. Scand J Infect Dis 1996;28(3):243-6
11. Sexually Transmitted Infections 1999 Oct;75(5):317-9
12. J Med Virol 1998 Nov;56(3):210-6
13. J Clin Microbiol. 1999 Jul;37(7):2270-3
14. Am J Epidemiol 2003 Feb 1;157(3):218-26
15. Rev Med Virol 1999 Jan-Mar;9(1):15-21
16. NEJM May 9, 2007
17. Clinical Cancer Research, February, 2010
18. Cancer Epidemiology, Biomarkers & Prevention, November 2006

Diverticulosis? Seeds and Nuts OK

2011-06-04T12:16:00.001-04:00

People with diverticulosis are usually told to avoid seeds and nuts, yet no scientific data support this recommendation (Nutrition in Clinical Practice, March 2011). Diverticulosis means that the colon has multiple outpouchings. The theory is that small food particles such as seeds might get caught in the outpouchings, but no one has shown that this actually happens. Furthermore, avoiding insoluble fiber found in all parts of plants is likely to increase risk for diverticulosis.

When solid food reaches the stomach, the pyloric sphincter closes and food is allowed to pass into the intestines only after it is converted to a liquid soup. It remains a liquid soup until it reaches the colon where fluid is rapidly absorbed to form solid material. Fiber is found in all foods from plants. It is composed of sugar molecules bound together so tightly that humans lack the enzymes necessary to separate out individual sugar molecules. Only single sugar molecules can be absorbed into the bloodstream. Thus fiber cannot be absorbed so it passes to the colon in the liquid soup.

The fiber holds water in the colon and helps keep the stool from becoming so hard that it blocks the passage of gas formed in the colon. Pressure increases behind the hard stool, swelling the colon to cause outpouchings called diverticula. Seeds, nuts and other plant materials help to keep stool soft and prevent diverticula from forming. On the other hand, refined flour that has had the fiber removed cannot hold much water, so it causes hard stool that is more likely to obstruct the passage of gas and increase the chance that outpouchings will form in the colon.

"White Whole Wheat" Breads

2011-06-04T12:08:00.001-04:00

"White whole wheat" breads are made with flour ground from a variety of wheat that has a white outer covering, not brownish-red. That's why the flour is pale in color rather than light brown. So nutritionally it is equivalent to bread made from ordinary (brown/red) whole wheat. HOWEVER, when you grind ANY grain into flour, you lose a major benefit of whole grains -- see WHOLE Grains are Better than Any Flour.

Antioxidant Pills Reduce Exercise Benefits

2011-06-03T20:57:00.001-04:00

The current issue of Journal of the American College of Sports Medicine shows that antioxidant pills prevent the major mitochondrial benefits of athletic endurance training (Medicine & Science in Sports & Exercise, June 1, 2011). Rats that trained on a treadmill increased the enzymes that are necessary to increase the number and size of mitochondria. Rats who trained on a treadmill and were given two powerful antioxidants, vitamin E and alpha lipoic acid, did not increase the enzymes that are necessary to increase the number and size of mitochondria.

How humans get their energy for exercise: Humans convert food to energy most effectively in the mitochondria, hundreds of small chambers inside muscle fibers. They need oxygen to do this. The limiting factor to how fast and long you can move is the time it takes to move oxygen into muscle fibers. Athletic training makes you faster and gives you greater endurance by enlarging and increasing the number of mitochondria in muscles.

Antioxidant pills can harm: People who take 1000 mg/day of vitamin C and 400 IU/day of vitamin E do not gain the benefits of increased insulin sensitivity when they exercise (Proceedings of the National Academy of Sciences, May 12, 2009).

• When blood sugar levels rise too high, sugar sticks on the surface of cell membranes and can never get off. The attached sugar is converted in a series of chemical reactions to sorbitol that destroys cells.

• Contracting muscles help to prevent this damage by removing sugar so fast from the bloodstream that blood sugar levels do not rise too high.

• Food is converted to energy to power your muscles by a series of chemical reactions that shuffle electrons from molecule to molecule.

• This occurs primarily in the mitochondria, small energy-producing chambers in cells, that number anywhere from a few to thousands in each cell.

• As electrons are shuffled to produce energy, extra electrons can accumulate. They can either end up on hydrogen atoms to form water and become harmless, or they can end up on oxygen atoms to form free radicals that can damage cells. This can cause cancers, heart attacks and other life-shortening conditions.

• Exercise speeds up the reactions that turn food into energy, so exercise increases the production of free radicals.

• The body responds to this increased production of free radicals during exercise by producing tremendous numbers of antioxidants that sop up the free radicals and render them harmless.

• Exercise prolongs life and prevents heart attacks and cancers by causing the body to dispose of free radicals by the increased production of antioxidants.

Let the buyer beware: If you exercise and take antioxidant vitamins C and E, you prevent your own body from making large amounts of antioxidants during exercise, so more free radicals (oxidants) accumulate in your body and more cells are damaged.

Many studies show that:

• Taking large doses of beta carotene (pro-vitamin A) increases risk for heart attacks in men and increase risk for lung cancer in smokers.

• Taking large doses of vitamin C does not prevent colon cancer, and does not prolong life in people with cancer.

• Taking large doses of vitamin E or selenium does not prevent lung cancer, heart disease or stroke.

My recommendations: Exercise every day, and get the antioxidant vitamins and other nutrients your body needs from foods, not from pills. Eat a wide variety of foods including large amounts of fruits, vegetables, whole grains, beans, nuts and other seeds. If you want to take Recommended Dietary Allowances of vitamins in pills, go ahead; there is little evidence that you will harm yourself. However, when you take large doses of any vitamin, you don't have the foggiest idea whether you are harming or helping yourself. I do not recommend large doses of vitamins to anyone.

Heat Stroke and Hyponatremia

2011-05-31T20:27:00.001-04:00

The most likely cause of death during hot weather sports is heat stroke, when the body temperature rises so high that it cooks the brain (Medicine and Science in Sports and Exercise, July 2008). Nobody should ever die of heat stroke because your body sends you warning signals as your temperature rises. Those most likely to suffer heat stroke are those who have arteriosclerosis, are overweight or are in poor shape. The treatment for a person who collapses from heat stroke is immediate immersion in cold water.

In 1965, I almost died from heat stroke in an unimportant local race in Arlington, Virginia. I am still embarrassed by the stupidity that I showed when I ignored all of the warning signs as my temperature continued to climb.

Signs of impending heat stroke
First your muscles are affected, then your circulation and then your brain. As your temperature starts to rise, your muscles feel like a hot poker is pressing against them.

It is normal for intense exercise to make your muscles burn, but hard exercise does not cause painful burning that feels like fire. Furthermore, the burning of hard exercise is relieved by slowing down. The muscle burning of impending heat stroke does not go away when you slow down.

As your temperature rises further, the air that you breathe feels like it's coming from a furnace and no matter how rapidly and deeply you try to breathe, you can't take in enough air. When you exercise intensely, you can become very short of breath, but the air you breathe will not burn your lungs. Burning in your lungs, not relieved by slowing down, signals impending heat stroke.

When you feel that the air is so hot that it burns your lungs, stop exercising. This sign means that your heart cannot pump enough blood from your exercising muscles to your skin, so heat is accumulating rapidly and your temperature is rising rapidly. Your temperature is now over 104 and continuing to exercise will raise your body temperature even further and it will start to cook your brain.

Your head will start to hurt, you'll hear a ringing in your ears, you may feel dizzy, you may have difficulty seeing and then you will end up unconscious. Your temperature is now over 106 and your brain is being cooked just as the colorless portion of an egg turns white when it hits the griddle.

When does heat stroke occur?
Almost all cases of heat stroke occur when you suddenly increase the intensity of your exercise, such as the finishing sprint of a long distance running or cycling race, or an intense run down the field in soccer.

How body temperature can rise uncontrollably
An excessive rise in body temperature is caused either by producing too much heat or by inability to dissipate the extra heat. When you exercise, almost 80 percent of the energy that is used to drive your muscles is lost as heat. That means that the harder you exercise, the more heat you produce.

During exercise, more than 70 percent of the energy used to drive your muscles is lost as heat. Your heart has to pump extra blood from your hot muscles to your skin where you sweat. Sweat evaporates and cools your skin to dissipate the heat. The harder you exercise, the more heat your muscles produce. Everyone who exercises, particularly in hot weather, has to sweat to keep the body temperature from rising too high.

Drugs can cause heat stroke
Heat stroke is more likely to be caused by inability to get rid of heat than by producing too much heat. Stimulants such as amphetamines or cocaine can kill athletes by preventing them from getting rid of heat by blocking sweating and blood flow to the skin. A single nasal dose of cocaine can block blood flow to the skin and sweating, to prevent a person from cooling his own body (Annals of Internal Medicine, June 4, 2002).

Treatment
When a person passes out from heatstroke, get medical help immediately. Any delay in cooling can kill him. Carry the victim rapidly into the shade and place him on his back with his head down and feet up so blood can circulate to his brain. Cool him by pouring on him any liquids you can find or spray him with a hose. It doesn't make any difference what you pour on him: milk, Coca Cola, beer, or anything else. Evaporation of any liquid cools. As you cool him, he will then wake up and talk to you and act like nothing has happened. While he's sitting or lying there, his temperature can rise again and he can go into convulsions or pass out again, so he must be watched for at least an hour.

An athlete or exerciser who passes out from overheating should be immersed in cold water immediately to prevent brain and multiple organ damage. However, a heart attack can also cause a person to pass out and this should not be treated with cold water immersion. Therefore always get medical help immediately when you see a person pass out during exercise.

Prevention
Heat stroke is caused by continuing to exercise intensely in spite of all the warning signals that the body presents. Dehydration also increases your risk for heat stroke.

When you compete in sports, you need to drink before you feel thirsty, because you slow down and lose power long before you have any signals to tell you that you are dehydrated. In warm weather, trail runners raced 12 km (7.2 miles) much faster when they took fluids (Journal of Athletic Training, March-April 2010). With fluids, they averaged 53.1 minutes compared to 55.7 minutes without fluids. Immediately after the race, the dehydrated runners had signs of greater body stress such as heart rates six beats per minute faster and intestinal temperatures .22 degrees C higher.

Thirst is a late sign of dehydration
You won't feel thirsty during exercise until you have lost between two and four pints, or two to four pounds. Thirst is a very late sign of dehydration. You sweat during exercise, and since sweat contains much less salt than your blood, you lose far more water than salt during exercise. As blood salt levels rise higher and higher, they trip off special osmoreceptors in your brain to tell you that you are thirsty. Since it takes a long time for blood salt levels to rise high enough to tell you that you are thirsty, you will be severely dehydrated long before you feel thirst.

You need more sugar in hot weather
During long sports competitions, you need to take sugar as well as fluid because running out of sugar stored in muscles slows you down. The only mineral that you need to replace during exercise is common table salt. Water or your favorite drink plus food containing sugar and salt are just as effective as any sports drink to maintain endurance and prevent heat exhaustion. The best exercise drink is the one that tastes best to you, because that's what you will drink the most (International Journal of Sport Nutrition and Exercise Metabolism, January 2002).

Hyponatremia
Up to fifteen years ago, athletes were advised to drink as much as they could to insure that they did not lose any weight during endurance competitions. This caused a condition called HYPONATREMIA which has killed some novice cyclists, runners and athletes in other endurance sports. It occurs almost never in trained athletes because it is most likely to occur in people who slow down so much that they spend too much time drinking fluids and too little effort maintaining pace. During competitions, you work so hard to maintain pace that you have to conscientiously work just to drink enough.

How hyponatremia kills
Hyponatremia is caused by drinking too much fluid, not by excessive loss of salt in sweat or by the stress of exercising. The extra fluid expands blood volume and dilutes blood salt levels. This causes blood salt levels to drop too low, while brain salt levels remain normal. Fluid moves from an area of low salt concentration into areas with high salt levels, so fluid moves from the bloodstream into the brain, causing brain swelling. Since the brain is enclosed in the skull, which is a tight box, the brain expands and has nowhere to go, so it is squashed to cause headache, nausea, and blurred vision.

Blood tests only way to diagnose hyponatremia
Since the symptoms of hyponatremia are the same as those caused by pure dehydration with normal blood salt levels, the only way to diagnose the condition is with blood tests. As blood salt levels drop even lower, the person becomes confused, develops seizures and falls unconscious. You should suspect hyponatremia when the event takes more than four hours and the athlete has been drinking often during the event. Anyone who is confused, passes out or has seizures should be sent to a hospital immediately. Hyponatremia requires skilled management because the first impulse of an inexperienced physician is to give intravenous fluids, which dilute blood salt levels further, causing more brain swelling that can kill the patient.

How much fluid should you drink?
You will not become thirsty during exercise until you have lost between two and four pints of fluid, so you can't wait for thirst to encourage you to drink. Dehydration makes you tired and it is unlikely that you can replace the lost fluid during a race after you have become thirsty. The American College of Sports Medicine recommends a limit of 1200cc (5 cups, 2.5 pints, a little over 1 quart, or 2 average size water bottles) per hour, but for a person who is not exercising near his or her maximum, this could be too much (Clinical Journal of Sport Medicine, July-August 2005). A person exercising near his capacity and not slowed down by fatigue probably does not have to worry about limiting fluid intake. He is working so hard to maintain intensity that he doesn't have enough time to drink too much. On the other hand, people slowed down by fatigue or those who are out of shape should limit fluid intake, probably to less than two water bottles per hour.

Drink to avoid thirst
No studies show that forced drinking of fluids is any more effective than just drinking frequently to avoid thirst (Annals of Nutrition and Metabolism, November 2010). So current advice is to drink frequently, but just try to avoid feeling thirsty. You are in trouble with dehydration when you start to feel thirsty. Thirst is such a late sign of dehydration that once you feel thirsty, it is too late for you to catch up on your fluid needs during competition.