Fitness & Health with Dr. Gabe Mirkin

Protein for Muscle Recovery and Growth

2009-06-30T21:33:00.001-04:00

Many athletes believe that they can grow larger muscles by taking protein supplements rather than by eating protein in ordinary foods. However, protein powders come from food, and extracts cannot be more efficient than the foods from which they are extracted.

All athletes train by stressing and recovering. They take a hard workout, damage their muscles, feel sore the next morning, and then take easy workouts until the muscles heal and the soreness goes away. The athlete who can recover the fastest can do the most intense workouts. Eating a high carbohydrate-high protein meal within a half hour after finishing an intense workout raises insulin levels and hastens recovery (Journal of Applied Physiology, May 2009). Another breakthrough study reported in the same issue shows that taking the high protein-carbohydrate meal before lifting weights does not hasten recovery.

Carbohydrate in the meal causes a high rise in blood sugar that causes the pancreas to release insulin. Insulin drives the protein building blocks (amino acids) in the meal into muscle cells to hasten healing from intense workouts. Muscles are extraordinarily sensitive to insulin during exercise and for up to a half hour after finishing exercise, so the fastest way to recover is to eat a protein- and carbohydrate-rich meal during the last part of your workout or within half an hour after you finish.

You can use either plant or animal sources of protein; both contain all of the essential amino acids necessary for cell growth.

There is also good data that creatine loading helps muscles recover faster. You get creatine from fish, poultry or meat, or creatine supplements. Your body can also make creatine from three amino acids found in both plants and animals: methionine, arginine and glycine. However, you get higher blood levels from supplements or animal protein sources. We do not know if taking the larger amounts of creatine in supplements is better than the amount found in meat, poultry or seafood.

Hip Fracture Usually Requires Hip Replacement

2009-06-25T21:05:00.000-04:00

The most-feared injury among serious bicyclists is a broken hip. The femur hip bone is shaped like a shepherd's crook. The blood supply to the ball at the top of the hip bone comes in through the neck just below the ball. If the neck or ball are broken, the blood supply is usually shut off and the top of the hip bone dies. To prevent this from happening, fractures of the ball or neck of the hip bone are usually treated with immediate hip replacement. Try to avoid this drastic surgery by keeping your bones as strong as possible.

1) All exercise strengthens bones. Bicycling strengthens bones, but not as much as sports that exert greater forces on bones such as running or lifting weights. (Medicine & Science in Sports & Exercise, March 2009).

2) Exercise increases calcium absorption, which is necessary for strong bones. As I reported last week, even non-impact exercises such as swimming and cycling increase calcium absorption from the intestines by upregulating the calcium transporter genes. (American Journal of Physiology, Endocrinology and Metabolism, April 2009).

3) Those most likely to suffer broken bones during exercise are people who have low levels of vitamin D (Journal of Bone and Mineral Research, September 2006). When you lack vitamin D, ionizible calcium drops. This causes the parathyroid glands to put out large amounts of parathyroid hormone which takes calcium out of bones to weaken them and increase fracture risk.

4) High blood levels of parathyroid hormone (from vitamin D deficiency or any other cause) are a major risk factor for bone fractures during exercise (Bone, August 2005).

If you ever are unable to expose a few inches of skin to sunlight for at least 20 minutes four or five times a week, get a blood test called vitamin D3. If it is below 75 nmol/L, you need to take a vacation in a sunny place, or take at least 3000 IU of vitamin D per day until you can get some sunlight.

The Hygeine Hypothesis: Hot Debate

2009-06-22T18:02:00.002-04:00

The Hygiene Hypothesis proposes that you need to have certain infections to have a healthy immune system. If you are not infected with various common germs, your immunity does not have the chance to practice killing germs and learning the difference between invading organisms and your own cells. For example, does Helicobacter pylori, the bacteria that causes stomach ulcers, also prevent diseases such as eczema? Nobody knows. Being infected with Helicobacter is associated with decreased risk for eczema (Journal of Epidemiology & Community Health, July 2007), but it is also associated with an increased risk for asthma (Gut, May 22, 2008).

Your immunity protects you from certain infections by searching out and killing foreign germs in your body. It does this by attacking surface proteins on invading bacteria and viruses. However, your immunity is not supposed to attack your own cells, so it does not attack cells that have the same surface proteins that your cells have. It may attack your lungs and cause asthma instead of attacking the bacteria that causes stomach ulcers. Your immunity may get so active with Helicobacter infections that it may attack your own skin to cause eczema.

The Hygiene Hypothesis has not been proven. It is just a hotly debated theory among doctors; only time will sort out the conflict and tell us if Helicobacter stomach infections help your immunity protect you from other infections. More on Helicobacter pylori

Surgery for Blocked Arteries Questioned

2009-06-17T01:17:00.004-04:00

What should you do if your doctor tells you that you have blocked coronary arteries? A recent study shows that in people who have blocked arteries and diabetes, the chances of dying or having a major heart attack are the same whether they undergo surgical procedures (bypass or stents) or just take medication to treat cholesterol, blood pressure and diabetes. Death rate was also the same whether or not they took insulin (BARI 2D study, New England Journal of Medicine, June 10, 2009).

Patients who had bypass procedures had fewer heart attacks than those who had stents, even though both had the same chances of dying (also reported in the BARI-1 trial). I think that stents are less effective in preventing heat attacks because stents are foreign bodies placed in arteries that can increase chances of clotting, a major precipitating cause of heart attacks. That is why people with stents are given drugs to prevent clotting. Also, type 2 diabetics who were not given insulin had fewer blockages than those given insulin. I think that this is because high insulin levels constricts coronary arteries.

This is a very important study because the most common cause of a sudden heart attack is diabetes, and 80 percent of diabetics die of heart disease. More than one third of Americans will become diabetic and that number is projected to double by 2030.

If you have diabetes and blocked arteries, try to avoid surgery. If you need surgery, you may gain better protection from a bypass than from a stent. I also believe that you should try to control type II diabetes without insulin. Get a blood test called C peptide (which measures insulin production). If it is above one, try to avoid insulin. If it is below one, or you cannot get your HBA1C blood test (which measures cellular damage from diabetes) below 6.5, you may need insulin.

For everyone, I recommend: 1) A diet rich in fruits, vegetables, whole grains, beans, seeds and nuts. Restrict meat from mammals, and eat refined carbohydrates (sugar water and flour) only when exercising. 2) Exercise every day, and avoid overweight, smoking and more than two alcoholic drinks a day. 3) Keep blood levels of vitamin D3 above 75 nmol/L.

2009-06-17T01:17:00.001-04:00

What should you do if your doctor tells you that you have blocked coronary arteries? A recent study shows that in people who have blocked arteries and diabetes, the chances of dying or having a major heart attack are the same whether they undergo surgical procedures (bypass or stents) or just take medication to treat cholesterol, blood pressure and diabetes. Death rate was also the same whether or not they took insulin (BARI 2D study, New England Journal of Medicine, June 10, 2009).

Patients who had bypass procedures had fewer heart attacks than those who had stents, even though both had the same chances of dying (also reported in the BARI-1 trial). I think that stents are less effective in preventing heat attacks because stents are foreign bodies placed in arteries that can increase chances of clotting, a major precipitating cause of heart attacks. That is why people with stents are given drugs to prevent clotting. Also, type 2 diabetics who were not given insulin had fewer blockages than those given insulin. I think that this is because high insulin levels constricts coronary arteries.

This is a very important study because the most common cause of a sudden heart attack is diabetes, and 80 percent of diabetics die of heart disease. More than one third of Americans will become diabetic and that number is projected to double by 2030.

If you have diabetes and blocked arteries, try to avoid surgery. If you need surgery, you may gain better protection from a bypass than from a stent. I also believe that you should try to control type II diabetes without insulin. Get a blood test called C peptide (which measures insulin production). If it is above one, try to avoid insulin. If it is below one, or you cannot get your HBA1C blood test (which measures cellular damage from diabetes) below 6.5, you may need insulin.

For everyone, I recommend: 1) A diet rich in fruits, vegetables, whole grains, beans, seeds and nuts. Restrict meat from mammals, and eat refined carbohydrates (sugar water and flour) only when exercising. 2) Exercise every day, and avoid overweight, smoking and more than two alcoholic drinks a day. 3) Keep blood levels of vitamin D3 above 75 nmol/L.

Burning During Exercise Differs from Muscle Pain After Exercise

2009-06-11T21:40:00.000-04:00

The burning you feel in muscles during intense exercise is different from the burning and pain you feel after exercising. Burning during intense exercise is caused by the acidity from accumulation of lactic acid. When your muscles cannot get all the oxygen they need to convert food to energy during intense exercise, lactic acid accumulates in muscles, makes them more acidic, and the acidity causes a burning feeling. Excess lactic acid is cleared from the muscles within seconds after stopping exercise.

Lactic acid is good because it is the most efficient fuel for muscles during exercise. It requires less oxygen for energy than virtually all other fuels. Sodium bicarbonate (baking soda) neutralize lactic acid in muscles during intense exercise and helps athletes to exercise longer (Medicine & Science in Sports & Exercise, October 2006). Caffeine (the amount in four cups of coffee) reduces muscle burning during intense exercise (International Journal of Sport Nutrition and Exercise Metabolism, April 2009). More on lactic acid

Burning or pain eight to 24 hours after exercising is usually caused by damage to the muscles themselves. The longer you stay in the burn during exercise and the greater the force on your muscles during exercise, the greater the muscle damage. Most athletes train by taking a hard workout on one day, damaging their muscles and feeling sore on the next, and then going at low intensity for as many days as it takes for the soreness to disappear. When muscles heal from hard force on them, they become stronger. Athletes recover from hard exercise actively by exercising at low intensity. They rarely take days off. Exercising at low intensity during recovery makes muscles more fibrous which protects them from injury when they are stressed again.

Which Blood Pressure Number is More Important?

2009-06-07T21:57:00.001-04:00

The higher number (systolic) measures pressure when your heart contracts, and the lower (diastolic) reading measures the pressure when your heart relaxes. A recent study followed people with high blood pressure to see which people developed heart attacks (Hypertension, May 26, 2009). The authors found that the best predictors for future heart attacks are the systolic (heart contraction) blood pressure and pulse pressure (the difference between systolic and diastolic blood pressures). Evidently the higher your blood pressure rises when your heart contracts, the more likely you are to have a heart attack. Normally, the aorta is supposed to widen when the heart contracts to send a large amount of blood to your arteries. Those with the stiffest arteries that do not widen with each heart contraction are the ones most likely to suffer heart attacks. More on interpreting your blood pressure numbers

Older People Need More Sunshine

2009-06-01T22:27:00.001-04:00

A study from the University of Warwick in England shows that more time in the sun can help older people avoid diabetes and heart attacks (Diabetes Care, July 2009). They evaluated 3,262 people aged 50-70 years old in Beijing and Shanghai, China, and found that 94 percent were low in vitamin D and 42 percent of those had metabolic syndrome: abdominal obesity, high triglycerides, low HDL and high blood sugar levels. This is consistent with world- wide studies that show that as people age their skin atrophies, reducing their ability to make vitamin D from sunlight. Seniors also usually exercise less so they do not go outside as often. Since they are more susceptible to cold, they usually wear more clothing when they do go outside. Inadequate vitamin D increases risk for heart attacks, strokes, certain cancers, arthritis, auto-immune diseases and many other health problems.

A major function of vitamin D is to increase absorption of calcium from food. When vitamin D levels are low, body levels of ionized calcioum drop. This forces the parathyroid glands to increase production of parathyroid hormone that blocks insulin receptors, to raise blood sugar levels markedly and increase production of insulin. High levels of insulin constrict coronary arteries to cause heart attacks.

Vitamin D deficiency occurs when the concentration of D3 (25-hydroxy-vitamin D) is less than 75 nmol/L. If you are deficient, you need to expose skin to more sunlight or take at least 2000 IU of vitamin D3 per day. To address skin cancer concerns, protect the most frequently exposed areas, since it is cumulative life-long exposure to sunlight that increases risk for skin cancer. For most people, this means you should use sunscreen or wear clothing to cover your face, scalp, neck, tops of the ears, forearms and hands whenever you will be in the sun for more than 30 minutes.
More on vitamin D

Drop in Performance? Common Causes

2009-05-31T08:14:00.001-04:00

1) The most common cause of a drop in performance in cycling, or any other sport, is overtraining: going hard when you should go easy. Hard-and- easy refers to intensity (speed and pressure on the pedals), not to total mileage. On one day, you ride very fast with your group, feel sore on the next day and go slowly for as many days as it takes for the soreness to go away. When the soreness goes away, you ride fast again. If you take hard workouts while your muscles are still sore you can cause chronic muscle soreness.

2) A second cause is a low-salt syndrome caused by sweat loss. The only mineral that you need in large amounts is sodium, common table salt. All athletes have to salt food heavily and use lots of salt. Your doctor can check for low-salt syndrome by having you take a very hard workout on one day, replenish your fluids, and then draw blood for sodium and chloride on the next morning. If you are worried about developing high blood pressure, check your blood pressure frequently.

3) The third most common cause is lack of vitamin D. Blood levels of vitamin D3 below 75 nmol/L can cause muscles to feel sore, particularly in the wintertime.

4) You can also fail to recover adequately from intense workouts if you do not carbohydrate- and protein-load within a half hour after you finish a workout. Your muscles are maximally sensitive to insulin during exercise and for up to a half hour after you finish exercising. Sugar taken within a half hour after you finish your intense workout will raise your blood sugar level enough to increase insulin levels. Insulin then drives protein into cells to help you recover faster.

5) Another cause of muscle soreness is not getting off your feet after intense workouts. Muscles recover fastest when they are not used. After intense workouts, lie down instead of sitting, standing or walking.

If you have had a marked drop in performance in your sport and none of these causes applies to you, you may need a medical evaluation.

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Muscle Soreness, Exercise Injuries and Vitamin D

2009-05-13T21:15:00.000-04:00

When doctors don't know the cause of a patient's problem, they often give it a fancy name so you will believe they are giving you a useful diagnosis. A perfect example of this is "idiopathic inflammatory myopathy", which means you have chronic muscle soreness and your doctor doesn't know why. Researchers recently reviewed the effects of exercise on people with chronic muscle soreness and found that exercise is beneficial (Current Opinion in Rheumatology, 04/07/09):
• The muscles of many of subjects with this condition did not get a sufficient oxygen supply
• Exercise increases endurance-type fibers after a 12-week exercise program
• Creatine supplements plus an exercise program are more beneficial than exercise alone
• Intensive resistance training improves muscle strength and endurance
• Exercise reduces muscle soreness and possibly even muscle inflammation

I am now convinced that a leading cause of muscle soreness and slow-healing injuries is lack of vitamin D. All my life, I have suffered a series of baffling injures that usually occur in the winter and heal in the summer. For the entire winter of 2007-8, I was unable to exercise because of a non-healing hamstring injury and diffuse muscle soreness. Eventually I found that my vitamin D 3 level was 22 nmol/L (normal is greater than 75). I took the prescribed treatment of 50,000 IU of vitamin D twice a week and my muscles became so sore that I couldn't even walk. In the summer, the hamstring injury healed and the soreness disappeared. This winter I went to Florida and was able to train on my bicycle better than ever. In March I went back to wintery Maryland and the non-healing hamstring injury and soreness reappeared. This time I improved within 24 hours of taking 2000 IU of vitamin D twice a day. From my experience, I conclude that:
• my muscle soreness and non-healing injuries are caused by or worsened by low levels of vitamin D
• very high doses (50,000 IU) may increase muscle soreness
• lower doses of vitamin D (2000 to 4000/day) or daily sunlight exposure cured my muscle soreness and helped to heal my injuries

Dr. John Cannell of the Vitamin D Council quotes 14 studies that show that athletic performance improves in the summer months when sunshine is abundant, or with ultraviolet light exposure in winter.

If 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.

Fructose More Likely than Glucose to Cause Diabetes

2009-05-10T22:26:00.001-04:00

Sugared drinks are fattening because the human brain does not recognize liquid sugar as calories to make you eat less food. We get our sugar in drinks in three forms: glucose, fructose and sucrose (glucose and fructose bound together in a single molecule). Now a report from the University of California Davis shows that taking in too much fructose increases your risk for diabetes and heart attacks (Journal of Clinical Investigation, May 2009). Thirty-two overweight men and women drank 25 percent of their daily energy requirements in either fructose or glucose- sweetened drinks. In 12 weeks, both groups gained similar amounts of weight, but the people taking fructose-sweetened drinks had higher triglycerides and more abdominal fat, and were more resistant to insulin. All three factors precede diabetes which markedly increases risk for heart attacks.

The subjects were fed drinks that contained only glucose or fructose, so this study will not help you make good beverage choices. Virtually all sweetened beverages contain both fructose and glucose. Soft drinks sweetened with high fructose corn syrup have 55 to 58 percent fructose, while fruit juices and beverages sweetened with table sugar contain equal parts fructose and glucose. I recommend the following:

1) Take sugared drinks only when you are exercising or within a half hour of finishing exercising. All sugar-sweetened beverages increase risk for insulin resistance (Archives of Pediatric and Adolescent Medicine, April 2009). Contracting muscles are exquisitely sensitive to insulin and therefore help protect you from the high rise in blood sugar that causes the liver to make triglycerides, that block insulin receptors that cause the pancreas to release huge amounts of insulin that causes fat to be deposited in the belly.

2) When you are not exercising, quench your thirst with water or non-calorie beverages. Eat whole fruits rather than taking in your sugar in drinks. Fruit with its pulp does not cause as high a rise in blood sugar as do sugared drinks (including fruit juices). The higher your blood sugar rises, the more sugar sticks to the surface of cells, causing cell damage. An orange satisfies your daily requirement for vitamin C, has 2.8 grams of fiber and 64 calories from 17 grams of sugar. More on preventing diabetes

Caffeine Reduces Muscle Burning During Intense Exercise

2009-05-07T12:54:00.001-04:00

Researchers at the University of Illinois report that 300 mg of caffeine (the amount in four cups of coffee) reduces muscle burning during intense exercise in both regular coffee drinkers and in those who do not drink coffee at all (International Journal of Sport Nutrition and Exercise Metabolism, April 2009). One of the researchers, Robert Motl, PhD, says that caffeine blocks spinal nerves that transmit pain messages to the brain. This means that people can exercise longer because they feel less pain.

Athletes take caffeine because they know it helps them to exercise longer. When muscles run out of their stored muscle sugar, they have to burn more fat which requires more oxygen. Lack of oxygen is the limiting factor in how fast and hard you can exercise over long periods of time. When you run low on oxygen, lactic acid accumulates in the muscles, which makes muscles more acidic, causing the burning that you feel in tired muscles. However, caffeine helps to delay the burning by causing muscles to burn more fat so they can preserve the sugar stored in muscles and you can exercise longer without accumulating large amounts of lactic acid.

Another interesting study from Iran showed that omega-3 fatty acids lessened delayed onset muscle soreness that occurs 48 hours after exercise in untrained men (Clinical Journal of Sport Medicine, March 2009).

Why Meat from Mammals is Risky

2009-04-13T12:09:00.000-04:00

A study of more than 500,000 Americans over 40 shows that those who consume the equivalent of at least a hamburger a day have a 30 percent increased chance of dying during the next 10 years, mostly from heart disease and cancer. Cold cuts, sausage and other processed meats also increased the risk (Archives of Internal Medicine, March 2009). This agrees with many other studies showing that eating meat from mammals is associated with increased risk for heart attacks, arthritis, and several types of cancer. The study found that eating fish, chicken, turkey and other poultry decreased the risk of premature death.

Most authorities still attribute the high mortality in meat eaters to the saturated fats and cholesterol in meat. This makes little sense since 1) poultry is also a rich source of saturated fats and does not increase premature death, cancer or heart attacks; 2) people who eat a diet rich is saturated fats from palm, palm kernel and coconut oils are not at increased risk for premature death; and 3) eggs and shell fish are extremely rich sources of cholesterol and they are not associated with premature death. I believe that the most likely explanation for the increased risk for heart attacks and premature death in meat eaters is inflammation from the glycoprotein Neu5Gc; see my reports from November 9 and November 16, 2008

High Insulin = High Breast Cancer Risk

2009-04-08T21:08:00.002-04:00

Women who have high levels of insulin are at high risk for developing breast cancer (Journal of the National Cancer Institute, January 2009). Insulin stimulates breast cells to grow. Women who are most likely to have high levels of insulin are those who are obese, store fat primarily in their bellies, do not exercise, eat lots of refined carbohydrates (sugar and flour), and lack vitamin D. Furthermore, people with diabetes who get cancer are 40 percent more likely to die earlier than cancer patients who are not diabetic (Journal of the American Medical Association, February 2007). Dr. Frederick Brancati of Johns Hopkins University in Baltimore combined the results of 23 studies involving about 125,000 people in 10 countries including the United States, Australia and the Netherlands. People with high blood sugar levels are at increased risk for cancers of the uterus, breast, colon, pancreas, endometrium, liver and bladder. Those with diabetes have a 76 percent higher risk of death from cancer of the uterus, a 61 percent higher risk for breast cancer, and a 40 percent increase for colon cancer. Furthermore, diabetics are at higher risk for heart disease, stroke, kidney damage and blindness.

Hard exercise should not reduce libido

2009-04-05T20:46:00.003-04:00

If hard exercise or training causes you to lose interest in making love, get a medical check-up. If your doctor finds nothing wrong with you, you may be training too much. Most endurance athletes have normal blood levels of the male hormones, testosterone and dihydro-testosterone, and lose neither sexual desire nor sexual performance (Journal of Endocrinological Investigation, October 2008).

Endurance athletes who have low levels of testosterone usually have normal blood levels of LH and FSH, the brain hormones that control testicular production of testosterone. Defective testicular production of testosterone is usually associated with very high levels of brain hormones. That means that reduced sexual desire associated with endurance training is governed by the brain, not testicular damage, and is often part of an overtraining syndrome.

Training for competition is done by taking an intense workout on one day, feeling sore on the next, and going at reduced intensity for as long as it takes for the soreness to go away. Taking intense workouts when you feel soreness causes muscle injuries and fatigue that affects all your organ systems, including your sexuality. Once you develop an overtraining syndrome, it can take a very long time to recover. If this has happened to you, I recommend jogging slowly each day and stopping each workout immediately when your legs feel heavy or sore. When you feel better, you can start to train intensely again, but be sure to include slow recovery days in your training program.

Who should restrict salt? (and who should not?)

2009-04-02T19:27:00.001-04:00

Most doctors recommend salt restriction for all their patients, even though many will not develop high blood pressure from high-salt intake and some may even be harmed if they restrict salt. Heavy exercisers lose so much salt that they have to take in lots of salt just to replace what they lose through sweat.

A study from China shows that people with metabolic syndrome are the ones who are most likely to develop high blood pressure from a high-salt diet and that high levels of insulin may cause the rise of blood pressure that is associated with increased salt intake (Lancet, published online March 2, 2009). Metabolic syndrome occurs when a person's cells lose their ability to respond adequately to insulin and blood levels of sugar rise too high. It is caused by eating too much refined carbohydrates, being overweight, not exercising, and lacking vitamin D and is characterized by storing fat primarily in the belly, having a thick neck, high blood triglycerides, low blood good HDL cholesterol, high blood sugar, and eventually liver damage and all the side effects of diabetes. People with metabolic syndrome had a greater rise in blood pressure with increased salt intake and drop in blood pressure with salt restriction. The more risk factors for metabolic syndrome a person had, the greater the rise and fall of blood pressure with changes in salt intake.

If you are concerned about your blood pressure, you can buy an inexpensive wrist cuff and check your blood pressure at bedtime. If it is below 120, you do not need to restrict salt. If you store fat primarily in your belly rather than your hips, your HDL is below 40, your triglycerides are above 175, or you have a blood sugar above 100 two hours after a meal or an HBA1C above 5.9, you probably should restrict salt and definitely should work to correct the causes of metabolic syndrome (described above).

Prolong life with exercise after age 50

2009-03-30T21:15:00.002-04:00

Men who start or increase their exercise programs after age fifty live longer than those who remain at their present activity levels, according to a study in the British Medical Journal (March 2009). More than 2200 men were checked at ages 50, 60, 70, 77 and 82 years. The greater the increase in exercise duration over that span, the longer their lives were extended. The reduction in early death from increasing exercise was the same as for men who stopped smoking.

Lack of exercise is associated with obesity, diabetes, heart attacks, strokes, osteoporosis, and cancer. Exercising regularly more than halves your chance of dying prematurely (Archives of Internal Medicine, December 2007). Yet more than 50 percent of North Americans do not exercise.

Exercise prevents disease and increases life span by many mechanisms. The major benefit probably comes from the contracting muscles themselves. A high rise in blood sugars and fats after meals damages cells. When blood sugar levels rise too high, sugar sticks to the surface of cell membranes. Once there, it can never get off, eventually killing the cells and leading to blindness, heart attacks, strokes and the other consequences of uncontrolled diabetes. Contracting muscles draw sugar and fat so rapidly from the bloodstream that they usually prevent blood sugar levels from rising too high. This effect is maximized during exercise. The effect is maintained for about half hour after you stop exercising and gradually tapers off until it disappears after about 18 hours. That explains why you get maximum benefit by exercising every day (rather than three times a week), and why greater benefit is gained by exercising more intensely for longer durations. How to start an exercise program

Can't lose weight? New research on thyroid may solve your problem

2009-03-23T20:45:00.002-04:00

Diets rarely help people to lose weight permanently, so exercise gives you your best chance to lose excess weight and keep it off. However, some people cannot lose weight, no matter how much they exercise. Researchers at the University of Pittsburgh showed that overweight people who do not lose weight when they follow an exercise program are likely to suffer from low thyroid function, and therefore should be able to lose weight if they take thyroid hormones (Medicine & Science in Sports & Exercise, February 2009). I think this is a very important study so this issue of the eZine is a little longer than usual.

When you eat, blood sugar levels rise. Your pancreas responds by releasing insulin into your bloodstream which drives sugar into cells where it can be used for energy. As you gain weight, fat cells fill with fat. This blocks insulin receptors so your cells cannot respond adequately to insulin and blood sugar rises to higher levels. This causes your pancreas to release even more insulin. Too much insulin can harm you. It acts on your brain to make you hungry, eat more and gain more weight. It constricts the arteries leading to your heart to cause heart attacks.

As I explained last week, muscles become extraordinarily responsive to insulin when you exercise so you need far less insulin to drive sugar from your bloodstream into cells. Insulin levels go way down with exercise, but the effect gradually tapers off in about 18 hours. So you have to exercise every day to maintain the benefit of lowered insulin levels, and overweight people who exercise every day usually lose weight.

However, some overweight people cannot lose weight no matter how much they exercise. This study shows that many of these people have low thyroid function which prevents the cells from responding to insulin and drives both insulin and blood sugar to very high levels.

Doctors do not diagnose low thyroid function by measuring thyroid hormone levels. Instead, they do a blood test called TSH that measures the brain's response to thyroid hormone levels. The brain produces TSH to stimulate the thyroid gland to make more thyroid hormone. TSH rises to high levels when the brain senses that there is not enough thyroid hormone in the body.

For many years, doctors have argued among themselves whether to treat people who have normal levels of thyroid hormones and very high levels of TSH (called subclinical hypothyroidism). This exciting new study shows that people who have high levels of TSH but have normal levels of thyroid hormone have muscles that do not respond to insulin adequately when they exercise. This means that they develop high levels of insulin and blood sugar, become overweight, diabetic, and often die of heart attacks.

If you are person who has extreme difficulty losing weight, ask your doctor to draw a blood test called TSH. If it is above 3.0, you probably will benefit from taking thyroid hormone. However, you must be careful not to take too much because overdoses of thyroid cause osteoporosis. Your thyroid dose should be adjusted to keep your TSH values between 0.3 and 3.0. Free weekly Fitness & Health eZine

Bone Density May Not Measure Bone Strength

2009-03-15T21:03:00.002-04:00

A study from Manchester Metropolitan University in the UK shows that sprint cyclists have denser bones than long distance cyclists who have denser bones than sedentary control subjects (Medicine & Science in Sports & Exercise, March 2009). While cyclists have less dense bones than weight lifters and football players, they still have denser bones than people who do not exercise. The greater the force on bones during exercise, the denser the bone. So any type of exercise is good for your bones and a sedentary lifestyle is bad for bones.

When I reported on this study, several readers responded by quoting other studies that showed competitive cyclists have lower bone mineral density in their spines than moderately-active, aged-matched men (Medicine & Science in Sports & Exercise, February 2009; Osteoporosis International Reports, August 2003). These studies have been interpreted to mean that cycling increases risk for bone fractures beyond what you would expect from just falling off the bike.

I cannot find any studies showing that cycling weakens bones to increase fracture risk. Bone density is associated with bone strength, but does not measure it. The only way to measure bone strength is to see how much force it takes at break a bone. For example, birds have strong bones that are not very dense.

The theory that the act of cycling weakens bones flies in the face of our current understanding of bone metabolism. If indeed cyclists suffer from weak bones (and I do not believe that they do), the cause would be something other than riding a bicycle. Bones are constantly remodeling. Cells called osteoblasts bring in calcium to bones while cells called osteoclasts take calcium out. Any force on bones increases, and lack of force decreases, the rate of bone formation. Astronauts in space lose bone because lack of force blocks their ability to respond to Insulin Like Growth Factor-1 that stimulates bone growth (Journal of Bone and Mineral Research, March 2004). All competitive cyclists know that hammering on the pedals while pulling up on their handle bars puts tremendous force on every muscle and bone in their bodies, and this should stimulate bone growth.

Weight Training Benefits the Heart

2009-03-08T10:20:00.001-04:00

Most authorities recommend both endurance and resistance exercise for heart health, even for people who have recovered from heart attacks. Now a study from The University of Athens in Greece shows how resistance exercise may help prevent heart attacks (Medicine & Science in Sports & Exercise, February 2009). Nine healthy, untrained male volunteers performed leg presses, with eight sets of six repetitions and three-minute rest intervals. One day later their blood fat levels were lower than normal after a high-fat meal. This shows that a single bout of weight lifting can prevent a high rise in blood fats one day later. A high rise in fat or sugar after meals increases risk for heart attacks. Exercising and exercised muscles help to remove sugar and fat from the bloodstream and this effect can last as much as twenty-four hours.

Diabetes Can Be Prevented and Cured

2009-02-27T08:31:00.001-05:00

In 2007, 233,619 Americans died from diabetes. 60 percent of the U.S. population over 65 suffers from diabetes or pre-diabetes and most have not even been diagnosed (Diabetes Care, February 2009). Four important reports should spur you to act if you have any of the risk factors for diabetes: “Diabetes Doubles Your Chances of Suffering from Dementia” (Diabetes, January 2008); “HBA1c Test Predicts Which Diabetics Will Lose Brain Function” (Diabetes Care, February 2009) “Rigorous Workouts Lasting as Little as Three Minutes May Help Prevent Diabetes by Helping to Control Blood Sugar” (BioMed Central Endocrine Disorders, February 2009); and “Exercise Capacity Predicts Which Diabetics Are at High Risk for Dying Prematurely” (Diabetes Care, March 2009).

If you have any combination of the following risk factors, suspect that you may be diabetic and check with your doctor:
* store fat predominantly in your belly, rather than your hips
* family history of diabetes
* overweight
* exercise less than three times a week
* high blood pressure
* HDL cholesterol lower than 40 mg/dL
* triglyceride level greater than 150 mg/dL
* history of diabetes during pregnancy or birth to a 9-pound baby
* thick neck
* polycystic ovary syndrome
* dark, thick skin around neck or armpits
* history of blood vessel disease to heart, brain, or legs
* HBA1C greater than 5.8
* fasting blood sugar greater than 100
* sugar two hours after eating greater than 100
* member of a high-risk ethnic population (e.g., African-American, Hispanic/Latino- American, American Indian, Alaskan Native or Pacific Islander)

You can become non-diabetic by losing weight, exercising, avoiding refined carbohydrates, and treating vitamin D deficiency so D3 blood test is greater than 75 nmol/L. More on diagnosis and treatment of diabetes

Heart Attack Prevention: More than Cholesterol

2009-02-11T21:18:00.001-05:00

Seventy-two percent of patients admitted in American hospitals for their first heart attack have blood cholesterol levels in the normal range (American Heart Journal, January 28, 2009). This means that the cholesterol guidelines are missing the majority of patients who have heart attacks because either 1) the guidelines are not low enough or 2) something other than a bad LDL cholesterol is causing most heart attacks in the United States.

Many good studies support the present guidelines that everyone should get their bad LDL cholesterol below 100. However, it now appears that some other risk factor must be affecting many people who suffer heart attacks. In November 2008 I reported on the Jupiter study which showed that statin drugs caused people with normal cholesterol but with high C-reactive protein levels to suffer 54 percent fewer heart attacks, 48 percent fewer strokes, 46 percent fewer angioplasties or bypass operations and 20 percent fewer deaths from any cause than those taking placebos (NEJM, November 9, 2008). Statins are known to reduce inflammation as well as to lower LDL cholesterol. A C-reactive protein test (CRP) measures inflammation. Inflammation is caused by anything that keeps your immunity active such as chronic infections or anything that damages tissue such as smoking, having high cholesterol or high blood pressure.

I also reported a theory to explain why eating mammal meat causes inflammation and is associated with increased risk for premature death, cancers and heart attacks. Meat contains a molecule called Neu5Gc that humans do not have, so the immune system of humans attacks this protein as if it was an invading germ and eventually attacks the host itself to destroy the blood vessels and increase risk for heart attacks and strokes. On the basis of this theory I strongly recommend avoiding meat from mammals, including beef, pork and lamb. Today, the best strategy for avoiding a heart attack includes lowering LDL cholesterol by avoiding saturated and partially hydrogenated fats and refined carbohydrates; and eating plenty of fruits, vegetables, whole grains, beans, seeds and nuts. Reduce inflammation by treating chronic infections and high blood pressure, avoid being overweight, smoking and eating meat. Exercise regularly, and work up gradually to a program that includes some intense exercise. Your doctor may recommend statins both to lower cholesterol and to control inflammation.

Exercise Protects against Inflammation

2009-01-24T11:39:00.000-05:00

Researchers from Ataturk University in Turkey showed that hard exercise protects you from inflammation by raising blood levels of the antioxidants superoxide dismutase, glutathion peroxidase and glutathione S-transferase (The Journal of Sports Medicine and Physical Fitness, September 2008). During vigorous exercise, food exposed to oxygen is converted to energy by transferring electrons from one chemical to another. If the transferred electron ends up on hydrogen, it is converted to water and is harmless. If it ends up on oxygen, it forms free radicals that can damage your genetic material and cause cell damage. To protect you, your cells produce antioxidants. Exercise protects you from free radicals by causing your cells to produce large amounts of antioxidants.

Greater Endurance with Aging

2009-01-20T22:38:00.001-05:00

I’m 74 years old and ride my bicycle more than 200 miles per week, often in pace lines with younger riders. I have noticed that younger riders can easily pull away from me in short bursts, but I keep coming back on them and seem to be better able to keep up with their accelerations as the ride progresses.

The latest issue of Exercise and Sports Sciences Reviews (January, 2009) reviews the entire world’s literature to show that endurance improves as you age. Wow!

The maximal muscle contraction force occurs when you do a single muscle contraction with all your might. Even though older people are not as strong as younger ones, many studies show that they can retain maximal force after many contractions far longer than younger people can.

Here’s the theory and evidence to explain why aging improves endurance. Muscles are made up of millions of individual fibers just as a rope is made up of many different threads. Each muscle fiber is enervated by a single nerve. As you age, you lose nerves throughout your body and when you lose the nerve that enervates a specific fiber, you also lose that muscle fiber.

Muscle fibers are classified as type I endurance fibers and type II strength and speed fibers. With aging, you lose far more nerves that enervate the strength and speed fibers than those that enervate the endurance ones. So, with aging, you lose strength but you retain a greater proportion of endurance fibers.

Muscle fatigue comes from the accumulation of waste products that occurs while food is converted to energy to power your muscles. Scientists can measure fatigue by measuring the accumulation of acid (H+), Phosphate (Pi) and protonated phosphate (H2PO4) in muscle. With the same percentage of their maximal muscle force, older people accumulate far lower levels of these end products than younger people do. Therefore even though older people are weaker, they can maintain their forceful contractions far longer than younger people can and they have greater endurance. This exciting recent data will encourage me to train even harder.
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Cold or Fever: Should You Exercise?

2009-01-18T21:20:00.000-05:00

Exercise may actually be beneficial when you have a cold. However, it's probably better to stop exercising altogether if you have a fever with aching muscles. When you exercise, your heart has to pump blood to your muscles to supply them with oxygen. It also must pump blood from your muscles to your skin where the heat is dissipated. When you have a fever, your heart has to work harder to get rid of extra heat.

You risk injury if you exercise when your muscles hurt at rest. When muscles are damaged, they release enzymes from their cells into the bloodstream and they fill with blood from broken blood vessels. One study reported markedly increased muscle damage during relatively minor exercise during an infection, with blood tests showing increases in muscle enzymes and ultrasound tests demonstrating hemorrhage into the muscles. You will not lose much conditioning if you take off a few days.