For those who follow these things, the Report Card is an extremely important (albeit depressing) document.  Reading the Report Card from year to year highlights all the ways that Canadian kids are becoming less active and more sedentary, and how little progress is being made in turning things around.

Here is a brief sample of this year’s release:

Among the 24 grades assigned in the Report Card, key grades include:

• “F” for Active Play & Leisure
• “F” for Physical Activity Levels
• “F” for Screen-Based Sedentary Behaviours
• “D+” for Active Transportation
• “D+” for Family Physical Activity
• “F“ for Federal Government Investments
• “C-” for Provincial/Territorial Government Investments

So clearly we’re not doing so well, which honestly isn’t a huge surprise.

But in addition to the “Grades” that the Report Card hands out every year, it also serves as a phenomenal resource for anyone looking for info on physical activity and/or sedentary behaviour among Canadian youth, as well as the investments that our society is putting into the promotion of healthy behaviours.  I’m pretty immersed in these topics at the moment, but the Report Card still finds incredibly useful data that I might have otherwise missed.

For example, I read one stat in this year’s press release that absolutely blew me away:

Canadian kids are spending seven hours and 48 minutes per day in front of screens, dramatically exceeding the guideline of no more than two hours per day.

That’s right – the average Canadian kid spends almost 8 full hours in front of a screen based device everyday.  I hadn’t heard the stat before so I went to the reference paper, which can be accessed for free here.

The data comes from the Canadian Youth Smoking Survey (YSS), which is a nationally representative survey of nearly 52 000 Canadians in grades 6-12 (when a survey is nationally representative, it means that the distribution of participants from various regions, ethnic and linguistic backgrounds match pretty closely with that of the nation as a whole).

What did they do?

From the paper:

The YSS asked respondents to report the average number of hours per day that they spent (a) watching TV or videos, (b) playing video games and (c) playing games or surfing the Internet on a computer. Respondents could choose from “none,” “less than 1 hour a day,” “1 to 2 hours a day,” “more than 2 hours a day but less than 5 hours a day,” or “5 or more hours per day” for each behaviour.

They then added up an individual’s responses in each category to get their total daily screen time (the author’s used the lowest value in each response category).  For example, if I said that I watch 1-2 hours of TV, 2-5 hours of video games and 5+ hours of surfing the internet, my total would be 8 (1+2+5).

What did they find?

More than 50% of Canadian kids get more 2 hours of screen time per day, which is the suggested guideline for children and youth (work in our lab has found that kids who exceed 2 hours of screen time per day tend to be less healthy both physically and mentally than those who get less than 2 hours per day of screen time, as detailed here).  Moreover, boys averaged 8.3 hours of screen time per day, while girls averaged 7.3 hours. So kids aren’t just getting a little more than the guidelines – they are getting a lot more.  And keep in mind if that average is around 8 hours per day, then that means that many kids are getting much more than that – a frightening thought.

The paper also looked to see how many kids were exceeding daily screen time recommendations in each region of the country (see below figure – I apologize for the size of the text on the figure – click on it to be taken to the paper itself to see it in full size).

From Leatherdale and Ahmed, 2011

The take-home message from the figure is that 52-55% of kids in Ontario, Quebec, and the Atlantic provinces exceed the screen time guidelines, compared to just 42-45% of kids in the Prairies and BC. Not that BC’s 42% is anything to write home about, but it’s still considerably better than the rest of the country.

Finally, screen time seemed to increase as self-esteem decreased.

Strengths and Limitations

This study has a big strength, and that is the fact that it’s nationally representative with a massive sample size.  But there is also a pretty big limitation – screen time was all self-reported.  In a study like this there is no way around that… but it’s still a limitation.  I find it hard to believe that the average kid gets 8 hours of screen time per day (keep in mind that this was all entertainment related screen time, and so shouldn’t include school work).  In order to get that much screen time outside of school hours, you’d need to be watching a screen for pretty much every single waking hour that you’re not in school.  That seems unlikely to me, at least when we’re talking about average amount of screen time per day.  Keep in mind that self-reported sedentary behaviour in kids doesn’t always match up well with objectively measured sedentary behaviour, as I’ve pointed out in the past.

It’s possible that the kids misunderstood the questions (e.g. they included all computer time in their answers, rather than just time playing video games and surfing the web), that they do some of these screen-related behaviours simultaneously (e.g. watching TV while also playing video games on a separate device – this issue has been discussed frequently by Mitch Joel), or maybe kids are just really bad at estimating how much time they spend in front of screens.  Or a combination of all three.

Be that as it may, this is still the best data we have on screen time among Canadian youth.  And since our screen time guidelines were created using this same type of self-report data,I think it’s still a valid way of assessing whether kids are exceeding them (which the majority of them are).  But if we could figure out a better way of objectively measuring screen time in a large study such as the YSS it would be a real step in the right direction.

What’s the take-home message?

Regardless of the precise number, Canadian kids are getting way too much screen time.  Given the multitude of physical and mental health conditions linked with excessive screen time in this age group, we really need to take action to get these numbers down considerably.

Finally, don’t forget to download yourself a copy of this year’s Report Card or related material (they also post helpful powerpoint slides, etc).  You can find it all at the Active Healthy Kids Canada website.

Travis

Leatherdale ST, & Ahmed R (2011). Screen-based sedentary behaviours among a nationally representative sample of youth: are Canadian kids couch potatoes? Chronic diseases and injuries in Canada, 31 (4), 141-6 PMID: 21978636

I’m sure there is going to be plenty of awesome sessions to attend at the conference, but I wanted to let people know about two events in particular.

1. SBRN Lunch Meeting

As regular readers of the blog will know I am a proud member of the Sedentary Behaviour Research Network (SBRN), which is the only organization focused explicitly on sedentary behaviour.  SBRN member Ernesto Ramirez has organized a lunch for anyone interested in sedentary behaviour, which will take place on May 31 at 11:30am at the Chieftan Pub (within walking distance of the conference).  The event is free (although you do need to pay for your own lunch), and open to anyone interested in sedentary behaviour.

If you’re planning on coming, please RSVP here so that we can make sure we have enough tables reserved.  So far we’ve got 13 folks signed up, and we’d love to have more.  There is no fixed agenda, just a chance to network with other people who are interested in the health impact of sedentary behaviour.

There were similar SBRN meetups at the recent ICDAM conference in Italy and at ISBNPA in Austin, Texas, and we’re hoping it continues at other events down the road.

2. My poster session – come say hello!

For anyone who is interested, my presentation takes place from 9:30-11:00am at session G-30 on June 2 (Poster Board # 50) and is titled “Acute Sedentary Behavior and Markers of Cardiometabolic Risk: A Systematic Review of Intervention Studies”.  As the title suggests, it will focus on our systematic review of the health impact of short bouts of sedentary behaviour. For those who are skeptical that a short bout of bed rest or sitting  could have a measurable health impact, you may want to check out this recent post on the topic.  The presentation will be based on this paper which is now in press at the Journal of Nutrition and Metabolism.

Here is the abstract from the paper itself (which is slightly updated from the presentation abstract):

North Americans spend half their waking hours engaging in sedentary behaviour. Although several recent interventions suggest that short bouts of uninterrupted sedentary behaviour may result in acute increases in cardiometabolic risk, this literature has not been reviewed systematically. This study performed a systematic review of the impact of uninterrupted sedentary behaviour lasting ≤7 days on markers of cardiometabolic risk (insulin sensitivity, glucose tolerance, and insulin, glucose and lipid levels) in humans. Interventions were identified through systematic searches of Medline and Embase, and screened by 2 independent reviewers. A total of 252 interventions were identified that examined the impact of imposed sedentary behaviour on biomarkers of interest. The majority of these studies focused on healthy young men, with very little identified research on females or other age groups. We found consistent, moderate quality evidence that uninterrupted sedentary behaviour ≤7 days results in moderate and deleterious changes in insulin sensitivity, glucose tolerance and plasma triglyceride levels. In contrast, there is inconsistent, very low quality evidence linking uninterrupted sedentary behaviour with changes in glucose tolerance, insulin, glucose, HDL- and LDL-Cholesterol levels. These findings suggest that uninterrupted bouts of sedentary behaviour should be avoided in order to prevent or attenuate transient increases in metabolic risk.

For info on all conference presentations, you can view the entire conference program here.

If anyone else is presenting at the conference, feel free to add your presentation title and details in the comments below so that people know how to find you.  Looking forward to seeing everyone in San Francisco!

Travis

PJ: What was the major finding of your study?

SP: Scientists have long assumed that the cause of diet-induced obesity in mice is nutritional; however, our discovery shows that the spreading of caloric intake through the day may contribute, as well, by perturbing metabolic pathways governed by the circadian clock and nutrient sensors. For decades, our society has focused on calorie in, calorie out, exercise and eat healthy, however, this is a novel study that has shown when we eat could be just as important as what we eat.

PJ: Can you briefly describe how the study was conducted?

SP: We put two groups of mice on different eating regiments for 100 days. Both groups ate a high-fat, high calorie diet. The first group was allowed to eat whenever they wanted, grazing throughout the day and night. The other mice had access to food only for eight hours at night, since mice are nocturnal. The results were astonishing. Despite consuming the same amount of calories everyday, the mice that ate on a restricted eight hours were nearly 40 percent leaner and showed no signs of inflammation or liver disease and had healthy cholesterol and blood sugar levels. The group of mice that nibbled day and night became obese, developed high cholesterol, high blood sugar, fatty liver disease and metabolic problems.

PJ: What is the implication of these findings to the average overweight individual?

SP: Our body is designed to undergo overnight fasting. For millions of years humans ate only during the day time. Only recently in the last 50 years our society began eating more at night, and during longer periods throughout the day. Much like our brain needs to rest at night, our data suggests that the stomach and the body’s digestive system need to rest from processing incoming fuel, otherwise we work our organs into a state of metabolic exhaustion. Imagine trying to perform major construction work on a busy highway in the middle of rush hour traffic? Our stomach and liver repairs itself every night, and consuming more food is similar to putting more cars on the road when repairs are being made. It causes a lot of chaos. Researchers may be overlooking the role that timing has on the body’s response to food.

PJ: What is a major limitation of your findings?

SP: The recent study is only conducted in mice. We dont even have an evidence-based measurement of when people eat or know whether eating too many hours correlates with predisposition to metabolic disease.

PJ: Does your research dispute the notion that many small meals throughout the day are the optimal strategy for weight loss or prevention of weight gain?

SP: Our study in mice suggests that an extended fasting time, allowing your stomach and liver to rest may prevent weight gain and metabolic diseases. It does not dispute the notion, as our mice on 8 h eating were still eating frequently.

PJ: What should be the follow-up study to this one? What remains unclear?

SP: Our research needs to be conducted in humans before we could definitively apply it to fight the obesity and diabetes epidemic. However, this study changes the paradigm of our focus on solely calorie-in and calorie out. It brings the notion that our body’s calorie use efficiency can be substanctially changed by eating pattern alone. The effect in humans is unclear. Wheter fasting can also reduce the harmful impact of high fructose and high carb diet needs to be tested. In mice, whether 10,12,14,16 h eating has similar effect also needs to be explored.

PJ: Thanks so much for sharing this fascinating work with us, Satchin.

Peter

Dr. Satchidananda Panda is an Associate Professor in the Regulatory Biology Laboratory at the Salk Institute. His research focuses on the effect of biological clock on behavior physiology and metabolism.

Reference: Hatori et al., Time-Restricted Feeding without Reducing Caloric Intake Prevents Metabolic Diseases in Mice Fed a High-Fat Diet. Cell Metabolism (2012) doi:10.1016/j.cmet.2012.04.019

This year we are sticking with the debate format, with the question being “Is Obesity A Disease?”.  Our presenters will be Dr Arya Sharma (Scientific Director of the Canadian Obesity Network, bariatric physician and a popular blogger) and Dr Jacqui Gingras (an Assistant Professor and Registered Dietitian in the School of Nutrition at Ryerson University, and an advocate of the Health at Every Size Approach).  The event will be moderated by Dr Mark Tremblay, Director of the Healthy Active Living and Obesity Research Group at the Children’s Hospital of Eastern Ontario Research Institute, and author of seminal papers charting the rising level of obesity in the Canadian population.

The debate will be broken into 3 subsections:

1. The health impact of obesity – does obesity cause increased health risk, or is it merely an innocent bystander?
2. The medicalization of obesity – how has obesity come to be viewed as a medical condition, and is this a good or bad thing?
3. Concluding statements: Should obesity be viewed as a disease?

Between each section there will be a moderated Q&A, with the hope being that the event is as much a discussion involving the audience as it is a debate between the panelists.

The event will be taking place from 7:30-9:30pm on June 7th at the Richelieu Vanier Community Centre in Ottawa.  Admission is free (although seating is limited on a first-come, first-serve basis) and refreshments will be provided.  For anyone coming by transit, the number 5 bus comes directly to the center from downtown Ottawa (there is also parking available on-site).  Feel free to print or distribute the posters for this event far and wide (I can provide a PDF version for anyone who would like one)

CIHR Poster

Where is the Richelieu Vanier Centre?

For details on how to find the Vanier Centre, please enter your details into the Google Map below.

View Larger Map

What to do if you don’t live in Ottawa?

As with last year’s debate, we will be making audio and video recordings of the event which will be posted online here at Obesity Panacea and elsewhere.  Unfortunately we won’t be able to livestream this event since there is no wifi at the venue, but we’ll do our best to get the recordings online as soon as possible.  And of course if anyone has a means to livestream video without wifi, I am always open to suggestions!

Also, feel free to submit your questions and comments for the presenters below, and we will do our best to introduce some of them at the debate.

Funding

Finally, we would like to thank CIHR for funding this event through the Cafe Scientifique program, the Canadian Obesity Network for providing additional funding support, and the HALO Group at the CHEO Research Institute for providing in-kind support.  And of course we are very thankful to our presenters and to the members of the CON Student chapter at the University of Ottawa for organizing what promises to be an excellent event.

Hope to see you on June 7th!

Travis

Image by waferboard

Hopeful news for the Canadians among us – Liberal MP Kirsty Duncan has introduced a motion calling on the government to take action on the extremely low levels of physical activity among Canadian children and youth.  Better yet, other Canadians can also help out.

Here are her motions from May 9th (emphasis mine):

M-371 — May 9, 2012 — Ms. Duncan (Etobicoke North) — That, in the opinion of this House, the government should recognize that: (a) evidence shows that physical inactivity is a major public health issue in Canada; (b) children and youth are getting an average of 6 hours per day of screen time outside of school hours, and over 7 hours on weekend days; (c) only 9 percent of boys and 4 percent of girls meet the Canadian Physical Activity Guidelines; (d) Canada remains without a national physical activity strategy; (e) in 2005 Canada’s federal/provincial/territorial ministers of health agreed to the Integrated Pan-Canadian Healthy Living Strategy; (f) in 2010, Canada’s ministers responsible for health declared that the promotion of health and the prevention of disease, disability and injury are priorities, necessary to the sustainability of the health system, and that there has been little follow-through on this declaration from the government; and (g) there is a disconnect between the government’s articulation of the importance of the childhood inactivity crisis, and its demonstrable leadership and investment.

M-372 — May 9, 2012 — Ms. Duncan (Etobicoke North) —That, in the opinion of this House, the government should immediately resume discussions with the provincial and territorial ministers responsible for health to develop a comprehensive pan-Canadian strategy to promote physical activity, commit to the resulting strategy, and make the necessary investments.

Here’s how others can help out:

I have embedded a petition below, which also calls on the Canadian government to take action against childhood inactivity.  If you feel strongly on this issue, please print the form and get at least 25 signatures from other Canadian citizens (they all need to sign on the form itself, no digital signatures or faxes).  Also feel free to embed the petition on your own websites, Facebook, etc.

Once you’ve got 25 signatures, send the petition to:

Ms Kirsty Duncan, MP
613 Confederation Building
House of Commons
Ottawa, ON
K1A 0A6

Petition May 8 2012

For those who prefer an online approach, you can join the “Canada needs a youth physical activity” Facebook page.

Why is this petition important?

Each time that Ms Duncan gets a petition with at least 25 signatures, it essentially buys her time in the Hours of Commons to read the concerns of the petitioners.  And the Government then has to respond to each petition.  The more petitions, the more times it gets brought up.  And hopefully if it gets brought up frequently enough, the government will take some action.

If you are working in an area related to physical activity (e.g. personal trainers, phys ed teachers, healthcare workers, parents, youth sport coaches, health researchers, etc) or if you simply care about physical activity, please consider printing the form and getting it signed by your friends and colleagues.

As an aside, I’m not promoting this petition as a partisan thing.  I’m not aligned with any political party, and would quite frankly be happy with any party that took physical activity and chronic disease prevention seriously.  So if you’d like to contact an MP from another party to get them on board, then please go ahead.  The more the merrier!

Why a petition about childhood physical activity?

Canadian children are not very physically active.  As the below figure illustrates, Canadian youth spend about 8.5 hours per day (more than half their waking hours) sitting down. They also spend more than 6 hours per day in front of TVs and other screen-based devices.  And only 7% of Canadian kids are meeting current physical activity guidelines (60 minutes of moderate or vigorous physical activity per day, on at least 6 days per week).  In fact, Canadian kids get so little vigorous physical activity that it is almost impossible to find in the below pie chart (look for the narrow purple slice at the top of the pie – that’s how much vigorous PA Canadian kids are getting on a daily basis!).

Source: Colley et al, Health Reports (2011)

Given the low level of physical activity and high level of sedentary behaviour among Canadian children and youth, it’s not surprising that the general fitness and health of this group has decreased substantially since the 1980′s, as we have discussed previously (and new evidence here).

So physical activity levels are very low, and indications are that the health of Canadian kids is heading downhill.  And yet, the Canadian government has no actual strategy for increasing physical activity levels in children and youth.  Ministers responsible for health declared disease prevention to be a priority necessary for the sustainability of the Canadian healthcare system in 2010, but there hasn’t been any action in the 2 years since (aside from the Fitness Tax Credit, which has not been much success in actually increasing physical activity levels, especially among those who need it the most).

So if you find any of this important, please print off and sign the petition, and join the Facebook page.

Travis

Exciting news – this week the Sedentary Behaviour Research Network published an updated definition of the terms “sedentary” and “sedentary behaviour” in French and English in the journals Applied Physiology, Nutrition and Metabolism and Movement & Sport Sciences – Science & Motricité.

In brief, the new definition states that to be engaging in “sedentary behaviour”, you must meet three very basic criteria:

1. You must be expending very little energy (≤1.5 Metabolic equivalents)
2. You must be sitting or lying down
3. You must be awake

Older definitions tended to focus exclusively on energy expenditure, which made it unclear whether certain activities (e.g. standing still, sleeping) were sedentary or not.  This new definition clarifies these issues.

But more broadly, why was there a need for a new definition for sedentary behaviour?

Well, because currently people use the term sedentary to describe a variety of things.  For example, some researchers use the term sedentary to refer to someone who is sitting down (that’s how I use it).  Other researchers refer to someone as sedentary simply because they are not getting enough exercise, even though they may spend little or no time sitting down.  The term “inactivity” is similarly used to describe these two separate and mutually exclusive situations.

The problem is that if you’re looking for research on sitting and other “sedentary behaviours”, a Pubmed or Google Scholar search brings back a bunch of irrelevant papers that are actually talking about the lack of physical activity.  And you might also miss relevant papers that are labeled using a term which is different than the one you are using. I’ve been involved in two separate systematic reviews looking at the health impact of sedentary behaviour in recent years, and this ambiguity in terms made things much more difficult and time consuming.

A similar example of this issue is the term “football”, which means one thing here in North America, and something completely different in the rest of the world.  If you search for “football” on Pubmed, you get some papers on American football, some others on Australian football, and some on what we North Americans usually refer to as soccer. Similarly, if you did a pubmed search for “soccer”, you might miss relevant papers that use the term “football” instead.  Either way, it makes it much more difficult to find relevant information, it wastes a tremendous amount of time trying to determine if papers are relevant, and it can ultimately lead to confusion over what a paper is actually talking about.

So, the members of the Sedentary Behaviour Research Network got together and created an updated definition of sedentary behaviour and inactivity, in both English and French:

English:

We suggest that journals formally define sedentary behaviour as any waking behaviour characterized by an energy expenditure ≤1.5 METs while in a sitting or reclining posture. In contrast, we suggest that authors use the term “inactive” to describe those who are performing insufficient amounts of MVPA (i.e., not meeting specified physical activity guidelines).

French:

Nous suggérons que les revues définissent de façon formelle le comportement sédentaire comme une situation d’éveil caractérisée par une dépense énergétique ≤1,5 METs en position assise ou allongée. En revanche, nous suggérons que les auteurs utilisent le terme « inactif » pour décrire les individus ayant un niveau insuffisant d’activité physique d’intensité modérée à intense (MVPA), c’est-à-dire, n’atteignant pas le seuil d’activité physique recommandé.

You can also access the full letter at the following links: English Letter / French Letter.

The definition has already been endorsed by the Canadian Society for Exercise Physiology and La Société Française des Professionnels en Activités Physiques Adaptées, and I would encourage other organizations in this field to do the same. Please cite the letter when defining sedentary behaviour in your papers, and please distribute it to other individuals who may find it useful.  Finally, please refer people to this definition when acting as a peer reviewer.

I’d like to give a huge thanks to the 52 SBRN members who participated in the drafting of the new definition and signed their names to the below papers (including many of the most well-known researchers in this area from around the world).  Thanks also to Drs Gilles Thoni and Jean-Philippe Chaput for translating the definition and accompanying letter into French.

And don’t forget that SBRN is free to join – just visit www.sedentarybehaviour.org.

The definition can be cited as:

Sedentary Behaviour Research Network (2012). Letter to the Editor: Standardized use of the terms “sedentary” and “sedentary behaviours” Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme PMID: 22540258

Travis