Time to sever the link between inactivity crisis and obesity epidemic?

Two weeks ago our colleague Dr Arya Sharma published a very interesting post discussing the latest reports on the extremely low levels of physical activity in the Canadian population (sometimes referred to as the “inactivity crisis”).  The gist of the reports are that exceedingly few Canadians (7% of kids and 15% of adults) are meeting physical activity guidelines.  But Dr Sharma’s argument is that although most age groups showed a relationship between BMI and physical activity level (e.g. lean boys tended to be more active than obese boys), the real take-home message is that physical activity levels are low in all groups, not just among those who are overweight and obese.  From Dr Sharma (it’s a great post, so please do visit his site to read the whole piece):

…if we convert the rather modest differences in MVPA levels taking into account the increased effort required to move higher body weights, we would find almost no difference in actual calories spent in activities to account for any difference in body weights.Thus, to me at least, these data pretty much blow to pieces the widely held bias that overweight and obesity can be largely explained by lack of activity or that overweight and obese individuals are less physically active (read “lazy”) than “normal” weight individuals.

In light of these data and the tremendous negative emotional and physical impact of weight bias, I stongly believe that discussing inactivity (or exercise) in the context of obesity is not only obfuscating the issues but also a major distraction from addressing the real causes of the problem.

This should in no way imply that the shockingly low activity levels of ALL Canadians (young and old, male and female, slender and obese) should not be cause for alarm given the innumerable health benefits of physical activity and the increasingly recognised health risks associated with sedentariness. In addition, these comments should also in no way imply that increasing physical activity and sensible exercise “prescriptions” are not important prevention or treatment strategies for weight management.

It is, however, hightime to reframe the discussion of inactivity and sedentariness as a discussion about fitness and health risk in general rather than as a discussion on obesity.

Continuing to link the necessary discussion about inactivity to the problem of obesity is not only scientifically unfounded but, by dangerously and unfairly reinforcing stereotypes (not reflected in the actual data), may well do more harm than good when it comes to tackling both the epidemic of obesity and the epidemic of sedentariness.

Now this is not to say that reduced physical activity levels don’t play a role in the obesity epidemic, nor that they are not an important player in weight maintenance.  Again, from Dr Sharma (this time in the comments section):

…absolutely, it is well possible that the overall reduction in physical activity may play some role in the right shift in the bell curve of weight distributions, and getting everyone moving more may eventually lead to a left shift of this distribution (although I am not holding my breath on this one).My issues are not with whether or not activity is important for health or to reduce the risk of obesity.

My issues are solely with the misrepresentation of these findings as reinforcing the stereotype that overweight and obese people are less physically active, when in fact they may well be expending more effort (and calories) than their “normal” weight counterparts.

All of this brings us back to our recent discussion of problematic obesity-related public service announcements.  Because, as you might expect, it’s commonplace for public health messages to make an implicit or explicit link between the inactivity crisis and obesity epidemic. It’s hard not to – obesity is negatively associated with physical activity, and if you’re trying to make a case for why people should be more active, it’s a pretty easy way to get their attention.

Even ParticipACTION, Canada’s standard-bearer for physical activity, has gone down this route on occasion.  For example, their video titled “There is a crisis in Canada” (unfortunately I can’t embed it, but it’s the 4th video down on this page) starts with various shots of headless obese individuals, while the voice-over states “There is a crisis in Canada.  A crisis of epic proportions.  Canadians are simply not moving enoughNearly half of the adults in this country are overweight or obese.” Now those statements are undoubtedly true, but putting them together like that seems to imply that obese individuals are obese simply because they don’t move enough, and that moving more would solve the problem.

Why does this all matter?

In addition to the issue of weight bias discussed by Dr Sharma, I think that it also sets up unrealistic expectations for people about the impact of physical activity.  Yes, if all Canadians were physically active we would likely weigh less as a nation.  But the average weight loss in response to a moderate increase in physical activity levels is very modest, and it’s likely that many people would see no weight reduction of any kind.   Even if it’s in the range of 5% of body weight (which is unlikely over the long-term), it’s probably substantially less than most people are hoping for. In which case the individuals who are only exercising for the sake of losing weight are going to get discouraged pretty quickly (Peter has written a few excellent reviews on this topic with our former supervisor Bob Ross, and I’d recommend this one, titled “Is weight loss the optimal target for obesity-related cardiovascular disease risk reduction?“).  Further, this overwhelming focus on the relationship between inactivity and obesity may lead some lean individuals to conclude that they have no reason to be physically active since their body weight is already in a normal range.

This is a shame because exercise is associated with myriad health benefits, regardless of an individual’s body weight.  In fact, a single session of aerobic exercise results in measurable improvements triglyceride levels, HDL (good) cholesterol, and insulin sensitivity, even though it has no real impact on adiposity.   Further, it has been noted that mortality levels are lower among obese but fit individuals, as compared to lean but unfit individuals, suggesting that we really do need to be promoting physical activity as a healthy behaviour for everyone, not just those who are overweight or obese.

So what strategy should we adopt instead?  I would argue that a good example is ParticipACTION’s new campaign, titled Think Again.  In contrast to the video I discussed above, the “Think Again” ads are funny (and less terrifying) and get the point across that physical activity needs to be an everyday occurrence for all children, without any mention of obesity.  Actually, aside from the “crisis” video, most of their other ads are very good (which I could illustrate if the videos could be embedded on other web sites…), and I especially enjoy the “inactive kids get old before their time” series at the bottom of this page.

As I’ve argued in the past, I think that any public health campaign would do well to focus on the behaviours that we want to promote (e.g. less sitting, more activity), rather than the outcomes that we have less direct control over (e.g. obesity, diabetes, heart disease, etc).  I know that’s not always as media-friendly as obesity, but I think it has a better chance of making a positive long-term impact.

So what do people think – is it time for us to sever the link between the inactivity crisis and the obesity epidemic?

Travis

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32 Responses to Time to sever the link between inactivity crisis and obesity epidemic?

  1. Stephanie says:

    Great post Travis, all I can say is AGREED! I enjoyed reading Arya’s post that followed from the Stats Can data release. We often see PA and obesity linked, well because in epi studies there is a statistical association. I am guilty of this myself with the two endpoints in my study being PA and obesity. However, I am ready to acknowledge that there are effect modifiers that appear between these two factors i.e. clustering of healthy lifestyles, comorbidities, genetic predispositions etc.

    I do remind people when I take their heights and weights, that the two issues are often separate and that PA is really there to help their metabolic profile rather than for weight loss, it can be a good tool for weight maintenance however.

    I think that as you say public health messages need to focus more on behaviours, but perhaps they’re not “sexy” enough or taboo enough to “sell”.

    I’d be interested to see what others think/say…

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    • Rick says:

      Great post Travis. As I mentioned in my response to your previous post (referenced above), I’ve been saying for years that overweight people aren’t just medium sized folks who gave up exercising. As a child I was both overweight and extremely active. So while I don’t doubt that there is a statistical correlation between overwieght and physical inactivity, I’m not convinced that we are interpreting that correlation properly. In fact, it is very likely that many formerly active but overweight people are now inactive simply because their weight makes the physics of maintaining an active lifestyle difficult or painful. In other words, we may very well have the ’cause and effect’ backwards (e.g., the weight problem causing the inactivity). In situations where that’s the case, increasing physical activity certainly is NOT the answer to the weight issue.

      All that said, I remain convinced that public service announcements will be most effective if they simply provide the facts about both the positive impact activity can have on a person’s life and the potential dangers of being sedentary. Goading, coaxing, cajoling, ridiculing, shaming or begging people who are uncomfortable in their own skin to get out there and start exercising is simply not going to have any appreciable impact. So provide the information and let these adults make their own decisions about what to do with it. Remember that those of us who ignore good advice eventually pay the ultimate price for our decisions.

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  2. julie says:

    This is a great idea, I get frustrated that so many (esp. the media) think overweight/obesity = sedentary lifestyles and/or crappy eating. There are people who eat healthy and exercise, yet may eat too much, and PLENTY of people who think they don’t have to exercise or eat healthy, as they are thin. Even when my dog was old and losing weight (dying), people would tell me she didn’t need a walk, she needed food. Um, dogs always like/need walks, and I’m not going to force-feed her.

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  3. I think Gary Taubes’ theory re carbs & insulin isn’t the complete picture, but I suspect he’s spot on when he argues that people aren’t fat because they are inactive, they are inactive because they are fat (more precisely, b/c too much energy is being partitioned to fat storage).

    Re your point about where to put our health behavior energies, I think you’re right to focus on behaviors rather than outcomes, but I also think focusing on diet is far more important than physical activity. Check out Michael Pollan’s comments at the beginning of his recent appearance on Oprah.

    Our terrible industrial diet is not probably just the largest contributor to obesity, it’s the major contributor to cancer, heart disease, and other chronic diseases like diabetes.

    Spurring folks to move more may make for a good PSA, but all it does is shift the onus from what industry is making available to people as foods stuffs and onto the consumer for their supposed failure of personal responsibility.

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    • Travis Saunders, MSc, CEP says:

      I won’t deny the refined foods are bad for you, but it’s not always a zero-sum game. Low levels of physical activity increase the risk for just about every chronic disease, regardless of diet. And for groups that are explicitly focused on exercise and physical activity (e.g. Participaction) as well as physiologists like myself, I there there is a very legitimate reason to be promoting physical activity as an important public health issue. And if we move it away from being focused on obesity, then a lot of the industry-related issues go away as well.

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      • I couldn’t agree more with “there is a very legitimate reason to be promoting physical activity as an important public health issue.” And I also believe that physical activity is important in weight loss as a moderator of fat and basal metabolism … so I think that resistance & interval training are especially valuable. Chronic cardio? Not so much.

        But I think that the *cause* of obesity and chronic disease is far more about a processed/industrial food diet and far less about (lack of) physical activity. Me, I tend to agree with Taubes on this one. People are sedentary b/c they are fat, not the other way around.

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        • Travis Saunders, MSc, CEP says:

          I think that some people absolutely do reduce their physical activity as a result of weight gain. But there are plenty of studies showing that physical activity has an impact on insulin sensitivity, blood lipids, cancer risk, etc, independent of diet. Granted, I don’t think that there’s really enough evidence to prove that it’s driven more by diet or exercise.

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          • I think one problem is that many (most?) people approach exercise to address calories in vs out which doesn’t seem to work as well (e.g., lots of cardio typically increases appetite). Incorporating exercise to improve insulin sensitivity makes tons o’ sense to me!

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            • Travis Saunders, MSc, CEP says:

              As usual I think we mostly agree, I just wanted to take this opportunity to link to a paper that I really like:

              http://www.portalsaudebrasil.com/artigospsb/obes051.pdf

              It’s by John Blundell, who is probably *the* guy when it comes to the relationship between diet and appetite. His findings consistently show that there isn’t much of an increase in appetite early in an exercise program, and that even later in a program it only compensates for about 30% of the energy expended during exercise. So it makes a difference, but it’s not as big as most people think.

              Now whether people think “I exercised, so I can eat more” (e.g. eating more but not necessarily because their appetite has changed at all), that’s a completely different story.

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  4. Brian says:

    Great post. It’s nice to see articles like this and others stating that it’s a little more complex than eating less and exercising more. In all of my years of doing this (20+ now, which I begrudgingly admit), I have yet to meet an overweight or obese person that wanted to stay that way. Those saying it’s all about willpower really show they have no clue what they are talking about (it’s not easy, but it’s not ALL willpower).

    @Beth…I agree with you regarding Taubes and his point on obesity and partitioning. I don’t think it’s a carbohydrate problem per se, but we (Americans, at least) consume too large a volume of the bad ones, which gets to your second point: an industrial diet.

    I don’t lay all of the blame on food manufacturers, although they take some. They need to make a buck. The ultimate blame lies at the food guide pyramid and USDA – promoting diets based on 60% carbohydrate with too much emphasis on whole grains and added sugars, too little emphasis on vegetables, healthy fats and protein.

    Brian

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  5. JeninCanada says:

    It is so nice to hear people talking about obesity and activity and what we can do to be healthy (and not lose weight), instead of the usual garbage dump of “But if fat people just put the doughnut down/got off the couch/etc they could be so THIN and HEALTHY!!!”

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  6. Paul Murphy says:

    http://obesitythunderbay.ning.com/video/do-you-drink-93-sugar-packets

    Just one question . Who funds the Particapaction Activity Model ?
    Is food our next tobacco?

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    • Travis Saunders, MSc, CEP says:

      I don’t the Big Food conspiracy totally checks out in this case (and I’m not really sure how the video relates to things…).

      I’m not sure of all the details, but in the past Participaction was largely (and possibly exclusively) government funded. I know that it was put on the shelf in the early 2000′s when funding was cut, and brought back a few years later when funding gov’t funds were increased. They do have their business partnership with Coke, but they also have partnerships with sporting goods companies (e.g. Sport Chek), and I haven’t seen any change in their mission or their messaging (e.g. be more physically active) since those partnerships began.

      I’m pretty sure that their one and only mandate is to increase the physical activity of Canadians, and that the bulk of their funding is form the taxpayers.

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  7. S. says:

    Do you exercise? Because I can’t imagine anyone who does going to such lengths to discredit something that is indeed a part of a culture of health. if you exercise consistently, and regularly, even gently, it becomes very pleasurable sooner or later. So no-one exercises “just for weight loss”. We are animals. We were built to move. Our bodies like it.

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    • Travis Saunders, MSc, CEP says:

      Just for clarification, was this in response to the post, or one of the earlier comments?

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  8. S. says:

    (…) “sever the link between inactivity and obesity” will be grabbed onto by many low-carb proponents as a reason not to even take a walk, let alone exercise. Headlines like this make me cringe.

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    • Travis Saunders, MSc, CEP says:

      @ S,

      I’m not sure I understand where you’re coming from. What part of the post discredited exercise? I do know people who have begun exercising explicitly for weight loss, and have stopped exercising when the weight loss wasn’t as rapid or as dramatic as they had hoped, or simply because they didn’t enjoy it. And that is very unfortunate because they are now missing out on all the other exercise-related health benefits.

      My argument is that people *should* exercise, we just shouldn’t be telling them to do it for weight loss since it probably won’t result in the amount of weight loss that they are hoping for (it may for some, but not for the majority).

      How do low-card diets relate to this?

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  9. S. says:

    The headline! The part that will stay with people. I can guarantee this is being repeated in low-carb forums across the web. Something like “there’s a study that debunks it. We don’t need to exercise. “

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    • Travis Saunders, MSc, CEP says:

      Is there anything untrue about the headline and/or do you have a suggestion for another headline that conveys the message of the post that wouldn’t cause this problem?

      And why are these low-carb folks looking for an excuse to stop exercising?

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  10. S. says:

    I’m not a low-carber, by definition. (Can it count if I’ve just given up Sachertorte for a few months?) I can’t figure out why, or should I say, I’ve tried to reason with some, but to no avail, because they are stuck in the euphoria phase of weight-loss. We’re losing weight! It wasn’t our fault after all! Pass the steak! No wait, butter it first!

    I can’t rewrite your headline. It would probably come out all sun-journalisty.

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  11. Nice, thoughtful post as usual, Travis. I understand your arguments, and they’re reasonable — but I thought your comment on Dr. Sharma’s blog raised an important point. If, as the new Statscan data suggests, EVERYBODY is sedentary, then how can this fact argue that exercise does or doesn’t combat obesity? We can’t say exercise doesn’t work if no one is exercising!

    Dr. Sharma’s main point seems to be saying: Look, obese and normal-weight people both have similar levels of physical activity, so it’s not fair to shame obese people for being lazy. This is, of course, both true and important.

    But imagine a hypothetical world where, under “normal” evolutionary circumstances people get 2-5 hours of exercise a day and are generally lean. And imagine that, if they all stop exercising suddenly, about half of them have the genetic predisposition to become obese, while the other half are seemingly unaffected (though they may suffer “invisible” metabolic consequences). Just like in our world, it would unfair to demonize the obese people for laziness, since they’re not doing anything different from their slender peers. BUT it doesn’t follow that the obesity epidemic in this hypothetical world is unrelated to the inactivity crisis.

    [DISCLAIMER: I understand that the world is more complicated than the hypothetical example in the previous paragraph.]

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    • Travis Saunders, MSc, CEP says:

      But imagine a hypothetical world where, under “normal” evolutionary circumstances people get 2-5 hours of exercise a day and are generally lean. And imagine that, if they all stop exercising suddenly, about half of them have the genetic predisposition to become obese, while the other half are seemingly unaffected (though they may suffer “invisible” metabolic consequences). Just like in our world, it would unfair to demonize the obese people for laziness, since they’re not doing anything different from their slender peers. BUT it doesn’t follow that the obesity epidemic in this hypothetical world is unrelated to the inactivity crisis.

      Excellent question, Alex. I actually tend to think that the hypothetical world you describe is probably pretty close to the situation we now find ourselves in. Although it’s a matter of debate, I think there is good evidence that physical activity levels are lower than they were in the past, and that this plays an important role in the etiology of the obesity epidemic (although it’s pretty much impossible to prove on both counts). And so in that sense it is very possible that the inactivity crisis and the obesity epidemic are linked.

      But with respect to the public health message, I think it’s best to try to shift the focus away from body weight. If every Canadian were suddenly meet the physical activity guidelines, I have no doubt that *some* would lose weight, while a great number more would probably stop gaining weight, or at least gain weight more slowly (In general it is easier to prevent weight gain than to reverse it, and exercise is no exception). But a far greater number still would experience a reduced risk of mortality, improved insulin sensitivity, reduction in lipid levels, lower waist circumference, etc. And seeing as people often do get frustrated when exercise fails to deliver the type of weight loss that they are hoping for, it seems best to shift the focus to the benefits that exercise can deliver more consistently. If the goal is to encourage people to increase their level of physical activity over the long-term, then I think it makes sense to focus on the benefits that people are most likely to experience, rather than a benefit that relatively few will experience. And the issues associated with weight bias and discrimination provide yet another reason to shift the focus to the other benefits of increasing PA.

      I think that the new Canadian PA guidelines are a good example of how this can be done, without necessarily throwing out the mention of body weight altogether. The one page summary for each age-group lists several health benefits associated with exercise, with “maintaining a healthy body weight” relatively low on the list, and the older adult page is the only one that mentions that body weight may “improve” with increased exercise.

      I had planned to include more on this in the original post but it just got too long and unwieldy so I cut it out. Thanks for giving me the opportunity to bring it up :) I’m curious – do you think this position (that PA plays a role in weight, but it shouldn’t be the focus of our public health campaigns) is a tenable one?

      Travis

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      • Travis — thanks for the thoughtful reply. Sure, I think that position is tenable, and I generally agree with it myself.

        But I do think it’s worth bearing in mind the distinction between crafting effective public health messages and understanding how the human body works. My sense is that Dr. Sharma and many others (not you!) sometimes conflate the two — so that, for example, he believes that “these data pretty much blow to pieces the widely held bias that overweight and obesity can be largely explained by lack of activity.” As we discussed above, I don’t think these data say anything either way about the relationship between obesity and PA.

        To distinguish between the two, we might ask how public health recommendations would change if incontrovertible proof emerged that two hours of reasonably vigorous daily exercise would universally eliminate obesity and add 10 years to lifespan. My sense is that PA guidelines wouldn’t really change, because they’re formulated based on what people currently do, and how much they can “realistically” be expected to increase.

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        • Travis Saunders, MSc, CEP says:

          Thanks for responding, always interesting to hear your views!

          To distinguish between the two, we might ask how public health recommendations would change if incontrovertible proof emerged that two hours of reasonably vigorous daily exercise would universally eliminate obesity and add 10 years to lifespan. My sense is that PA guidelines wouldn’t really change, because they’re formulated based on what people currently do, and how much they can “realistically” be expected to increase

          I think that’s a general misconception about the PA guidelines. To my understanding (and based on everything I’ve heard from those involved in the process, and the info provided on the CSEP website), the guidelines are based on the amount of physical activity that is associated with meaningful health benefits. So it wouldn’t really matter if a study showed conclusive proof that exorbitant amounts of exercise prevented/cured any particular disease, since meaningful health benefits are still clearly seen at the current guidelines. It’s a benefit of the new guidelines that they happen to be more realistic for most people, but that’s not the reason why they’ve been set at current levels.

          You’re right that I am (slightly) more “pro exercise” when it comes to weight loss than some of our colleagues like Dr Sharma and Yoni Freedhoff, and I agree that he was reaching a bit at times (which is why I asked the questions for clarification on Arya’s original blog post). But that particular post aside, the evidence can make a convincing case either way, and there is a fair amount of academic debate over this (to the point that I think it’s become a bit of a needless distraction).

          I would say that 90% of obesity/physical activity researchers agree that exercise has a role in weight loss but that for the average person, exercise as a stand-alone treatment is not going to result in dramatic weight loss (I’ve heard several people argue that it plays a role, but that its much smaller than people typically expect, which is a point I agree with). Similarly, I think most would agree that it plays a larger role in weight maintenance or the prevention of body weight than it does in weight loss.

          But we really are quibbling over the details more than anything else. Which is why I get a bit chuffed whenever I see a headline that says either “Exercise is useless for obesity” or “Exercise your way to weight loss”, because there’s plenty of evidence suggesting that both of those absolute extremes are untenable.

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          • I think we need the series on exercise the way Kurt Harris is doing on macronutrients. Referring to “exercise” generally seems to me to be the biggest reason for the absolute extremes Travis mentions.

            I think chronic cardio a la the Biggest Loser here in the states is not desirable as a public health perspective re weight loss. Will it work? Yes, but so did the Twinkie diet in the short term. Watching the newer shows here (like Heavy and I Used to be Fat) where trainers practically torture their fat clients into losing weight through excessive (IMO) exercise makes me want to never step foot in a gym.

            I expect that the mainstream will come around eventually to the idea that specific exercise (such as HIIT) is absolutely useful in terms of weight loss, but that this will have very little to do with calorie balance and a lot to do with energy metabolism and insulin sensitivity etc. Better still, it will be something far more manageable for the average person to do and thus a lot more likely to be effective.

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  12. Norm Trowell says:

    I think exercise can be looked at as a tool in weight maintenance once one’s
    “healthy” weight has been attained; plus it does give you those extra spare calories each week to have that piece of pie or ice cream.
    Exercise has to be enjoyed for its own right.

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  13. Ash Routen says:

    Interesting post Travis, I certainly agree that the primary target should be to increase/maintain (and stop the adolescent decline) physical activity behaviours in children, on the premise that it is a precursor to adult activity, and that an improved metabolic profile is probably more important than weight status? (fat fit debate etc)…Do the new Canadian guidelines have a sedentary recommendation? It seems there is often a discrepancy between optimal doses of PA for health and the feasibility or likelihood of kids actually adhering to that amount, hence I like the Janseen & Le Blanc (2010) statement that “some of the health benefits can be achieved through a average of 30 mins per day”. I agree that the focus should be on the dose of activity that is beneficial to the widest number of health outcomes.

    I saw above that someone mentioned the possibility of reverse causality in the association between PA and obesity, some interesting findings on this which I’m sure you’ve probably seen anyways: http://adc.bmj.com/content/early/2010/06/23/adc.2009.175927.abstract
    The levels of MVPA reported for Kids do seem rather low! In the paper they have used 1 min epoch’s I think on there accel data, which might have underestimated the levels of MVPA. Also the use of MVPA as a composite variable may be clouding the issue, as you know most studies have shown that only VPA is associated with adiposty/bmi in kids. While it seems that normal weight kids had a mean VPA of 2 mins vs. 1 mins in overweight kids, maybe this was underestimated due to the epoch used? and the gap may actually be greater. In addition normal weight kids were found to do ~20 mins more of MPA than Obese kids, clearly some difference there which might be contributing?

    Finally not sure I agree with Dr Sharma on the accel data needing correction for body weight. Accelerometer counts are calibrated (regressed) against a measure of EE normally and then cut-points derived from this relationship. Providing the sample in the calibration study is similar to the studied sample then cut-points would be pretty accurate in terms of relative intensity, as that’s the purpose of them as opposed to predicting EE which is has quite a bit of error on an individual level.

    Only just started reading this blog in the last few weeks, it’s great, top effort!

    Cheers,
    Ash
    Worcester, UK.

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    • Travis says:

      Lots of excellent points, Ash!

      Canada’s new PA guidelines did *not* include any recommendations for sedentary behaviour. Instead, the Canadian Society for Exercise Physiology will be releasing sedentary guidelines for children and youth on Feb 15, which are meant to complement the PA guidelines. As far as I know, these will be the first evidence-based sedentary guidelines anywhere in the world, so that’s going to be a pretty good step in recognizing the importance of sedentary behaviour as its own construct, as opposed to simply being the lack of PA.

      When you say that most studies have shown that only VPA is associated with BMI in kids, are you referring to self-report or accelerometer studies? I can believe that for self-report studies, but would be a bit more surprised with accel data (although not totally surprised). Reverse causality is definitely a factor, but PA and sedentary behaviours are also very homogeneous these days, so I think that makes it difficult to see relationships in epidemiological studies even where physiologically we might expect there to be one.

      Personally I’m not a fan of using accelerometers to calculate EE. There are too many black box calculations in there that we have no way of getting at so I think it’s best to stick with what accelerometers actually measure – movement. They do create movement cut-points based on EE, but in my understanding the cut-points are pretty contentious and most of the studies that have validated the cut-points have been pretty small. All that to say that I probably wouldn’t bet the farm on EE estimates based on activity counts one way or another :)

      Thanks again for the great comments, hope to have more discussion with you in the future!

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  14. Ash Routen says:

    * When I referred to ‘the paper’ above I meant the Colley (2011) one, not the one I linked in!

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  17. All properly written.
    But I can not imagine any other lifestyle.
    This is sedentary work, and nowhere on it does not go away.

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