The latest findings on sedentary behaviour and mortality

Today’s post is a summary of a fascinating new paper published in Annals of Internal Medicine on the relationship between sedentary behaviour and premature mortality (available here).  The paper has garnered a tremendous amount of media attention (see here, here and on Jimmy Kimmel here), and we are fortunate to have a summary of the paper written by lead author Avi Biswas.  You can find more on Avi at the bottom of this post.  This post is also available at the Sedentary Behaviour Research Network.


In a similar vein to other reviews that have examined the association between sedentary time and various health outcomes, our study sought to not only update the sedentary behavior literature but also focus exclusively on studies that adjusted for physical activity in order to assess the independent effects of sedentary time. This differentiated our meta-analysis from two others which had previously reported independent risks (Wilmot et al., 2012 and Schmid and Leitzmann, 2014), as investigating the independent effects of sedentary time (by reporting the effects from studies that at least adjusted for physical activity) was our core focus rather than among a limited subgroup of available studies. Additionally, our study examined the extent to which levels of physical activity may potentially modify the associations between sedentary time and outcomes, which to the best of our knowledge has not been systematically quantified in other reviews.

What we did

We devised a comprehensive, systematic search strategy of studies that assessed sedentary behavior in adults as a predictor variable and correlated to at least one health outcome. We also focused on direct clinical outcomes (death, disease incidence and health service use) rather than indirect surrogate outcomes such as quality of life, insulin sensitivity and weight gain) as we believed the later type would present inconsistent end points and cutoffs. We then collected the statistical effects associated with the longest reported sedentary time (vs. a baseline of the lowest sedentary time) and that adjusted for physical activity. These were used to pool the analysis of the overall effect for each outcome.

When examining whether physical activity modifies the effects associated with sedentary time, we reanalyzed all available studies that met our selection criteria to see if they reported statistical effects of the longest period of sedentary time with the highest duration and intensity of physical activity.

What we found

Our study found that long periods of sedentary time was positively associated with an increased risk for dying (from all-causes, cancer and cardiovascular diseases) and increasing the risk for certain forms of cancer (specifically breast, colon, colorectal, endometrial, and epithelial ovarian cancer), cardiovascular disease and type 2 diabetes. Our meta-analysis found that the largest association was with type 2 diabetes (91% increased risk).

Of the limited studies that reported the joint effects of physical activity and sedentary time (only quantified for dying from all-causes), our pooled analysis found that the risk of dying from all-causes due to long sedentary time was 30% greater in those who spent little to no time in regular physical activity than those who at least met their physical activity recommendations of 30 minutes/day. While the pooled effect corresponding to high levels of physical activity and long sedentary time were found not to be statistically significant, we believe the consistent and strong effects associated across all-cause mortality-assessed studies (and to a lesser degree, cardiovascular disease and mortality) suggests that there is a strong likelihood that physical activity alone does not completely reduce the negative effects from long sitting time. We believe more work needs to be done to tease out whether there is such an association.

Take home message

Our study provides the strongest evidence as so far, to suggest that long periods of sitting is associated with various health outcomes. Furthermore, while regular or high levels of physical activity seems to have protective effects on reducing sedentary time-associated risks, we believe there is sufficient evidence to suggest that a focus on promoting regular exercise AND reducing sitting time to be a better public health message.


“Sedentary Time and Its Association with Risk for Disease Incidence, Mortality, and Hospitalization in Adults” paper, Published in the Annals of Internal Medicine (2015: 162:123-132)/.

About the Authors

Aviroop (Avi) Biswas

Aviroop (Avi) Biswas

Avi is a PhD candidate at the Institute of Health Policy, Management and Evaluation, University of Toronto and the Toronto Rehabilitation Institute. Along with this meta-analysis study, his PhD work is focused on understanding the risks of sedentary behaviour among exercise-engaged cardiac rehabilitation patients, in lieu of developing non-sedentary interventions.






Dr. David Alter

Dr. David Alter

Dr. Alter is a Senior Scientist at the Institute of Clinical Evaluative Sciences and research director of the Toronto Rehabilitation Institute’s Cardiovascular Prevention and Rehabilitation program. Dr. Alter’s research spans across many disciplines including cardiovascular health services and outcomes, clinical epidemiology and social determinants, cardiac rehabilitation and more recently, music and medicine. He has published over 125 scholarly peer reviewed papers in prestigious journals such as the New England Journal of Medicine and the Journal of the American Medical Association. Dr. Alter has also received funding from various agencies including the Heart and Stroke Foundation of Ontario.


Category: News, Peer Reviewed Research, Sedentary Behaviour | Tagged | 3 Comments

Standing desks in the classroom

standing desks

Today’s post is an interview with teacher Adam Aldred, a teacher who has incorporated standing workstations into his classroom.  You can find more on Adam below.  Detailed instructions on how he built his standing desks can be found here.

Who are you?

I am a grade 10-12 teacher, in a program called Options and Opportunities (O2) in a small town in rural Nova Scotia. This program is specifically designed to give kids a more experiential, hands-on approach to learning and expose them to a wide variety of post-secondary options, and other learning experiences like service-learning, co-operative education, volunteerism, etc.

I absolutely love the material, which covers everything from citizenship to job interview skills, workplace safety to changing flat tires, I love the way it shapes the kids’, and I love how close our little family becomes over the three years they are with me. On any given day you walk into my classroom you are just as likely to see impact guns or measuring spoons in my kids’ hands as you are to see pencils, and I love the pace and the constant state of change. We have a fantastic curriculum, as well as a healthy budget to support our classes, and these pieces offer a lot of flexibility in how I can teach and reinforce concepts.


What started this movement in your classroom to combat sedentary behaviour?

After stumbling onto some initial research on ‘Sitting Disease’, I texted my friend Kerry Copeland who is a youth activity coordinator for Doctor’s Nova Scotia to see if she had heard of it before. She had and directed me to some more research which I happily consumed, and which also left me feeling quite uneasy. Personally, I am a very active individual, but I knew that the same can’t be said for many of my students, and I was quickly learning that even for those who are active too much sitting time can offset any benefits that came from their movement.


At what point did you talk to your students about what you had read?

I thought about it for the weekend, and then on Monday I took the research to my grade 10s. And we talked, hypothesized, and complained about a six-hour school day that almost mandates that the kids ‘sit down and listen up’. One of the big things in our class is that complaining isn’t allowed to be the end of any discussion; you have to own it and try to take steps in the right direction. I asked the students if they would be interested in building and trying out some standing workstations.


How did the students respond to the offer?

They jumped at the opportunity!

That day just happened to be a double period so while they went to lunch I sketched out a basic plan (what I call our alpha model). Our classroom already had OSB tabletops which we had built to snap down over top of three desks to protect them from things like errant screws or hammer swings. I incorporated those tabletops into our alpha design, and when they returned from lunch we dug the 2x4s out of the shed, got out the tools and went to work. By the end of class we had three different-sized, fairly-unsteady models that we would test for the next few weeks.


Did the initial design, the alpha model, stay roughly the same for those few weeks?

Not at all: as we used them we talked about the pros and cons. Over those passing weeks we would take them all apart periodically to modify dimensions in an effort to get an ideal model.  [A detailed description of Adam’s standing desks can be found here]


What did you decide for the form of the beta model?

What we came up with in the end was to build a platform underneath one part of the desk so that our shorter students could access the desktop at a height that was more suitable for them. In addition to this, we had learned that while the standing desks were great for listening, reading, and writing, they were far too tall to be used as workbenches, which is an integral part of our class. So in the design of the beta model, the OSB tabletops were left unattached so that they could be easily removed and snapped down over desks, which gives the optimal height for such tasks as sawing, routering, etc.


How much of your classroom desk space is dedicated to the standing work stations?

We have three of the standing workstations, each accommodating three or four students, and we still have seating for 12 people in the room so they have the option to sit if they choose. Many of them say they prefer the standing desk, and I think the majority enjoy that they have the option.


Any further plans with different models?

Our next task will be an attempt to make a variable-height workstation for me at the front of the class; we are just waiting for the special hinges to arrive. Looking ahead, I will also try to come up with some concrete models of two student desk-concepts that include a) a multi-tiered desk that each student could decide how to use depending on the day, and b) a standing setup with a rail to lean back against, allowing the student a number of ways to support their weight all while standing.


How long ago was it that you first began the standing desk project?

We started the standing desk project in November. The beta models have been in use for over two month now.


Have you had any interest or concern from other teachers?  Are any thinking of following your lead?

I kind of do my own thing down at the end of a wing of the school that is, right now, only occupied by my classes. This tends to limit the number of other teachers that see my room as there aren’t many random passers-by. From what I can gather the few that have been in seem to think the desks are interesting and a good idea, but I can’t gauge whether they think it is a passing trend/novelty or is actually something that will stick around long-term.


Are there any specific tasks that you’ve found work particularly well when standing? 

I find my kids tend to be more open to volunteering help when standing. I am not sure if this is strictly because they’re already up, or that the act of getting out of a chair is labour-intensive, but it seems that when I ask for someone to help out it is almost always a standing student. The standing desks are great for reading/writing/engaging in classroom discussion. They also seem to make the students more likely to engage with their peers in positive social behaviour, and I have wondered if this is because the act of standing naturally positions one’s body in a manner that appears more open and willing to engage. This, however, might be an instance of confounded variables, as those who choose to stand may be a more open, inviting part of the population, or other reasons.


Do you find there to be any tasks that really don’t work well when students are sitting in your classroom?

In regards to seated desks, I find them to really hinder active engagement, both physically and mentally.  In the traditional-desked classroom I would often have my students stand up to complete simple 10-second tasks (a dance, a spin, a vocal call back, etc) to get the blood flowing again. It wasn’t until reading the research on sedentary behaviour that I came to fully understanding why this was happening to my students.


It sounds like you are in a somewhat unique teaching environment.  Do you think that these solutions would work in a more traditional classroom setting?

I do, but I think the teachers and their students would need to figure out what works in their particular reality.


Have you found the desks to have any impact (positive or negative) on classroom management? 

None, whatsoever.


Do you have any thoughts or responses for teachers that might be concerned about going down this road? 

I would just say that if your kids are old enough to talk about the research on sedentary behaviour to just throw it out there and see what they think. If the kids are as affected as mine were, they will have all sorts of thoughts and ideas. Also, if you have any questions, or if I can be of help to you please don’t hesitate to email me at


Do you have anything else you would like to add?

Only that I have fantastic administrators who are very diligent in their attempt to meet our public school mandate of providing a healthier school culture/environment for our students. I would encourage any other educators that are interested in standing workstations for their classroom to get their administration on board as early as possible as they often have a perspective that important and necessary.


Thank you, Adam

My pleasure, thank you for having me, Travis.

Category: News | 2 Comments

New obesity medication now available in Canada

saxendaThe very first Obesity Panacea post was written back in November 2008. The topic of that post was the removal from the European market of an obesity medication that had been previously heralded as a potential panacea (but was never approved in US or Canada). That drug was rimonabant (Acomplia), an appetite suppressant that works by blocking the CB-1 receptors of the endocannabinoid system – the same system which induces the “munchies” in response to smoking cannabis. Rimonabant not only suppressed appetite, but was associated with anxiety and depressive mood disorders – the same side-effects which initially prompted the US FDA to refuse approval of rimonabant back in 2007.

Two years later, another appetite-suppressing medication, sibutramine (Accomplia) was also withdrawn from the Canadian and US market due to increased risk of cardiovascular events and strokes.

Thus, over the past five years there was only a single obesity medication available to obese patients in Canada – orlistat (Xenical®). This agent reduces the absorption of ingested fat by about 30%. The 30% that doesn’t get absorbed ends up in the stool, which, as you’d expect, can result in some rather challenging gastrointestinal side effects (e.g. oily discharge).

All of that changed yesterday (Feb. 26), when Health Canada approved a new obesity medication. This new medication, liraglutide 3.0mg (Saxenda®), which is administered via a daily subcutaneous injection has actually been available in Canada but at a lower dose and marketed under a different name (up to 1.8mg, Victoza®) for the treatment of type-2 diabetes. Saxenda is approved for weight loss in addition to diet and exercise for patients with a BMI ≥30kg/m2 or a BMI≥27kg/m2 plus at least one weight-related illness (i.e. hypertension, dyslipidemia, or diabetes). This drug has been studied in a number of large clinical trials which suggest that patients experience an average reduction of 6.3-8.0 kg over and above that achieved with placebo (fake injection) at 1 year of therapy. This of course isn’t the most exciting magnitude of weight reduction, but keep in mind that most experts recommend that obese individuals only aim at 5-10% weight loss to reap health benefits.

More importantly, as we’ve highlighted ad nauseam, positive health behaviours – including a healthy diet and increase physical activity have a tremendous impact on your health regardless of your weight status. And these behaviours form the basis of ANY obesity therapy.

Nevertheless, obese Canadians who only had one option for a medication to help them lose weight (and have oily flatulence), now have another option.

Of course, obese folks in the US have many more pharmacological options – including two combination therapies (Qsymia® and Contrave®) – that remain unavailable in Canada or Europe.


Category: News | 2 Comments

The Fatter we Get, the Less We Seem to Notice

obesity ratesA significant number of overweight and obese individuals believe their body weight to be appropriate or normal and are satisfied with their body size. Misperception of overweight status is most common among the poor vs wealthy, African Americans vs white Americans, and men vs women. The unfortunate consequence is that overweight individuals who perceive themselves to be of normal weight are less likely to want to lose weight in contrast to overweight individuals with accurate perceptions. Such individuals are also more likely to smoke, have a poor diet, and be physically inactive.

An interesting hypothesis tested by Burke and colleagues in an Obesity journal article is that misperception of overweight status can actually increase over time in response to the secular increase in the average BMI of the US population. In other words, due to a possible anchoring effect, the more overweight the people around you become, the more one’s sense of “normal” weight is raised upwards, and thus the less likely you are to consider yourself overweight, even though you actually may be. Indeed, given that most individuals you interact with on a regular basis are likely to be overweight or obese, it becomes tough to define what someone with a normal weight looks like.

To answer the question at hand, the authors compared two representative cohorts of the United States population (NHANES) – one surveyed in the early 90’s and the other surveyed in the early 2000’s. Stated simply, they divided each cohort by gender and weight status (BMI) and compared the general perceptions of the individual’s weight.

What did they find?

Just as the researchers predicted, overweight individuals today are less likely to classify themselves as “overweight” in contrast to overweight individuals surveyed over a decade ago. For example, the proportion of overweight women who perceive their weight o be “about right” increased from 14% to 21%, and that among overweight men from 41 to 46%. This latter point also well illustrates the gender bias of weight misclassification.

Interestingly it was among individuals aged 20-25 that the greatest shift towards inaccurate weight classification occurred – overweight individuals in this age group were most likely to see themselves as “normal” weight.

Additionally, independent of the effect of time, this study confirmed a number of factors influencing one’s ability to accurately gauge their own weight status: those who are educated are more likely to self-classify as overweight than those who are not, those with higher incomes are more likely to feel overweight than those with the lowest incomes, married people are more likely to feel overweight than never-married people, and members of minority groups are less likely than whites to consider themselves overweight.

So there you have it – as a population, we are all getting fatter. Making matters worse, the fatter we all get, the less we seem to notice and the less likely we are to do anything about our bulging waistlines.


Burke, Heiland, Nadler. From “overweight” to “about right”: evidence of a generational shift in body weight norms. Obesity. 2010;18(6):1226-34.

Category: News | 1 Comment

Grade 1 class using standing desks

Very cool story out of Saskatchewan this week, with a grade 1 classroom that has converted to standing desks.  Unfortunately I can’t embed the full interview, although it can be seen here. A short video from CBC is included below, which shows children using the desks.

Some highlights from the CTV article:

In September, Justin Sauer raised the height of all the desks in his classroom at Delisle Elementary School, in Delisle, Sask.

He was motivated by research that shows sitting too much can lead to health problems in adults and children.


Since propping up all of the desks using metal extensions, most of Sauer’s students are opting to stand.

He’s already noticed some changes.

“(Parents) told me their kids were sleeping better, had better postures,” he says.

On top of that, several appear to be paying more attention in class.

“I can say definitively that five or six kids have really benefited,” he says.

Sauer hopes that his students aren’t the only ones who learn this lesson. He thinks fellow teachers should take note too.

They do note in the video that kids don’t have to stand – they have the option to sit or stand (as we all should).  In the coming weeks I’ll have a Q&A with teacher Adam Aldred, who has converted his high school classroom to standing workstations as well.

Hat tip to my wife Daun and our friend Heather for telling me about the story.


Category: Sedentary Behaviour | 1 Comment

Participants Needed For Online Survey on Weight Stigma

Norah MacMillan at York University is doing a research project on the topic “Social Media Use on Weight Stigma and Eating Attitudes”.

She is looking for participants between the ages of 18-40 years to complete the survey.

It is a short survey (~78 questions) and should take about 10-15 minutes to complete.

If you are in that age group, please consider checking out her survey.  And if you have a study of your own that is in need of participants, feel free to let me know.



Category: News | 2 Comments