Morning workout vs breaks from sitting – which is better for blood sugar?

Today’s guest post comes from Dr Meredith Peddie. You can find more on Meredith at the bottom of the post.

“Sitting is the new Smoking”… we’ve all heard it…. It even made an appearance on Criminal Minds last week (sorry New Zealand TV is probably months out of date)… and yes, there is an ever growing number of studies that indicate that people who sit for long periods are at greater risk of developing, and dying from cardiovascular disease, diabetes and cancer.  There are also studies that indicate that people’s pattern of sitting might also affect their risk of diabetes and cardiovascular disease (longer periods of interrupted sitting are worse than short bouts that are regularly interrupted with activity).  However, the vast majority of these studies are observational in nature, meaning that they can’t tell us if changing peoples sitting patterns will actually reduce their risk of developing and dying from the above mentioned diseases.

Unfortunately, a study in which you actually changed peoples sitting patterns and then waited to see if that affected whether or not they would develop cancer or cardiovascular disease would take years, and require a large number of people…. So that is where our study comes in… we decided to investigate whether different patterns of activity and sitting would affect risk factors for cardiovascular disease in a very acute setting.  Specifically, our study was designed to compare the effects of prolonged uninterrupted sitting, a single continuous bout of physical activity combined with prolonged sitting, and sitting with regular activity breaks on postprandial metabolism.  

To do this we conducted a randomized cross over study in which 70 healthy, normal weight men and women participated in three intervention days, one in which they sat continuously for 9 h (except then they had to get up to use the bathroom), one in which they walked briskly uphill on the treadmill for 30 min and then sat for the remainder of the 9 h, and one in which they performed regular activity breaks (1 min and 40 sec walks on the treadmill every half an hour – giving us a total of 30 min on the treadmill over the 9 h) sitting in between each break.

During this time we fed them three times, and collected blood samples at regular intervals for the analysis if glucose, insulin and triglyceride.  – Sound familiar? Yes, our study is very similar in design to a study Travis conducted as part of his PhD, and to the study David Dunstan conducted in Australia, however, the key differences are we used healthy, normal weight adults as participants (not children or overweight adults) and had an intervention day which was designed to mimic someone meeting the current physical activity guidelines, but still spending a lot of time sitting.

What did we find?


Peddie et al., 2013 (Source). Click to enlarge.

Regular activity breaks resulted in a 39% reduction in plasma glucose, and a 26% reduction in plasma insulin when compared to prolonged sitting.  But what was surprising was that we also found a 37% reduction in plasma glucose and an 18% reduction in plasma insulin when regular activity breaks were compared to 30 min of physical activity combined with prolonged sitting. 
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Category: Guest Post, News, Sedentary Behaviour | Tagged | 11 Comments

Watching this interview may be bad for your health

A couple weeks ago I had the pleasure of being interviewed on the local Global TV morning show here in Halifax, talking about the health impact of sedentary behaviour.  It was a fun interview, and we covered a lot of the main reasons why sedentary behaviour is bad for your health. And no, the irony of going on TV to talk about the health impact of TV was not lost on me (sitting is bad for you; sitting in front of a TV is very bad for you).  In particular, the McDonald’s product placement proved my point about the ubiquity of food ads on TV.  I think it went well (Peter told me that I no longer look like a grad student – so mission accomplished!), so I thought I’d post it up here.  Enjoy!


Category: Interview, News | 4 Comments

You’ll need running shoes to see this theatre production

SleepNoMoreTravis and I have been blathering on over the years about the downsides of prolonged sitting. We may have even made a few of you as paranoid as we’ve become about keeping sedentary time down to a minimum. We’ve told you to drink plenty of water while at work so that you are forced to get up and go to the bathroom. We’ve suggested you have walking meetings, have a standing or treadmill desk, or at least a peddler under your desk to keep your feet moving. Hopefully, none of you have lost your jobs on account of our advice. We’ve even discussed the merits of stepping in place during commercial breaks if you happen to be spending your evening glued to the television.

But in some instances, prolonged sitting is just out of our control. On long-haul flights, for example, despite my best efforts to get up as often as I can and walk the isles, I still spent plenty of hours with my behind firmly planted in my seat. Those darn “fasten seat belt” lights seem to come on at the slightest whisper of turbulence, and depending on your seating arrangement, the passengers seated beside you might grow aggravated with your frequent request to get past them to “stretch your legs”.

I also believed enduring prolonged periods of sitting would apply when attending a theatre production. That is, until I attended Sleep No More in New York City. You see, in this show, which is loosely based on Shakespeare’s MacBeth, there is no stage on which the 20 or so actors perform and there are no seats in which the audience sits. Instead, actors and audience members interact with one another throughout 5 floors of a fictional 1940s hotel named the McKittrick. Multiple scenes occur concurrently throughout the vast space, and audience members are free to move around and do whatever they please.

But sitting, the audience does very little of. In fact, most of the time you are walking around the hotel, poking in and out of various rooms, playing with anything you want (books, piano, random clothes, rotary phones, etc.) And at other times, you are sprinting trying to follow the ensuing action.
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Category: Physical Activity, Sedentary Behaviour | 3 Comments

Help stop fat bullying

Today’s guest post comes from author Linnie von Rekowsky.

Imagine being spat at while hearing choruses of peers chanting ‘porky’, ‘puffy’ or ‘fatso’. Imagine being pushed, tripped and otherwise physically assaulted. For many overweight children (and adults) public humiliation is a painful, daily reality.

“Weight stigma can affect every aspect of a child’s life. Children who are bullied for their weight may want to skip school, avoid physical activity and avoid social interactions with their peers. The scariest part is that weight stigma may have long-lasting detrimental effects on both physical and mental health throughout the lifespan”, says Dr. Angela S. Alberga postdoctoral fellow at the University of Calgary.

Increased media attention and multi coloured shirt days (pink shirt day – feburary 26th, blue shirt day – October 7th, both marking anti bullying days) have drawn our attention to the bullying cause.

We can always do more.

As a former employee of the Canadian Obesity Network I have had the privilege of being a member of the Sandbox Project’s  Healthy Weights working group as well as CON’s representative in the Obesity Action Coalition working group on Weight Bias and Stigma.

I recently wrote my second children’s book ‘Pom Pom – A Flightless Bully Tale’ in the hope of putting bullies in their place.

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Category: Miscellaneous, News | 1 Comment

3 Ways to Bridge the Behaviour-Intention Gap

Today’s guest post comes from Chetan Mistry and Ryan Rhodes of the University of Victoria.  More on Chet and Ryan can be found at the bottom of this post. This post originally appeared on Fit After Fifty.

Nearly 80% of inactive adults want to be active, yet 50% fail to be active. This phenomenon is known infamously as the “intention-behaviour gap”. The “gap” seems to come full force each year when so-called “January Joiners” rush to the gym to fulfill new years resolutions. Well, January has come, and January has gone.  So what can you do to avoid being a “January Joiner” who falls off of the fitness train and into the “intention-behaviour gap”? Growing research evidence suggests 3 potential strategies to help you to stick to your resolutions.

1. “Find something you enjoy.”

Most people get into exercise for the benefits; weight loss and physical appearance. Yet, these benefits are not related to the actual behaviour or act of exercising, but instead to the long-term outcomes that could result. People may want the outcomes of exercise, but not necessarily the behaviour that goes with it. The people who stick with exercise are those who actually enjoy doing exercise. The reason these people enjoy exercise could be for one of many reasons. They may enjoy the actual activity. For example, some people who play sports enjoy the sport itself, so they continue to run, jump, or kick for the love of the game/sport. To add to it, some of these people play because important others play, too. Whether it be friends, partners or children, exercisers who continue to exercise do so because they enjoy the activity and spending time with the people they exercise with.

To stick to your new years resolutions in 2014, ensure that the exercise you are choosing is something you enjoy. If it isn’t, it is well worth trying something new. Even better, you could try something new with a friend or partner. If finding something new is not feasible, try adding something you enjoy to your current exercise to make it more bearable. Listening to music, watching a movie or TV show, or reading could help to make your next exercise session a more positive experience.

2. “Organize and know thyself”
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Category: News | Comments Off

Daylight savings time increases risk of heart attack. Here’s what you can do to avoid one.

heart-attackDid you know that adjusting the clock up by an hour in accordance with daylight savings time increases you chance of a heart attack?

Circadian rhythms are biological cycles that occur in humans, animals, insects, plants, and even bacteria with a period of approximately (circa) one day (diem). These rhythms are determined internally by a part of our hypothalamus and are synchronized perfectly to our 24-hr days by the sun and other cues. This internal clock mediates daily variation in everything from hormone levels, to sleep/wake cycles, feeding behaviour, thermoregulation, to bowel movements and cardiovascular function, among many others.

It is largely due to these predictable circadian rhythms that risk of a myocardial infarction (heart attack) is significantly highest in the morning (by about 40% as compared to other times in the day). Right as we awake, our cardiovascular system is in the most compromised state –systolic blood pressure and heart rate show the largest upward spike in the morning, blood vessels ability to dilate in response to increased blood flow is compromised (relative endothelial dysfunction), blood clots are more likely to form, and the ability to break them up is at its lowest point in the day. Is it any wonder then, that the first snowfall – shoveled early in the morning by people at risk – always leads to a spike in heart attacks?
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Category: News, Obesity Research, Peer Reviewed Research | 4 Comments