Britain releases Expert Statement on workplace sedentary behaviour

Last week an Expert Statement commissioned by Active Working CIC and Public Health England was published in the British Journal of Sports Medicine titled “The Sedentary Office: a growing case for change towards better health and productivity” (available here).

From the Get Britain Standing website:

Based on the current evidence Active Working recommends:

  • 2 hours daily of standing and light activity (light walking) during working hours, eventually progressing to a total of 4 hours for all office workers whose jobs are predominantly desk based
  • Regularly breaking up seated based work with standing based work, with the use of adjustable sit-stand desks/work stations
  • Avoidance of prolonged static standing, which may be as harmful as prolonged sitting
  • Altering posture/light walking to alleviate possible musculoskeletal pain and fatigue as part of the adaptive process
  • As well as encouraging staff to embrace other healthy behaviours, such as cutting down on drinking and smoking, eating a nutritious diet, and alleviating stress, employers should also warn their staff about the potential dangers of too much time spent sitting down either at work or at home

I generally think these are a pretty good thing, and seem to match up with the available literature.  I’m a bit surprised to see guidelines this soon in the game (research is really just getting going on this particular issue, so there will likely be a lot more/better evidence in a couple years, at which point this guideline will have already taken hold), but there’s nothing in there that seems really off base from my reading of the literature.  And I think it’s good that they highlighted the potential downside of prolonged standing as well as prolonged sitting.

Now the real question is whether following these guidelines will have any actual health impact (lots of reasons to think it might, but the research isn’t really there yet as far as I have seen).  That being said, I am using my standing desk to write this because there is plenty of evidence to think that standing is probably a good idea at least part of the time. And lots of good acute studies showing benefits of standing/walking.  We just don’t know if that translates into long-term benefits.

As a colleague likes to say, data clusters around data. Once people put out a recommendation like this, everyone else tends to publish data to evaluate that specific recommendation, with the result that research published in the next few years is likely to cluster around the specific recommendations of the guidelines, rather than looking at other volumes of sedentary behaviour (e.g. in the past people might look at the benefit of being above or below 3 hours/day of workplace sitting time; I would bet that future studies will focus on 2 and 4 hours, to be in line with these guidelines). So at the very least, this guideline will likely prompt people like me to study whether following these guidelines actually benefits people, at which point the guidelines will likely be tweaked or vindicated.

The full Expert Statement is available here.

Travis

Category: News, Sedentary Behaviour | 4 Comments

Participants wanted for text message physical activity study

15 06 09 study ad

Travis’ Note: University of Victoria student Chetan Mistry is looking for participants to take part in his text message intervention as part of his PhD thesis.  The details are below.

Chetan Mistry and the Behavioural Medicine Lab at the University of Victoria (BC) are seeking participants for an exercise planning study, delivered entirely via mobile phone through text messages! The study could help you to stay on top of your exercise by planning and monitoring your daily habits.

If you have a mobile phone with access to text messaging and the internet, participated in LESS than 150 minutes of physical activity per week over the past month, and are motivated to be MORE active during the next month, you may qualify to participate in the study.

The study involves one baseline survey (~20 minutes) and daily exercise recall/planning surveys (2-3 minutes) for 30 days. The daily surveys are not mandatory, so you can do as many as you can manage. If you are interested in participating, you may begin by completing the baseline survey here: http://fluidsurveys.com/s/BL/

For more info, please contact chet@uvic.ca. Thank you!

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Stop killing the elderly with kindness

Life partners for infinity (CC)

Update: the title of this post has been changed in response to a comment in the discussion.

This past winter I taught a course titled Physical Activity and Aging.  It was a fun course, and really drove home an issue that I’ve known for a while, but hadn’t previously given a lot of thought: the impact of aging is identical to the detraining that happens in response to reduced physical activity and/or increased sedentary behaviour.

Aging is associated with reduced fitness, weaker bones, reduced insulin sensitivity, reduced muscle strength, and reduced balance.  Lack of physical activity is also associated with all of those things.  This isn’t a coincidence – many (probably most) of the health impacts of aging are not really due to aging at all.

You see, there are 2 types of aging.  Eugeric aging, which you can think of as “true” aging. The stuff you simply cannot avoid as you get older (e.g. hearing loss, or reduced eyesight).

But there is also “pathogeric” aging, which refers to pathological aging (e.g. aging that’s unecessary/unhealthy).  Almost all the really scary things that we attribute to aging (weak bones, bones, heart, lungs, etc) falls into this category, and are much more likely to be caused by too little exercise/too much sitting, rather than aging itself.

I bring this up because I’m concerned that we are currently killing our elders with kindness.  We don’t let them carry their dishes to the sink (“Mom, sit down! I can get that!”).  We won’t let them do chores.  We worry if they have to go up and down stairs on a daily basis.  We get angry if they go for a walk without a chaperone.  We force them to sit to conserve their energy.  All of this flies in the face of evidence, and common sense. Picture the healthiest older adult that you know – do they spend their day sitting down, or do they spend their days walking, skiing, or dancing?  It’s not a coincidence.

If I were to take a healthy 20 year-old, force them to sit all day, and refused to let them do any physical labour out of fear they might hurt themselves, I would cause them to “age” extremely rapidly.  We call it detraining, and we’ve known about it for decades.  Put a healthy young person in a bed for less than a week and their metabolic health goes to hell – blood pressure increases, as does the amount of fat in the blood, while insulin sensitivity plummets by over 65% (details here).  And yet that’s the life that we often push upon the elderly out of fear that they might hurt/tire themselves out of they engage in too much physical activity (fun fact – exercise helps you sleep better, which is a good thing at all ages!).

What’s worse, there is often a vicious cycle – a person does less activity as they age, which causes reduced fitness.  That reduced fitness makes it harder to be active, so their activity levels drop more.  Which means fitness drops more.  And then muscle strength starts to slip. Which means even less activity, further reductions in fitness, and difficulties doing activities of daily living, or even living independently.  You get my point.  The good news? Even modest amounts of exercise result in increased functional and aerobic fitness, as well as improved metabolic health (details here).

We need to promote more, not less physical activity for our elders.  We should cheer them on when they decide to do physical chores, and encourage them to do more. The next time to consider telling your grandmother to sit down, think about whether that’s really in her best interest.

Travis

Category: News | 18 Comments

Do mini-packaged snacks help you eat less junk?

Doritos-100kcalIn recent years countless food manufacturers have been “sub-packaging” their foods into smaller portions in an apparent effort to curb folks from overindulging. You can usually find 100 kcal multi-packs of chips, pretzels, chocolates, and all sorts of junk foods. Despite the very obvious negative environmental impact of all this excess packaging, what, if any, impact does such packaging have on people’s consumption.

Thankfully, Wansink and colleagues had previously published a paper in the journal Obesity investigating this very question.

I previously discussed another study by Wansink that essentially showed that when snacks are served in bigger bowls, people tend to eat more of their contents.

Thus, it would seem reasonable to think the reverse was also true in terms of small packages for snacks, as in the case with these hyper-packaged 100kcal bags of junk.

So the same authors sought to address this issue, and also to check if the effect on consumption of small packages differed between overweight and normal weight individuals.

A total of 42 undergraduate students participated in the simple study which basically had the participants snack on crackers while watching a sitcom – now THAT is what I call research!

Half of the participants were given one large 400-calorie package of crackers or a similar-sized package that had then been sub-divided into four smaller 100-calorie sub-packaged crackers. They were blinded to the purpose of the study.

After watching the show, the crackers not consumed by the participants were counted to calculate everyone’s caloric intake. Also, each participant was asked how many crackers they think they consumed.

Turns out, overweight participants ate significantly more crackers when eating from one large package than from four small packages. In fact, they consumed more than double the number of calories with the bigger package: 384 calories versus 176 calories.

Surprisingly, there was no difference in consumption between package conditions among the normal-weight participants.

Despite this difference in consumption, what is odd is that all groups (small package and big package, overweight and normal weight) underestimated how many crackers they had eaten by more than 60%!

This suggests that the smaller packaging doesn’t make people more accurate at keeping track of what they ate.

So why the difference between overweight and normal weight participants?

The authors suggest the following:

“Obese people were more likely to rely on external cues to stop eating, [and thus] the perception of package count might play a crucial role for overweight participants in determining their food intake.”

Peter

Reference:

Wansink, B., Payne, C., & Shimizu, M. (2011). The 100-Calorie Semi-Solution: Sub-Packaging Most Reduces Intake Among The Heaviest Obesity DOI:10.1038/oby.2010.306

Category: nutrition, Obesity Research, Peer Reviewed Research | 5 Comments

Why you crave tomato juice on an airplane

tomato juiceI’m writing this seated on a plane heading to San Francisco. We’ve been in the air for under an hour, and the drink cart is just starting to make its way down the aisle. As the cart rolls nearer I’m forced to decide what drink I’ll be having. Since the cups are miniscule, and the liquid is largely displaced by ice cubes if one’s not quick enough to add “no ice, please” to the order, the decision is critical.

Despite the fact that I never drink tomato juice on the ground, I’m once again craving the drink in mid air. In fact, on the very first flight I took as a kid – from Athens, Greece to Toronto back in 1991 – I distinctly remember ordering tomato juice. Now, why would a 10-year old kid crave tomato juice? And why am I now having the same craving?

It has been known for some time that there exists overlap between our senses in how we perceive the world. For instance, it is well-established that the visual appearance of food influences the perception of flavour. Ever made the error of having three things on your plate of broadly the same colour? There’s just something very unappetising about it, and the flavour never seems as rich as expected. The role of our olfactory sense in the perception of flavour is well illustrated by the blandness of most food when we have a cold and are noses are congested. Differing textures are also helpful in making food more appetising.

So what about the flight experience might be playing havoc with our perception of taste and thus our craving for certain flavours. The answer, according to some recent research, appears to be cabin noise.

In the study, Yan and Dando assessed the effect of loud audio stimulation on the perception of the five basic tastes.

A total of 48 men and women evaluated multiple standardized solutions for perception of sweet, salty, sour, bitter, and umami flavours, on a validated scale while in silence (condition A) or an environment that replicated conditions found during airplane flight and landing (condition B). Specifically, cabin noise was recreated from actual airplane cabin noise recordings, delivered to participants at 80 to 85 dB through high-definition headphones.

And what did the research reveal?

First, noise that one might experience onboard an airplane seems not to affect our perception of salty, bitter, and sour flavours.

However, exposure to loud noise caused a pronounced suppression of sweetness intensity across all concentrations measured. Ever noticed how all pop drinks taste like their diet (low or no-sugar) equivalents while in the air?

Conversely, loud noise was found to increase the perceived intensity of umami flavour, found in foods and drinks containing monosodium glutamate (MSG).

Thus, the popularity of umami-rich drinks such as tomato juice onboard airplanes may be the combined result of enhanced umami taste and dulled sweet taste.

These findings may also explain the consistently poor ratings of airplane food. Then again, the cardboard that passes for chicken on planes is likely to taste just as awful on the ground as it does at 30,000 feet.

And finally, the level of noise at restaurants may also influence the flavours perceived in the foods served. Theoretically, a loud restaurant would do well to serve umami-rich foods, but focus less on desserts and sweets.

Or you could just bring industrial-strength ear plugs with you everywhere and avoid noise affecting your meal altogether.

Peter

Reference: Kimberly S. Yan and Robin Dando. 2015.  A Crossmodal Role for Audition in Taste Perception. Journal of Experimental Psychology: Human Perception and Performance.
Advance online publication. http://dx.doi.org/10.1037/xhp0000044

Category: News, nutrition, Obesity Research, Peer Reviewed Research | 2 Comments

Juice ≠ Fruit (!!!)

orange juice

Word emerged last week that Health Canada was re-considering whether it should continue to view a serving of juice (125 ml) as being equivalent to a half cup of fresh/frozen fruit.  I think this would be a wonderful development, and I believe that my own personal experience helps to explain why.

While I was growing up, I drank a lot of juice.  Over a litre a day.  During my university days, I often bought 10 or more litres of juice in a given trip to the grocery store. Whenever my roomates poked fun at all that juice consumption (which was often), I would point to the sticker on the carton stating that it was the nutritional equivalent of eating a serving of fruit.  The calories shouldn’t count, because…. fruit.

That was then.  My thinking has changed somewhat in the intervening years.  Now, I realize that drinking a small bottle of orange juice is the equivalent of eating 6 oranges, which would strike most people as excessive.  In contrast, the amount of juice in a single orange is rather pathetic:

The amount of juice in one orange

Further, a glass of Tropicana has more calories than an identical glass of Coke or Pepsi.

Calories & Sugar in 12 ounces of Coca-Cola, Pepsi, and Tropicana

And what about smoothies?  As I’ve said in the past:

Even a freshly made fruit smoothie is still pretty refined when compared to the fruit itself. It takes a fair amount of energy and chopping (not to mention a fancy modern blender) to get a pineapple to the point that you can consume it through a straw.  You can think of a fruit smoothie as essentially a piece of blueberry pie in a glass – at least in the pie the blueberries aren’t liquefied (seriously – an original size strawberry raspberry banana smoothie at Jamba Juice has more calories and more sugar than a piece of homemade blueberry pie). Smoothies may be a lot less refined than Twinkies, but they’re not all that far from Nutella or peanut butter.

So let’s all hope that Health Canada decides to make the common sense move, and stop considering juice and fruit to be nutritionally equivalent.

Travis

Category: News | 2 Comments