We’re starting to understand how sitting too much can put your health at risk. The good news is that the solution is simple.
For the past 60 years or so, researchers have been studying the health benefits of physical activity. I am talking about any type of physical activity – walking, cycling, housework, etc – and not just “exercise”.
No surprise, people who are physically active tend to live longer, healthier lives than those who are inactive. What’s more, substantial health benefits come from even small amounts of physical activity. The health benefits of physical activity are so impressive that until recently, we believed that it didn’t really matter what you did the rest of the time, so long as you got in a workout at some point in the day.
In the past 10 years or so, however, we’ve begun to realize that it’s not quite so simple. Physical activity is still amazingly good for you. But we’re starting to realize that the rest of the day matters as well.
For example, take the figure below from a study of 17,000 Canadians. At baseline, all participants were asked how much time they spend sitting on a daily basis. Researchers then followed them for the next 12 years, and found that those who sat the most had 55 per cent higher risk of death than those who sat the least.
You might wonder whether those who sat the least were also the most physically active, which could explain why those people had lower risk of dying during the follow-up period. That doesn’t seem to be the case though.
The figure below shows the same data, but this time broken into people who were physically active (in red) and those who were physically inactive (in blue). The active people had a lower risk of death over all (the red bars are generally lower than the blue bars), which supports the idea that activity is really good for you. But even among those active people, the risk of death increased as daily sitting time increased.
So physical activity is good for you, but your risk of death still goes up the more time you spend sitting. The best situation is to get at least some amount of physical activity, while trying to minimize your sitting time as much as possible.
Lots of other studies have supported these findings, including a recent Canadian paper that combined the results of 47 different studies, concluding that sedentary behaviour increases the risk of heart disease, diabetes, and premature death even among those who are physically active.
What does this all mean? On the downside, it means that sitting is bad for your health. But the flip side is that it is probably easier to sit less than to do more physical activity. You don’t need a gym membership or special equipment to spend less time sitting. And research suggests that even just breaking up your sitting time (for example, getting up off the couch every 20-30 minutes for a short walk) has measurable health benefits, especially related to blood sugar levels.
Something as simple as watching a bit less TV could actually improve your health. Watching TV seems to stimulate food intake, so the more TV you watch the more likely you are to overeat. It might also make it harder to fall asleep, which can further impact both appetite and activity levels the next day.
So if you’re looking for a simple way to improve your health, try to cut back on your TV viewing (especially before bedtime), and take frequent breaks to get up and move around when you do watch TV. And when you’re ready, add in a bit of physical activity for the complete package.