To Sit Or Not To Sit, That Is The Question
This is where things get frustrating. Two recent studies, taken together, are enough to leave us paralyzed with confusion:
In the first we learn that prolonged standing on the job is more likely to lead to heart attack than prolonged sitting; and the second tells us that prolonged sitting increases the risk of early death.
What the heck is going on? Should we just give up on trying to be healthy?
The answer, as usual, seems to lie in finding an appropriate balance.
In the first study, Canadian researchers found that people who predominantly stand all day at work put added stress on their heart. Blood tends to pool in the legs during prolonged, inactive standing, causing the heart to work harder. The result over the long term, even accounting for other factors, is a doubled risk of heart disease compared with people whose occupations involve primarily seated work.
The second, unrelated study seems to have gotten more publicity, with many stories highlighting the benefits of getting up from your chair at least once every thirty minutes. The study, funded by the National Institutes of Health, examined the effects of “total sedentary time” and “sedentary bout time” — and concluded that both were associated with a higher risk of all-cause mortality. Basically, doing a lot of sitting or doing your sitting in long, uninterrupted blocks increase your risk of death. Even people who exercise regularly are put at risk by jobs that require them to remain seated for much of their work day.
The bottom line is that if you have to sit a lot, it’s bad for your health; but you can mitigate some of the negative effects by breaking your sedentary time up into short blocks.
“Both the total volume of sedentary time and its accrual in prolonged, uninterrupted bouts are associated with all-cause mortality,” the study concludes, “suggestive that physical activity guidelines should target reducing and interrupting sedentary time to reduce risk for death.”
So sit less; and when you are sitting, get up at least once every half hour.
And as for those people have to stand all day?
“A combination of sitting, standing and moving on the job is likely to have the greatest benefits for heart health,” says Institute for Work & Health (IWH) Senior Scientist Dr. Peter Smith, who led the “standing” study. “Workplaces need to apply this message not just to workers who predominantly sit, but also — in fact, especially — to workers who predominantly stand.”