Prolonged sitting is considered detrimental to health, but evidence regarding the independent relationship of total sitting time with all-cause mortality is limited. This study aimed to determine the independent relationship of sitting time with all-cause mortality.
… We linked prospective questionnaire data from 222 497 individuals 45 years or older … to mortality data …
During 621 695 person-years of follow-up …, 5405 deaths were registered…. The association between sitting and all-cause mortality appeared consistent across the sexes, age groups, body mass index categories, and physical activity levels and across healthy participants compared with participants with preexisting cardiovascular disease or diabetes mellitus.
Conclusions Prolonged sitting is a risk factor for all-cause mortality, independent of physical activity. Public health programs should focus on reducing sitting time in addition to increasing physical activity levels.
I’ve left out the numbers … briefly, if this study is correct and accurate, sitting for more than 11 hours a day measurably reduces lifespan compared to sitting for less than 4 hours a day. For the age group looked at, if you were a long-sitter you had a 40% greater chance of being dead within 3 years than if you sat very little in a given day. This does not mean a 40% chance of being dead … just 40% more than whatever it was. For lesser differences in sitting time, the difference in mortality risk is lesser as well.
I’m not sure how this translates into practical advice and I’m not sure this study alone provides enough information to answer that question. One way to think about this is as follows: If you sit many hours a day because of your job, how much of that sitting time do you need to change into standing time to make a difference, and can standing alone vs. moving around do the trick? Once that is established, perhaps one could create a standing version of one’s workspace.
I know what you are thinking: “I go to the gym for five hours a day so that fixes that problem.” Sorry, but no. Apparently (and this is not fully demonstrated, so this is something of a guess) it’s the sitting that hurts you, independently of the lack of exercise. Yes, those several hours a week of exercise helps you and makes you healthier, but the sitting itself, if we’ve got this right, is a bad thing, with negative effects, and if you do too much off that every day you’ll die sooner than otherwise.
Suggestions? Comments? Questions? Criticisms? Do you know of other research on this?