A recent study suggests sitting may not be the grim reaper it’s been declared to be — as long as you also get lots of moderate-to-vigorous physical activity (MVPA).
According to the Whitehall II study, published in the International Journal of Epidemiology, many previous studies linking prolonged sitting to mortality were conducted primarily on sedentary subjects.
The Exercise Effect
The study followed 5132 men and women — all employed by the London-based British Civil Service — for 16 years. When the study began, all subjects were free of cardiovascular disease. Researchers looked at 5 different measures of sitting time: at work, during leisure, watching TV, during non-TV-watching leisure, and work plus leisure. None of these measures was associated with increased mortality risk.
Overall, these subjects were unusually active, averaging 14 hours/week of MVPA — including activities like housework and yard work — in addition to 40-44 minutes of daily walking, which was measured separately. The authors point out that total energy expenditure has long been inversely associated with mortality risk; it makes sense that these participants’ high volumes of physical activity could protect against the negative effects of sitting.
The authors aren’t commenting on the effect of prolonged sitting and disease risk, but acknowledge the possibility that extended sitting could have a negative effect on disease incidence without increasing mortality.
With frequent admonitions about the dangers of sitting, many workers are clamoring for treadmill desks, under-desk pedals, and apps that buzz when they’ve been on their behinds for too long. We’re terrified that sitting at work or — gasp — enjoying an episode of Downton Abbey will doom us to an early grave, even with a solid habit of running, biking, or swimming.
Don’t get me wrong; I’m absolutely in favor of moving more and sitting less. Breaking up extended periods of sitting feels good — and studies point to promising interventions that can help offset negative effects of too much seat-time.
But for active people with jobs that involve extended sitting, it seems warnings of early death by sitting may be overblown… and unhelpful. Active people who are forced to sit tend to fidget — getting up and down frequently, standing and stretching, and jiggling their feet, all of which contribute to daily total energy expenditure. If they’re already doing what you’re hammering on them to do, they’ll tune you out.
What to Do
It’s no secret that most people need more exercise; only 1 in 5 American adults meet recommended minimum daily physical activity levels. Sedentary people with sedentary jobs need to move more, for a variety of reasons that go beyond avoiding early mortality — feeling their best, enjoying a better quality of life, etc. For active people, breaking up sitting time doesn’t hurt, either. Here’s how to help: