We know that sitting long hours is a health hazard that can lead to early death. What’s been unclear is whether frequent breaks in sit time can reduce that risk even if total sit time remains the same. Researchers from Columbia University Medical Center looked into that question.
Their study, published in the Annals of Internal Medicine (2017; 167 , 465–75), included nearly 8,000 adults aged 45 and over, and the scientists found that the risks of sitting many hours each day were attenuated when inactivity intervals were interrupted at least every 30 minutes with some kind of movement. This study is discussed in detail in the Research column of this issue.
But what is it about sitting that’s so dangerous? Keith Diaz, PhD, the study’s lead researcher and an assistant professor of behavioral medicine at Columbia, responds:
“The reasons why sedentary behavior (or sitting) is harmful to a person’s health are still unclear,” he says. “Some of the best available evidence suggests that our bodies don’t regulate blood sugar levels as well when our muscles (a key regulator of blood sugar levels) don’t get frequent use. And this can have harmful consequences for our organs. Early, promising evidence also suggests that the sitting posture itself can be harmful and damaging to blood vessels because of the lack of blood flow and the blood pooling that occurs when [we sit] for long periods at a time. This may increase the risk of things like peripheral artery disease and deep vein thrombosis.”
Diaz concludes, “The scientific evidence for standing being a healthier alternative to sitting is still somewhat unclear. So, at this point, our best recommendation is that movement breaks are needed to reduce the harmful consequences of prolonged sedentary behavior.”