Don't sit for long stretches; get up and move every so often

Cost

Free, and getting up a few times takes little time. The hard part is that once you sit down you lose track of time, so set a reminder.

What you get

A U.S. follow-up study (observational, not assigning groups) measured sitting with accelerometers. People were split into four groups by total daily sitting time. The group that sat the most had 2.63 times the risk of death of the group that sat the least (HR 2.63). Split again into four groups by how long they sat in one stretch, the group with the longest stretches had 1.96 times the risk of the group with the shortest (HR 1.96). So total sitting and the length of each stretch are each linked to risk on their own. Another analysis pooled studies covering over a million people, also observational. People who sat 8 or more hours a day and barely exercised had 1.59 times the risk of death of another group (HR 1.59). That other group sat less than 4 hours a day and was the most active. About 60–75 minutes of moderate activity a day can cancel out the extra risk from sitting. In the most active group, even those who sat 8 or more hours a day had an HR of only 1.04, with no statistically significant difference.

Notes

The reliable conclusion is that how much you move matters more than how long you sit, and with enough exercise the risk from sitting mostly disappears. Keep in mind that these studies only followed people. Many of those who sat the most were already ill, and the “risk as high as 2.63 times” clearly includes people who sat because they were sick first. Also, in the same pooled analysis, the risk from watching TV 3 or more hours a day was present at every level of exercise, and the most active group only pushed that starting point out to 5 hours.

Evidence grade

A : Specific numbers from meta-analyses, large cohorts or randomized trials; for law and policy, the statute or official text.

Sources

1. Diaz KM 等 (2017). Patterns of Sedentary Behavior and Mortality in U.S. Middle-Aged and Older Adults: A National Cohort Study. Annals of Internal Medicine. https://doi.org/10.7326/M17-0212
2. Ekelund U 等 (2016). Does physical activity attenuate, or even eliminate, the detrimental association of sitting time with mortality? A harmonised meta-analysis of data from more than 1 million men and women. Lancet. https://doi.org/10.1016/S0140-6736(16)30370-1

Translated from the Chinese original. Original book, section 2, tip 17. This section is about health and medicines. It is general information, not a substitute for a doctor’s diagnosis or prescription. Content may be out of date and rules differ by place. When you actually deal with an agency, a doctor or a court, follow what local officials, doctors and lawyers tell you. Disclaimer