Health experts have issued a new warning: Sitting is deadly. Researchers now have evidence that sitting for prolonged periods can be harmful to your health, even if you also exercise regularly. And it doesn’t seem to matter where you sit — in the car, at the office, at school — just that the sitting lasts for several hours.
Research is preliminary, but some studies are showing that people who spend much of their day sitting are more likely to be fat, have a heart attack, or even die.
One study of more than 17,000 Canadians covering a dozen years found that people who sat more had a higher death risk, independently of whether or not they exercised. “We don’t have enough evidence yet to say how much sitting is bad,” said Peter Katzmarzyk of the Pennington Biomedical Research Center in Baton Rouge, who led the Canadian study. “But it seems the more you can get up and interrupt this sedentary behavior, the better.”
In an editorial published recently in the British Journal of Sports Medicine, Elin Ekblom-Bak of the Swedish School of Sport and Health Sciences suggested that health experts rethink how they define physical activity in order to highlight the dangers of excessive sitting.
“After four hours of sitting, the body starts to send harmful signals,”Ekblom-Bak said. The genes regulating the amount of glucose and fat in the body start to shut down, she added.
Tim Armstrong, a physical activity expert at the World Health Organization, stated that even for people who exercise, sitting for long stretches still is harmful. He suggested that they may get more benefit if the exercise were spread across the day, rather than in one single session.
Statistics from a 2004 survey found that Americans spend more than half their time sitting, from working on computers to watching television to driving in cars.
Experts called for more research to determine how much sitting is dangerous and what might be done to counteract the effects.
“People should keep exercising because that has a lot of benefits,” Ekblom-Bak said. “But when they’re in the office, they should try to interrupt sitting as often as possible,” she added. “Don’t send your colleague an email. Walk over and talk to him. Standing up.”