Experts: Sitting too much could be deadly

LONDON — Scientists are increasingly warning that sitting for prolonged periods — even if you also exercise regularly — could be bad for your health. And it doesn't matter where the sitting takes place — at the office, at school, in the car or before a computer or TV — just the overall number of hours it occurs.

Research is preliminary, but several studies suggest people who spend most of their days sitting are more likely to be fat, have a heart attack or die prematurely.

In an editorial published this week in the British Journal of Sports Medicine, Elin Ekblom-Bak of the Swedish School of Sport and Health Sciences suggested that authorities rethink how they define physical activity to highlight the dangers of sitting.

While health officials have issued guidelines recommending minimum amounts of physical activity, they haven't suggested people try to limit how much time they spend seated.

"After four hours of sitting, the body starts to send harmful signals," Ekblom-Bak said, explaining that genes regulating glucose and fat in the body start to shut down.

Even for people who exercise, spending long stretches sitting at a desk is harmful. Tim Armstrong, a physical- activity expert at the World Health Organization, said people who exercise every day — but spend a lot of time sitting — might get more benefit if that exercise were spread across the day, rather than in a single bout.

That wasn't welcome news for Aytekin Can, 31, who works at a London financial company and spends most of his days sitting in front of a computer. Several evenings a week, Can also teaches jiujitsu, a Japanese martial art involving wrestling, and does Thai boxing.

"I'm sure there are some detrimental effects of staying still for too long, but I hope that being active when I can helps," he said. "I wouldn't want to think the sitting could be that dangerous."

Figures from a U.S. survey in 2003-04 found Americans spend more than half their time sitting, from working at their desks to sitting in cars.

Experts said more research is needed to figure out how much sitting is dangerous, and what might be possible to offset those 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 said. "Don't just send your colleague an e-mail. Walk over and talk to him. Standing up."