Sitting Kills

Here's a new warning from health experts: Sitting is deadly. 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 even die. 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. "After four hours of sitting, the body starts to send harmful signals," Ekblom-Bak said. She explained that genes regulating the amount of glucose and fat in the body start to shut down. Figures from a U.S. survey in 2003-2004 found Americans spend more than half their time sitting, from working at their desks to sitting in cars.