Interesting article this morning in the NYT about the negative effects of extended sitting. Even people that exercised regularly suffered high rates of premature death when they spent extended time sitting over long periods. http://www.nytimes.com/2012/04/29/sunday-review/stand-up-for-fitness.html?_r=1&ref=health
Just getting up and walking about for a few minutes each hour or two is apparently enough to offset many of the negative health consequences of sitting.
To see the results of such inactivity, scientists with the National Cancer Institute spent eight years following almost 250,000 American adults. The participants answered detailed questions about how much time they spent commuting, watching TV, sitting before a computer and exercising, as well as about their general health. At the start of the study, none suffered from heart disease, cancer or diabetes.
But after eight years, many were ill and quite a few had died. The sick and deceased were also in most cases sedentary. Those who watched TV for seven or more hours a day proved to have a much higher risk of premature death than those who sat in front of the television less often. (Television viewing is a widely used measure of sedentary time.)
Exercise only slightly lessened the health risks of sitting. People in the study who exercised for seven hours or more a week but spent at least seven hours a day in front of the television were more likely to die prematurely than the small group who worked out seven hours a week and watched less than an hour of TV a day.
Just getting up and walking about for a few minutes each hour or two is apparently enough to offset many of the negative health consequences of sitting.