Prolonged sitting should be avoided, say the researchers of a medical study soon to be announced. The researchers, whose work will appear in the Journal of the American College of Cardiology, studied more than 4,500 people 35 or older for four years and found that people who spent more than four hours a day in front of a computer or TV screen were more than twice as likely to have heart problems as people who spent more time in motion. Moderate daily exercise, long thought to be somewhat of an antidote to such sitting-associated dangers, didn't seem to make a difference, the researchers reported.
Further, the study found that people who sit for even two hours at a time can increase their risk of heart problems — the more sitting, the higher the risk.
Sitting for long periods of time at a stretch can hinder the body's ability (through production of an enzyme called lipoprotein lipase) to break down fats, such as cholesterol. So-called "couch potatoes" further complicated their situations by, in many cases, eating high-cholesterol foods while sitting — in effect giving the body more fat to break down but fewer enzymes to do it. The fact that people who watched television were more likely to see ads for junk foods compounded the problem.
This is not the first study of its kind. Scientists have long held that too much inactivity is harmful to the body, for the precise reasons cited in this latest study. However, many researchers had generally believed that exercise done at least once a day could help offset that potential harm. According to this latest study, that exercise makes a difference in overall health but, because it isn't interspersed with the prolonged sitting, doesn't address the inhibition of enzyme production.
The study incorporated sitting only in a leisure context, meaning that participants didn't comment on how much and how long at one time they sat while doing their jobs. In today's increasingly computer-based society, such prolonged on-the-job sitting (even sitting behind the drive while commuting to and from work) could be even more of a danger.
The answer, many researchers would say, is to not let the sitting get too prolonged: break up time spent in front of the computer or TV into smaller segments.