"Spending lots of free time glued to the TV or computer screen can hurt your heart and shorten your life, no matter how much exercise you get when you're not riding the couch, a new study suggests."
See Too much TV time may hurt your heart by Anne Harding. The research was done by Emmanuel Stamatakis, Ph.D., an epidemiologist at University College London. The article also says:
"Why is sitting harmful? It's not entirely clear, but animal studies have shown that prolonged sitting slows down the action of an enzyme (lipoprotein lipase) that breaks down fats in the blood, such as cholesterol and triglycerides. When the enzyme activity slows, levels of those substances climb. This is a "very plausible explanation" for the findings, Stamatakis says."
It concluded with "Stamatakis and his colleagues are now investigating whether getting up and walking around or even just standing can help counter the ill effects of sitting."
But just today another article came out about research which says that taking breaks will help. See Taking Short Breaks From Sitting May Help Waistline and Heart: Even a little more activity spread through the average workday boosts health, study suggests by Alan Mozes.
This research was done by Genevieve N. Healy, of the Cancer Prevention Research Centre at in the School of Population Health at the University of Queensland in Herston, Australia.
""This research suggests that even small changes to a person's activity levels [as little as standing up regularly] might help to lower cardiovascular risk. These changes can be readily incorporated into the person's day-to-day life [including the work environment]. Stand up, move more, more often, could be used as a slogan to help get this message across.""