By Deborah Kotz Globe Staff

If you follow this blog regularly, you’ve read my warnings about the health risks of sitting around all day -- watching TV, tapping out e-mails, or reading a juicy beach novel. Specifically, reasearchers have shown that office workers who neglect to get up and walk around from time to time have more heart-damaging inflammation than the office pacer, and some studies have suggested that Anericans’ sedentary habits contribute to our shorter lifespan compared with the Japanese or French, who live longer and move about more.

Now a new study turns all this bad news on its head by identifying how much cutting back on TV viewing and sitting time is linked to a longer lifespan. Short answer: Sitting fewer than three hours a day is associated with a gain of two years in life, and watching fewer than two hours of TV a day yields an additional one year, four months, and 19 days.

That’s according to a study published online Monday in the open access version of the British Medical Journal, which combined the results of five previously published population studies that observed sitting time and TV viewing habits to see how they correlated with a person’s lifespan -- in an attempt to determine how much of an impact these two habits have on how long we live. I say “attempt” since these studies all merely made statistical associations and couldn’t prove that it was the excess TV viewing or sitting -- and not some other factor such as excessive consumption of potato chips -- that led avid TV watchers to die earlier than most.