If you follow this blog regularly, you’ve read my warnings about studies showing the health risks of sitting around all day — watching TV, tapping out e-mails, or reading a juicy beach novel. Now new research suggests that 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. A study published online last Monday in the open access version of the British Medical Journal combined the results of five previously published population studies in an attempt to determine how much of an impact TV viewing and excess sitting have on our lifespan. 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. What’s more, this finding “should not be interpreted to mean that people who are more sedentary can expect to live 1.4 or 2 years less than someone who does not engage in these behaviors,” the researchers from Brigham and Women’s Hospital in Boston and the Pennington Biomedical Research Center in Baton Rouge, La., wrote in the journal article. “Life expectancy is a population statistic and does not apply to individuals.”