Meet our writers

Win $1,000







Health August 2012

Aid for Age

Sitting Out Fewer Years of Life

By Tait Trussell

The BMJ Open study is the latest in a string of studies of “sitting disease,” as it might be labeled. If we sat for less than three hours a day, the average life expectancy would be 80.5 years rather than the current 78.5 years, the new study said.

Can sitting for more than three hours a day really kill you? A study in the online journal “BMJ Open” and followed by scare stories in a host of publications said that sitting down for more than three hours a day can shave two years off your life expectancy.

If you limit your time spent watching TV to fewer than two hours a day, you can add an added 1.4 years to your life span, the study also indicated.

“Sedentary behavior is something we need to take note of beyond telling people to get 30 minutes of activity a day, said one of the lead researchers of the study, Peter Katzmarzyk, professor of population science at Pennington Biomedical Research Center at Baton Rouge, Louisiana.

While seniors are urged to exercise some each day, very few elderly aren’t couch potatoes much of most days. So, it’s a bit alarming to read, for instance, that sitting “for more than three hours a day” watching TV or reading can cut our life expectancy.

The BMJ Open study is the latest in a string of studies of “sitting disease,” as it might be labeled. If we sat for less than three hours a day, the average life expectancy would be 80.5 years rather than the current 78.5 years, the new study said.

“Sitting is a dangerous risk factor for early death, on par with smoking and being obese,” said Katzmarzyk — sending a nervous shiver up many a spine.

Other data show that getting up intermittently throughout the day might reduce the risks connected with prolonged sitting. James Levine, a professor of medicine at Mayo Clinic, who did some of the first research on sitting, said, “Sitting is diminishing the health of the nation.”

But “no one knows how much we should be up.”

The researchers used data from the National Health and Nutrition Examination Survey (NHANES) to calculate the amount of time U.S. adults spent sitting down and watching TV on a daily basis. They reportedly pooled risk data from five relevant studies that involved nearly 167,000 adults. The researchers came up with a “population attributable fraction” (PAF), which is an estimate of the theoretical effects of a risk factor at a population level, rather than an individual level, to calculate the number of deaths connected with time spent sitting down.

The results of the analysis indicated that reducing the amount of time spent sitting down every day to under three hours would add an extra two years to life expectancy. And restricting the time one watches TV to under two hours a day would extend life expectancy by an extra 1.38 years.

The authors of the study emphasized that their analysis doesn’t actually prove there is a direct association between sitting and mortality. But the evidence shows a definite detrimental effect of a sedentary lifestyle.

Because Americans sit an average of 55 percent of the day, and most seniors spend more time than that in their chairs, it would take a drastic change in lifestyle to sharply cut the sitting risk.

Words from the American Cancer Society says, “prolonged time spent sitting, independent of physical activity, has been shown to have important metabolic consequences, and may influence” triglycerides, cholesterol, glucose, resting blood pressure, and lipid, “which are biomarkers of obesity ad cardiovascular and other chronic diseases.”

Last year, scientists found that people who worked many years in sedentary jobs had twice the risk of colon cancer and an increased risk of rectal cancer, compared to people who had never worked in sedentary jobs.

There are activities you can take to get off your duff now and then. Stand up during TV commercials, for instance. Walk around while talking on the phone. Get a dog and take it for a long walk each day.

And I have another idea. If you drink eight or more glasses of water each day, as some doctors recommend, nature will force you to get up and visit the bathroom fairly regularly.

 

Tait Trussell is an old guy and fourth-generation professional journalist who writes extensively about aging issues among a myriad of diverse topics.

Meet Tait