Sitting too long can kill you

Robin Wulffson MD's picture
sedentary lifestyle, sitting, TV watching, longevity, workplace
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Many Americans spend most of their workday sitting at their desk. In the evening, many plop down in front of the TV for several hours after dinner. According to a new study, a sedentary life style can take years off one’s life. Researchers affiliated with the Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, Louisiana and the Division of Preventive Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts published their findings online on July 9 in the journal BMJ Open.

The goal of the research was to determine the impact of sitting and television viewing on life expectancy in the USA. The investigators accessed data from the National Institutes of Health’s National Health and Nutrition Examination Survey (NHANES) from 2005/2006 and 2009/2010, which included nearly 167,000 adults. They found that the average American spends approximately 55% of the day (seven-and-a-half hours) sitting.

After analyzing the data, the researchers determined that the estimated gains in life expectancy in the US population were 2.00 years for reducing excessive sitting to less than three hours a day; furthermore; a gain of 1.38 years could be attained by reducing TV viewing to less than two hours a day. Those figures represented the average gain. The increased life expectancy for less sitting ranged from 1.39 to 2.69 years. The increased life expectancy from less television viewing ranged from 0.48 to 2.51 years.

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Previous studies have linked sedentary behavior with a higher risk of obesity, type 2 diabetes, and cardiovascular disease, which all contribute to increased mortality rates. Lead researcher Dr. Peter Katzmarzyk, a professor of population science at the Pennington Biomedical Research Center, noted that their study demonstrated that prolonged sitting is attributable for 27% of all deaths in the US and that TV viewing is attributable for 19% of deaths. He added that those numbers are comparable to the decrease in life span reported for smoking. In addition, he stressed that simply engaging in moderate exercise once a day is not enough to counteract the negative health effects of sitting.

Dr. Katzmarzyk offered suggestions for increasing longevity. He recommended that individuals should not only be physically active for 30 minutes a day but also should spend less time sitting. He noted that even physically active people incur the added risk if they spend prolonged periods sitting at their workplace. He stressed that the workplace is an area where improvements can be made to decrease time spent sitting and improve health. He noted that many options are available for individuals who want to break up a sedentary lifestyle at the workplace. Some ideas being evaluated include the use of treadmill desks or stand-up desks. Dr. Katzmarzyk suggested walking over to a co-worker’s desk and speaking in person, rather than e-mailing that individual; another concept was to conduct “walking meetings.” He noted that certain occupations are conducive to being active during the workday. These include professions such as nurses, food servers, and construction workers.

Take home message:
This study indicates that a sedentary lifestyle impacts health to a similar degree as obesity, smoking, and type 2 diabetes.

Reference: BMJ Open

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