Mounting evidence suggests that being sedentary contributes to cardiovascular disease and diabetes, including morbidity and mortality, the American Heart Association (AHA) concludes in a new science advisory that encourages people to sit less and move more.
"The AHA commissioned the paper to evaluate the strength of the evidence regarding sedentary behavior and disease outcomes," Deborah Rohm Young, PhD, who chaired the science advisory, told Medscape Medical News.
"There is compelling but not yet conclusive evidence that too much sedentary time contributes to adverse disease outcomes, but we don't yet know how much is too much," said Dr Young, director of behavioral research at Kaiser Permanente Southern California in Pasadena.
"Clinicians should encourage their patients to accomplish at least 30 minutes of moderate to vigorous physical activity per day. They also should encourage them to move more throughout the day as they're able; sit less, move more," she said.
The advisory was published online August 15 in Circulation.
US adults spend an average of 6 to 8 hours per day sitting, and those over age 60 years spend 8.5 to 9.6 hours per day in sedentary time, the authors note. There is cross-sectional evidence that psychological well-being is inversely associated with sedentary behavior.
Accumulating prospective evidence suggests that sedentary behavior may be associated with increased risk of developing cardiovascular disease, impaired insulin sensitivity, and diabetes and an overall higher risk for premature death from any cause, they point out.
"Regardless of how much physical activity someone gets, prolonged sedentary time could negatively impact the health of your heart and blood vessels," Dr Young said in an AHA news release.
However, there currently is not enough evidence on which to base specific public health recommendations regarding the appropriate limit to the amount of sedentary time to achieve health benefits, the authors say.
Data also suggest that moderate to vigorous physical activity does not cancel out the impact of sedentary time. Even physically active people who spend a lot of their time being sedentary appear to have increased risk, the authors say. And it's not clear at present whether people should replace prolonged sedentary behavior with simple movement or moderate to vigorous physical activity, they note.
"There's a lot of research that we need to do," Dr Young said. "This statement is important because it starts the ball rolling and suggests sedentary behavior may play an important role in heart health and more. But, it's too early to make conclusive recommendations other than to encourage Americans to 'sit less, move more.'"
Clear Actionable Advice
Reached for comment, David L. Katz, MD, MPH, director, Yale University Prevention Research Center in New Haven, Connecticut, told Medscape Medical News that "evidence is accumulating, and has been for some time now, that being sedentary for extended periods each day, and in particular sitting, is bad for health. Conversely, there is also accumulating evidence that getting up and moving at least periodically attenuates this risk."
"We have also long had evidence, of course, that routine exercise (or 'physical activity') confers considerable health benefit. There are also suggestions that routine bouts of exercise may go a long way toward defending against the harms of too much sitting," said Dr Katz, who was not involved in developing the science advisory.
"The best formula," he added, "looks to be both moving routinely, and exercising habitually. But while this is likely the perfect standard, we should not make it the enemy of good. People willing and able both to stand and move throughout the day, and exercise once a day, are likely to benefit from both. People obligated to sit routinely, but able to exercise once per day, will certainly benefit from that exercise."
"But there is also a segment of the population not yet inclined to exercise, who might be willing at least to get up and move periodically," Dr Katz said. "More research will help refine the ideal prescription for this group, but for now, I fully endorse the rather simple suggestion served up by the AHA: sit less, move more. It's clear, actionable, and of almost certain benefit compared to prevailing norms."
The authors have disclosed no relevant financial relationships.
Circulation. Published online August 15, 2016. Abstract
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Cite this: AHA Science Advisory: 'Sit Less, Move More' - Medscape - Aug 24, 2016.