The Amount of Exercise Needed to Reduce All-Cause Mortality

This article originally appeared in    http://www.medscape.com/viewarticle/875779

According to Dr. JoAnn Manson, professor of medicine at Harvard Medical School, Brigham and Women’s Hospital, two recent reports from the UK (England and Scotland) shed light on several key questions about physical activity and health, including how much, how often, and what type is best.

Current physical activity guidelines, recommend moderate-intensity exercise for about 30 minutes most days of the week (a total of 150 minutes/week) or vigorous exercise for half that amount of time (75 minutes), spread out over three or more sessions per week. In a report published in JAMA Internal Medicine,^[1] researchers asked a large cohort of more than 63,000 men and women over age 40 about their moderate to vigorous physical activity. Participants were classified into one of four groups: those who did no moderate or vigorous physical activity, those who met the guidelines (150 or 75 minutes/week) and exercised at least three times per week, those who met the guidelines but compressed the activity into one to two sessions per week (commonly referred to as “weekend warriors”), and those who reported some moderate to vigorous physical activity but less than the guidelines.

The results were surprising. All of the active groups, compared with the group not having any moderate to vigorous activity, had substantial reductions in cardiovascular and all-cause mortality. Weekend warriors and those getting less than the recommended amount, compared with those getting no moderate to vigorous exercise, had close to a 30% reduction in all-cause mortality. Those meeting the guidelines and having at least three sessions per week had a 35% reduction in all-cause mortality. So there was not too much difference. All three active groups had about a 40% reduction in cardiovascular mortality compared with those who did not report any moderate to vigorous activity.

In a second report from the UK cohort, published in the British Journal of Sports Medicine,^[2] researchers asked participants about specific types of sports and moderate to vigorous activities that they engaged in. What they found was very interesting. A really wide range of sports and leisure-time activities were associated with substantial reductions in all-cause and cardiovascular mortality, including swimming, racket sports, and aerobics. Similar reductions in cardiovascular mortality were found with these types of activities.

She concludes: “It is a very good clinical public health message that some moderate to vigorous physical activity is substantially better than none, and that more is at least slightly better than some. We should encourage patients who are unable to meet the target, or who have to compress activity into one or two sessions per week or the weekend, to stick with it and be as active as they are able. We can expect that any activity will be better than none.”

“We need more research on physical activity and health, including randomized clinical trials of different types of activity, to further refine the activity guidelines. ”