People who engage weekly in some kind of moderate to vigorous physical activity have a longer life expectancy — no matter what their weight, a study published Tuesday in the journal PLoS Medicine has found.
Led by researchers at the National Cancer Institute, the study analyzed data from six large cohort studies involving more than 650,000 people, most of whom were over the age of 40. They found that those in the study who engaged in 2.5 hours of moderate-intensity aerobic exercise or 1.25 hours of vigorous exercise weekly (the minimum amount recommended by the World Health Organization’s 2010 guidelines) lived, on average, 3.4 years longer than those who didn’t exercise at all.
(In simplest terms, moderate aerobic activities are ones during which you can talk, like brisk walking, and vigorous activities are those during which you’d find it difficult to keep up a steady conversation, like running.)
Doubling the WHO recommendation increased life expectancy even further, to an average of 4.5 years. At that point, however, the benefits began to plateau.
Less activity still beneficial
Those whose weekly physical activity regime was half the WHO recommendation also extended their life expectancy, although by a more modest 1.8 years, on average.
These benefits were observed in men and women, among white and black participants, and, most interestingly, among people in the study who were obese.
For example, study participants who were of normal weight but physically inactive lived an average of 3.1 fewer years than their obese, but active, peers.
The study has several important limitations. Participants self-reported how much time they spent engaging in physical activity. Self-reports about exercising habits can be unreliable, particularly, some research has found, among individuals who are overweight and obese. In addition, this was an observational study, which means that other, unidentified, non-exercise factors in the participants’ lives might explain its findings. The authors did adjust for factors such as existing medical conditions (heart disease and cancer), but not for other potentially important factors, such as diet.
One more in growing body of research
Still, the study adds to a growing body of research that suggests people of all body weights benefit greatly from regular physical activity.
“Adding even low amounts of leisure time physical activity to one’s daily routine, such as 75 [minutes] of walking per week, may increase longevity,” write the study’s authors. “This finding may help convince currently inactive persons that a modest physical activity program is ‘worth it’ for health benefits, even if it may not result in weight control.”
The study can be downloaded for free at the PLoS Medicine website.