Leisure-Time Physical Activity Extends Life Expectancy As Much As 4.5 Years 2012

Leisure-time physical activity is associated with longer life expectancy, even at relatively low levels of activity and regardless of body weight, according to a study by a team of researchers led by the National Cancer Institute (NCI), part of the National Institutes of Health.

Leisure-Time Physical Activity Extends Life Expectancy As Much As 4.5 Years 2012

The study, which found that people who engaged in leisure-time physical activity had life expectancy gains of as much as 4.5 years, appeared this week in PLoS Medicine.

In order to determine the number of years of life gained from leisure-time physical activity in adulthood, which translates directly to an increase in life expectancy, researchers examined data on more than 650,000 adults. These people, mostly aged 40 and older, took part in one of six population-based studies that were designed to evaluate various aspects of cancer risk.

Most governments recommend that adults ages 18 to 64 should engage in regular aerobic physical activity for 2.5 hours at moderate intensity – or 1.25 hours at vigorous intensity – each week. Moderate activities are those during which a person could talk but not sing. Vigorous activities are those during which a person could say only a few words without stopping for breath.

After accounting for other factors that could affect life expectancy, the researchers found that life expectancy was 3.4 years longer for people who got the recommended level of physical activity. People who reported leisure-time physical activity at twice the recommended level gained 4.2 years of life. In general, more physical activity corresponded to longer life expectancy.

The researchers even saw benefit at low levels of activity. For example, people who said they got half the recommended amount of exercise still added 1.8 years to their life. Physical activity was categorised by "metabolic equivalent hours per week" (MET-h/wk). Brisk walking for up to 75 min/week, for example, was equivalent to 0.1–3.74 MET-h/wk.

"Our findings highlight the important contribution that leisure-time physical activity in adulthood can make to longevity," said lead author of the study Steven Moore, Ph.D. "Regular exercise extended the lives in every group that we examined in our study – normal weight, overweight, or obese."

The researchers found that the association between physical activity and life expectancy was similar between men and women, and blacks gained more years of life expectancy than whites. The relationship between life expectancy and physical activity was stronger among those with a history of cancer or heart disease than among people with no history of cancer or heart disease.

The researchers also examined how life expectancy changed with the combination of both activity and obesity. Obesity was associated with a shorter life expectancy, but physical activity helped to mitigate some of the harm. People who were obese and inactive had a life expectancy that was between five to seven years shorter (depending on their level of obesity) than people who were normal weight and moderately active.

Physical activity has been shown to help maintain a healthy body weight, maintain healthy bones, muscles and joints, promote psychological well-being, and reduce the risk of certain diseases, including some cancers.

"We must not underestimate how important physical activity is for health – even modest amounts can add years to our life," said I-Min Lee, a senior author on the study.