Fit, Yet Fat? A Little Exercise May Add Years to Life

Middle-aged people who walk briskly for as little as 75 minutes per week may live 1.8 years longer, even if they are overweight. If they spend more time walking, running, swimming, cycling, or sweating in aerobics class, they may boost their life expectancy by 3.4 to 4.5 years.
Steven C. Moore, PhD, from the Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, Maryland, and coauthors report the findings of their pooled analysis online November 6 in PLoS Medicine.
More than 100 epidemiological studies have sought to clarify the role that physical fitness plays in lowering mortality risk. Dr. Moore and colleagues went a step further by looking at gains in life expectancy associated with varying durations of physical activity during leisure hours and at varying body mass index (BMI) measurements. The analysis comes as US physical activity levels have plummeted and waistlines have bulged.
The researchers pooled 6 prospective cohort studies, including 654,827 participants aged 21 to 90 years. With such a large sample size, the researchers were able to examine years of life gained after age 40 years, according to varying activity levels and with such added granularity as mortality hazard ratios by smoking status and race. Slightly more than half (56%) of the participants in the pooled analysis were women, 96.4% were white, 2.4% were black, and the median age was 61 years. The researchers measured the energy cost of such leisure time activities as sports and exercise through their metabolic equivalent (MET). Moderate- or vigorous-intensity activities, for example, rank 3 METs, which is about the same intensity as walking briskly. 

Walk Your Way to a Longer Life, Study Says