A retrospective study shows that walking briskly, cycling or swimming for 15 minutes a day can help older people live longer. The study suggests that even a little bit of exercise can benefit older adults. The study showed that just 15 minutes of moderate to vigorous physical activity reduced mortality by 22 percent compared to patients who did no activity at all. Subjects who exercised moderately for 75 minutes a week or vigorously for 150 minutes a week had a 28 percent lower risk of death. Dr. David Hupin of CHU Saint-Etienne, France, and colleagues analyzed a study of 122,417 older adults, 60-101 years old, from the United States, Taiwan, and Australia. The study assessed participants’ physical activity levels, risk of all-cause mortality during 10 years of follow-up. They also collected participants’ self-reported health status, physical or mental illness, weight, cholesterol and other details. The researchers used metabolic equivalents (MET) to detect energy expenditure or “dose” of exercise. Resting energy expenditure was assumed to be 1 MET; vigorous exercise was 6 METs or more. Brisk walking was considered moderate exercise (3-5.9 METs). The low exercise group was 1-499 MET-minutes, the moderate exercise group was 500-999 MET-minutes, and the maximal exercise group was above 1000 MET-minutes. The results found that the group that exercised the most (>1000MET-minutes/week) had a 35% lower risk of death. The study also found a curvilinear relationship between physical activity and all-cause mortality, with the many benefits appearing to be a lower risk of cardiovascular disease death. The association between activity and lower cancer mortality was not as strong, but the risk reduction was still significant.