Using accelerometers to precisely measure physical activity, researchers have found that even very light exercise, well below the generally recommended levels, reduces mortality in older women.
The scientists had 6,382 women ages 63 to 99 wear an accelerometer for seven consecutive days, waking and sleeping, except when bathing or swimming. Using this data, they were able to precisely quantify levels of activity without having to rely on self-reports, which can be unreliable.
The study, in the Journal of the American Geriatrics Society, followed the women’s health for an average of 3.1 years, during which time there were 450 deaths.
They found that for each 30 minute a day increase in moderate-to-vigorous physical activity, there was a 39 percent decrease in all-cause mortality. But they also found that 30 minutes of even very light activity — doing light household chores, walking slowly over short distances — was tied to a 12 percent reduction in mortality.
“The results apply to all women, all races, regardless of weight and even for women over 80,” said the senior author, Andrea Z. LaCroix, a professor of epidemiology at the University of California, San Diego. “You do not have to be a marathon runner to benefit from physical activity. We hope that physical activity guidelines will recognize light activity as an evidence-based way to lower the risk for death.”
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