By Janice Lloyd, USA TODAY
Want to know how long you or your aging parents will live? One simple indicator of well-being and longevity among older people is their walking speed, new research shows.
In an analysis of nine studies involving more than 34,000 people age 65 and older, faster walking speeds were associated with living longer: Predicted years of remaining life for each age and both sexes increased as gait-speed increased, with the most significant gains after age 75.
In addition, researchers found that predicting survival based on gait speed was as accurate as predictions based on age, sex, chronic conditions, smoking history, blood pressure, body mass index and hospitalization.
"My hope is that we begin to think about ways to reflect the health and function of older people that goes beyond diseases," says lead researcher Stephanie Studenski, a geriatric physician at the University of Pittsburgh, whose analysis appears today in the Journal of American Medical Association. "Functional status (walking speed) is an important reflection of health."
Walking is a reliable tool to measure well-being, Studenski says, because it requires body support, timing and power, and places demands on the brain, spinal cord, muscles and joints, heart and lungs. Slowing down is associated with getting older. By age 80, gait speed is approximately 10% to 20% slower than in young adults, she says.
The findings can provide doctors with an inexpensive, safe and simple way of measuring performance that can help identify health problems, she says, and in many cases lead to treatments that can improve well-being, ward off disabilities and help the elderly maintain independence.
"I think it's a very useful tool, and some physicians already use it," says Evan Hadley, associate director of geriatrics at the National Institute on Aging. "It's far from universal, though. This study does show walking speed is a very strong predictor of survival."
In the study, gait speed was calculated using distance in meters and seconds. All subjects were instructed to walk at their usual pace and from a standing start. Average rate of speed was 3 feet per second (about 2 miles an hour).
During the 14-year course of the study, there were 17,528 deaths. Those who walked slower than 2 feet per second (about 1.36 miles an hour) had an increased risk of dying. Those who walked 3.3 feet per second (about 2.25 miles per hour) or faster survived longer than would be expected by age or sex alone.
Outside of the study presented in JAMA, Studenski measured the walking gait of Edward Gerjuoy, 92, a professor emeritus of physics at Pitt, to be 4.26 feet per second or about 3 miles an hour. She says his probability of living 10 more years (to age 102) is about 40%, and his median life expectancy is about seven years.
He attributes his longevity to luck. He has always tried to maintain a healthy weight, he says, but he didn't start going to a gym to work out until he was 80, and he was never athletic. Now his "workouts" involve climbing the stairs daily at the university.
"My office is on the third floor," he says. "I walk from the parking lot to my office and down to the second floor several times a day because the printer is there."
He plans to keep climbing the stairs and is encouraged by Studenski's findings.
Studenski says the researchers are not advising people to walk faster — that would be unsafe — and some slow walkers do live a long time. "A very important point is that your body chooses a walking speed that is best for you," she says.
"If a person is walking slowly, I might be able to identify what might be contributing to their problem and, in doing so, find ways to help them function better."
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