STANFORD,
Calif. (August, 2008) Regular running slows the effects of aging, according
to a new study from the Stanford University School of Medicine that has tracked
500 older runners for more than 20 years. Elderly runners have fewer disabilities,
a longer span of active life and are half as likely as aging nonrunners to die
early deaths, the research found.
"The
study has a very pro-exercise message," said James Fries, MD, an emeritus
professor of medicine at the medical school and the study's senior author. "If
you had to pick one thing to make people healthier as they age, it would be aerobic
exercise." The new findings appear in the Aug. 11 issue of the Archives of
Internal Medicine.
When
Fries and his team began this research in 1984, many scientists thought vigorous
exercise would do older folks more harm than good.
Some
feared the long-term effect of the then-new jogging craze would be floods of orthopedic
injuries, with older runners permanently hobbled by their exercise habit.
Fries
had a different hypothesis: he thought regular exercise would extend high-quality,
disability-free life. Keeping the body moving, he speculated, wouldn't necessarily
extend longevity, but it would compress the period at the end of life when people
couldn't carry out daily tasks on their own. That idea came to be known as "the
compression of morbidity theory."
Fries'
team began tracking 538 runners over age 50, comparing them to a similar group
of nonrunners. The subjects, now in their 70s and 80s, have answered yearly questionnaires
about their ability to perform everyday activities such as walking, dressing and
grooming, getting out of a chair and gripping objects.
The
researchers have used national death records to learn which participants died,
and why. Nineteen years into the study, 34 percent of the nonrunners had died,
compared to only 15 percent of the runners.
At
the beginning of the study, the runners ran an average of about four hours a week.
After 21 years, their running time declined to an average of 76 minutes per week,
but they were still seeing health benefits from running.
On
average both groups in the study became more disabled after 21 years of aging,
but for runners the onset of disability started later.
"Runners'
initial disability was 16 years later than nonrunners,'" Fries said. "By
and large, the runners have stayed healthy."
Not
only did running delay disability, but the gap between runners' and nonrunners'
abilities got bigger with time.
"We
did not expect this," Fries said, noting that the increasing gap between
the groups has been apparent for several years now. "The health benefits
of exercise are greater than we thought."
Fries
was surprised the gap between runners and nonrunners continues to widen even as
his subjects entered their ninth decade of life. The effect was probably due to
runners' greater lean body mass and healthier habits in general, he said. "We
don't think this effect can go on forever," Fries added. "We know that
deaths come one to a customer. Eventually we will have a 100 percent mortality
rate in both groups."
But
so far, the effect of running on delaying death has also been more dramatic than
the scientists expected. Not surprisingly, running has slowed cardiovascular deaths.
However, it has also been associated with fewer early deaths from cancer, neurological
disease, infections and other causes.
And
the dire injury predictions other scientists made for runners have fallen completely
flat. Fries and his colleagues published a companion paper in the August issue
of the American Journal of Preventive Medicine showing running was not associated
with greater rates of osteoarthritis in their elderly runners. Runners also do
not require more total knee replacements than nonrunners, Fries said.
"Running
straight ahead without pain is not harmful," he said, adding that running
seems safer for the joints than high-impact sports such as football, or unnatural
motions like standing en pointe in ballet.
"When
we first began, there was skepticism about our ideas," Fries said. "Now,
many other findings go in the same direction."
Fries,
69, takes his own advice on aging: he's an accomplished runner, mountaineer and
outdoor adventurer.
Hanging
on his office wall is a photo he jokingly describes as "me, running around
the world in two minutes." In the dazzling image of blue sky and white ice,
Fries makes a tiny lap around the North Pole.
Fries
collaborated with Stanford colleagues Eliza Chakravarty, MD, MS, an assistant
professor of medicine; Helen Hubert, PhD, a researcher now retired from Stanford,
and Vijaya Lingala, PhD, a research software developer.
The
research was supported by grants from the National Institute of Arthritis and
Musculoskeletal and Skin Diseases and by the National Institute on Aging.
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