To Age Well, Walk
Rob C. Witzel for The New York Times
Regular exercise, including walking,
significantly reduces the chance that a frail older person will become
physically disabled, according to one of the largest and longest-running
studies of its kind to date.
The results, published on Tuesday in the journal JAMA, reinforce the necessity of frequent physical activity for our aging parents, grandparents and, of course, ourselves.
While everyone knows that exercise is a good
idea, whatever your age, the hard, scientific evidence about its
benefits in the old and infirm has been surprisingly limited.
“For the first time, we have directly shown
that exercise can effectively lessen or prevent the development of
physical disability in a population of extremely vulnerable elderly
people,” said Dr. Marco Pahor, the director of the Institute on Aging at
the University of Florida in Gainesville and the lead author of the
study.
Countless epidemiological studies have found a
strong correlation between physical activity in advanced age and a
longer, healthier life. But such studies can’t prove that exercise
improves older people’s health, only that healthy older people exercise.
Other small-scale, randomized experiments
have persuasively established a causal link between exercise and healthy
aging. But the scope of these experiments has generally been narrow,
showing, for instance, that older people can improve their muscle
strength with weight training or their endurance capacity with walking.
So, for this latest study, the Lifestyle
Interventions and Independence for Elders, or LIFE, trial, scientists at
eight universities and research centers around the country began
recruiting volunteers in 2010, using an unusual set of selection
criteria. Unlike many exercise studies, which tend to be filled with
people in relatively robust health who can easily exercise, this trial
used volunteers who were sedentary and infirm, and on the cusp of
frailty.
Ultimately, they recruited 1,635 sedentary
men and women aged 70 to 89 who scored below a nine on a 12-point scale
of physical functioning often used to assess older people. Almost half
scored an eight or lower, but all were able to walk on their own for 400
meters, or a quarter-mile, the researchers’ cutoff point for being
physically disabled.
Then the men and women were randomly assigned to either an exercise or an education group.
Those in the education assignment were asked
to visit the research center once a month or so to learn about
nutrition, health care and other topics related to aging.
The exercise group received information about
aging but also started a program of walking and light, lower-body
weight training with ankle weights, going to the research center twice a
week for supervised group walks on a track, with the walks growing
progressively longer. They were also asked to complete three or four
more exercise sessions at home, aiming for a total of 150 minutes of
walking and about three 10-minute sessions of weight-training exercises
each week.
Every six months, researchers checked the
physical functioning of all of the volunteers, with particular attention
to whether they could still walk 400 meters by themselves.
The experiment continued for an average of 2.6 years, which is far longer than most exercise studies.
By the end of that time, the exercising
volunteers were about 18 percent less likely to have experienced any
episode of physical disability during the experiment. They were also
about 28 percent less likely to have become persistently, possibly
permanently disabled, defined as being unable to walk those 400 meters
by themselves.
Most of the volunteers “tolerated the
exercise program very well,” Dr. Pahor said, but the results did raise
some flags. More volunteers in the exercise group wound up hospitalized
during the study than did the participants in the education group,
possibly because their vital signs were checked far more often, the
researchers say. The exercise regimen may also have “unmasked”
underlying medical conditions, Dr. Pahor said, although he does not feel
that the exercise itself led to hospital stays.
A subtler concern involves the surprisingly
small difference, in absolute terms, in the number of people who became
disabled in the two groups. About 35 percent of those in the education
group had a period of physical disability during the study. But so did
30 percent of those in the exercise group.
“At first glance, those results are
underwhelming,” said Dr. Lewis Lipsitz, a professor of medicine at
Harvard Medical School and director of the Institute for Aging Research
at Hebrew SeniorLife in Boston, who was not involved with the study.
“But then you have to look at the control group, which wasn’t really a
control group at all.” That’s because in many cases the participants in
the education group began to exercise, study data shows, although they
were not asked to do so.
“It wouldn’t have been ethical” to keep them
from exercise, Dr. Lipsitz continued. But if the scientists in the LIFE
study “had been able to use a control group of completely sedentary
older people with poor eating habits, the differences between the groups
would be much more pronounced,” he said.
Over all, Dr. Lipsitz said, “it’s an
important study because it focuses on an important outcome, which is the
prevention of physical disability.”
In the coming months, Dr. Pahor and his
colleagues plan to mine their database of results for additional
followup, including a cost-benefit analysis.
The exercise intervention cost about $1,800
per participant per year, Dr. Pahor said, including reimbursement for
travel to the research centers. But that figure is “considerably less”
than the cost of full-time nursing care after someone becomes physically
disabled, he said. He and his colleagues hope that the study prompts
Medicare to begin covering the costs of group exercise programs for
older people.
Dr. Pahor cautioned that the LIFE study is
not meant to prompt elderly people to begin solo, unsupervised exercise.
“Medical supervision is important,” he said. Talk with your doctor and
try to find an exercise group, he said, adding, “The social aspect is
important.”
Mildred Johnston, 82, a retired office worker
in Gainesville who volunteered for the LIFE trial, has kept up weekly
walks with two of the other volunteers she met during the study.
“Exercising has changed my whole aspect on
what aging means,” she said. “It’s not about how much help you need from
other people now. It’s more about what I can do for myself.” Besides,
she said, gossiping during her group walks “really keeps you engaged
with life.”
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