To age well, keep walking

By Gretchen Reynolds

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 May 27, 2014, in the Journal JAMA, support the necessity of frequent activity for our aging parents, grandparents, and, of course, ourselves.

Although everyone knows exercise is a good idea, whatever your age, the hard evidence about its benefits in the old and infirmed 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 of Aging at the University of Florida, Gainesville, and the lead author of the study.

Countless epidemiological studies have a strong tie between physical activity in advanced age and a longer, healthier life, But such studies can’t prove that exercise improver older peoples health, only that healthy older people exercise. Other small-scale, randomized experiments have persuasively established a causal link between exercise and healthy aging. But scope of these experiments generally is narrow, showing for instance, that older people can improve their muscle strength with weight training or their endurance capacity with walking.

So, for the latest study, the Lifestyle Interventions and Independence for Elders, or LIIE, trial, scientists at eight universities at eight universities and research centers around the country began recruiting volunteers in 2010, using an unusual set of selection criteria. Unlike in many studies, which tend to be filled with people in relatively robust health who can easily exercise, the scientists got 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 lower that a nine on a 12-point scale of physical functioning often used to assess older people. About half scored an eight or lower, but all were able to walk on their own for a quarter-mile, the research 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 unit 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 asked to complete three or four more exercise sessions at home, aiming for 150 minutes of walking and three 10 minute session of weight-training exercise each week. Every six months, researchers checked the functioning of all of the volunteers, with particular attention to whether they could still walk a quarter-mile.

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 an episode of physical disability. They also were about 28 percent likely to have become persistently, possibly permanently disabled, defined as being unable to walk a quarter-mile by themselves.

Most volunteers “tolerated the exercise program very well,” Pahor said, but results did raise some flags. More volunteers in the exercise group ended up hospitalized during the study than those 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, Pahor said, although he does not think the exercise itself led to hospital stays.