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.
ďFor 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,Ē 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.
For this latest study, the Lifestyle Interventions and Independence for Elders, or LIFE, trial, scientists at eight universities and research centres 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 researchersí 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 centre once a month or so to learn about nutrition, health care and other topics related to ageing.
The exercise group received information about ageing but also started a programme 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 if they could still