"Older subjects are less efficient than younger subjects. This inefficiency can be reversed by aerobic exercise training," said Wayne C. Levy, M.D., F.A.C.C. from the University of Washington in Seattle.
"It is well known that aging is associated with reduced exercise capacity. What is less appreciated is that older subjects have an additional impairment in exercise capacity due to exercise inefficiency. For example, the older subjects used about 20 percent more oxygen to walk at 3.5 miles an hour than the younger subjects. Thus, the older subject walking at 3 miles per hour and the younger subject walking at 3.5 miles per hour used the same amount of oxygen. With training, this disparity with aging was abolished," he added.
The researchers from the University of Washington and the Veterans Affairs Puget Sound Health Care System in Seattle, including lead author J. Susie Woo, M.D., compared participants in their 20s to early 30s (15 women and 12 men) to those in their mid-60s to late 70s (16 women and 18 men).
Before training, the younger participants had a much higher exercise capacity, as shown by a peak oxygen consumption (delivery of oxygen to exercising muscle) that was 42 percent higher. Younger participants also didn't have to work as hard and were 8 percent more efficient than the older participants.
Then all the participants were entered into a supervised aerobic exercise program. Three times per week they walked or jogged, bicycled, and stretched, doing each for 30 minutes during a 90-minute workout session.