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Regular Exercise Can Reverse Drops in Age-Related Exercise Efficiency and Exercise Capacity
By Amy Norton
NEW YORK (Reuters Health) - Older adults may have to work harder than
young people to perform the same physical activity, but regular
exercise may close that age gap, research findings suggests.
In a study comparing sedentary adults in their 60s and 70s with those
in their 20s and 30s, researchers found that older men and women had to
use much more oxygen to walk at the same speed as their younger
counterparts.
But that was before they went through a six-month exercise program.
After taking up walking or jogging, biking and stretching, the senior
study participants reversed their loss of exercise "efficiency."
Exercise efficiency refers to how much energy the body expends to
perform a given activity. At the start of this study, older men and
women used 20 percent more oxygen to walk at the same speed as a
younger person, said Dr. Wayne C. Levy of the University of Washington
in Seattle, the study's senior author.
But six months of regular exercise -- 90 minutes, three days per week
-- improved older participants' exercise efficiency by 30 percent,
versus only 2 percent among their younger counterparts.
The findings are published in the current issue of the Journal of the American College of Cardiology.
It's well known that as people age, there is a decline in exercise
capacity -- how much work a person can do before becoming exhausted.
But the new findings suggest this is not just a product of the aging
cardiovascular system being less able to send oxygen to working
muscles. The older body also needs more oxygen to perform the same work
as a younger one -- that is, exercise efficiency declines.
But this decline appears to arise largely from inactivity, and may well be reversible.
The idea that exercise efficiency dips with age is a "relatively new
concept," Levy told Reuters Health. And though younger people in his
study were still better at pumping blood and oxygen to their muscles
after exercise training, it was only the older exercisers who showed
significant gains in exercise efficiency.
Their "disproportionately" greater improvement in this area, Levy and his colleagues write, is "new and unexpected."
It's not clear yet how intensely people need to exercise to hang on to
their efficiency as they age, according to Levy. But he said he
suspects that any activity done regularly, including walking, would
have benefits.
SOURCE: Journal of the American College of Cardiology, March 7, 2006.
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