Maryland: Exercise can’t hold off the effects of ageing, but it can improve an older person’s chances of keeping an independent lifestyle, researchers at the National Heart, Lung and Blood Institute.

In a treadmill test of different age groups, their aerobic capacity – the amount of oxygen consumed while exercising – declined at higher rates with each passing decade whether they exercised or not.

The researchers said the test revealed a greater decline that was known before said Dr. Jerome L. Fleg, a cardiologist who is lead author of the study and a medical officer at the National Heart, Lung and Blood Institute in Maryland.

However, he pointed out that those who exercise still end up ahead because their aerobic capacity was higher to begin with.

For the study published by the American Heart Association journal Circulation, researchers analyzed treadmill tests from 435 men and 375 women ages 21 to 87 taking part in the Baltimore Longitudinal Study of Aging.

The aerobic capacity was measured in the tests about every four years for a median of 7.9 years.

During their 20s and 30s, the volunteers’ aerobic capacity declined at a rate of 3 percent to 6 percent per decade. Those in their 70s and beyond faced a decline of more than 20 percent per decade, the researchers found. Those who exercised more strenuously had a higher aerobic capacity than those who didn’t.

Researchers said that one limitation of the study was that participants were healthy and able to walk on a treadmill, making it hard to make comparisons with less fit people in poorer health.