Exercise -- even if you don't start until your 40s -- can cut your risk of heart disease by up to 90 percent.

That's the word from German researchers who looked back at data gathered in a comparison of 312 people with heart disease and 479 age-matched, healthy blood donors.

Better Late Than Never for Exercise

Those who exercised very little, if at all, were most likely to have heart disease. That finding did not surprise University of Heidelberg researcher Dietrich Rothenbacher, MD, MPH, and colleagues. Nor were they surprised to find that those who exercised a lot, from their 20s through their 40s, had a 62 percent lower risk of heart disease than the lifelong couch potatoes.

But they were surprised by their findings about those who got little exercise until their 40s. By starting to exercise, these people were able to cut their risk of heart disease by more than half.

Most of this reduced risk, however, was among those who went from getting very little activity to being very active. This very-active-over-40 group had 90% less heart disease than those who remained inactive.

"Changing from a sedentary to an active physical activity pattern, even if initiated at older age, may result in a strong reduction of coronary heart disease risk," Rothenbacher and colleagues conclude.

The study appears in the current issue of the journal Heart. In an editorial accompanying the study, S. Goya Wannamethee, PhD, of London's Royal Free and University College, notes that the new findings show the benefit of exercise -- even for very late bloomers.

The German researchers found the most benefit for people who began rather strenuous exercise regimens. But Wannamethee notes that any exercise -- even light exercise -- makes a difference.

"The level of exercise required to achieve benefit may be dependent on age, sex, and the level of fitness," he writes. "Among those at the lower end of the spectrum of physical activity -- that is, more sedentary or less fit people such as women or older men -- moderate intensity activity is sufficient. In those more active or physically fit or younger, vigorous activity may be needed to provide additional benefit."

By Daniel J. DeNoon, reviewed by Louise Chang, MD