For several years now, health experts have recommended walking and other moderate-intensity activities as exercise options for those who can’t — or won’t — exercise more vigorously. But most people have assumed that more strenuous exercise would produce better cardiovascular and overall fitness. Not so, say two studies in the January 27 Journal of the American Medical Association.

In the first study, 190 previously sedentary men and women participated in a two-year exercise program. Researchers assigned almost half to attend supervised, vigorous exercise classes at a fitness center, gradually working up to five classes a week. The others spent 30 minutes on most days of the week pursuing a more moderate-intensity activity that suited their lifestyle, such as walking. All 190 participants also attended classes designed to motivate them to exercise. After two years, both groups were burning calories at a similar rate and showed comparable improvements in aerobic fitness, blood pressure, and body fat (though no one lost much weight).

In the second study, 33 obese women spent a year either attending three step-aerobics classes a week or doing less strenuous exercise on their own for 30 minutes most days of the week.

All of the women attended several classes aimed at modifying behavior to achieve weight loss and followed a low-calorie diet. At the end, both groups had similar weight loss and improvements in aerobic fitness. Although they all gained some weight back after an initial loss, those who exercised most often — whether doing light or more vigorous exercise — were most successful in keeping the weight off.

These studies make clear that the amount of time you spend exercising counts more than how hard you exercise. The key is to choose whatever activity you’ll be motivated to do most often — and will continue to do year after year. Besides walking, moderate-intensity activities include gardening, leisurely biking, golfing, and even taking the stairs instead of the elevator at work. As always, check with your doctor before starting any new exercise routine.