There's a growing agreement among exercise researchers that the vigorous activities of most health clubs are not the best path to overall health.

Walking is better. At a vigorous pace of 3 to 4 mph, walking for half an hour five or six times a week could be the perfect exercise. It is one of the safest activities, and it's easy on your body.

Doctors at Harvard's Brigham and Women's Hospital say that if everyone were to walk briskly for 30 minutes a day, we could cut the incidence of many chronic diseases by 30 or 40 percent. What's more, new studies suggest that walking briskly in 10-minute intervals provides just about the same benefits as walking for 30 minutes does.

It's almost a magic bullet. Walking helps to prevent heart disease, stroke, diabetes, osteoporosis, arthritis, and depression, among its better known benefits.

And it makes you look better by aiding in weight control and weight loss. The older you get, the harder it is to maintain your weight by restricting calories. But vigorously walking for half an hour burns 200 calories and makes your body burn calories faster for the rest of the day!

Exercise, even walking at an easy pace, appears to protect the aging brain from erosion of thinking ability and Alzheimer's disease.

Doctors at the Harvard School of Public Health found that older people who were physically active, including those who walked at a leisurely pace up to three hours a week, performed much better on tests of memory and thinking ability than those who were inactive. They had a 20 percent reduced risk of doing poorly on tests of cognitive ability. There were more than 18,000 participants in the study.