“You couldn’t be sixty. I don’t believe it.” This astonished pronouncement came from a woman talking to another while waiting for a yoga class to begin. I was nearby and was astonished myself. The sixty year-old looked about 40; she was trim and muscular and I knew from previous classes that she could stretch herself into yoga positions far too complicated for the rest of us. “My birthday is next week, “ the sixty year-old who looked forty replied. “But you know I have been exercising all my life and I really think it keeps my body from looking its age.” As the teacher entered the room and we sat on our mats, I thought that if anyone needed convincing that exercise would make them look younger they had only to look at her. The public is constantly exhorted to get off the couch and into the gym or at least into walking shoes and out the door. The benefit of burning off calories so we are less likely to gain weight, and more apt to lose it, is indisputable. Exercise helps us sleep, improves our cardiovascular health and recently has been shown to improve our mental health and cognitive abilities as well. Yet many who hear these wonderful things about exercise still resist committing themselves to doing it. Maybe the message ought to be changed to extolling the effects of exercise on keeping us looking younger.American women spend enormous amounts of money on skin care products to fight wrinkles, sagging chins, and puffiness under the eyes. Some of these products promise to firm skin, not only on the face but on the body as well. What the advertisements for these firming products don’t say is that building muscle under the skin will firm it quite nicely. One has only to look at our First Lady to see the effects of working out the upper body and arms on skin tone and firmness.Recently I had lunch with a friend who is over 70 but looks at least l0 years younger. We talked about how old our grandmothers and even our mothers looked when they were in their sixties compared to women in their sixties and seventies today.“ I really think it is the exercise that does it,” she said. “I lift weights three times a week and do cardiovascular exercise every day. Look,” she said pointing to her underarms,” no wings.”Physical activity and exercises that build muscle not only keep the body from sagging in the wrong places (are there are any right ones?) but also give the owner of the exercised body the ability to walk vigorously, stand and sit with good posture, maintain balance even if slipping on ice or stumbling on an uneven curb or sidewalk and look good in clothes. Obviously, there are limits to what exercise can do: No workout routine will turn a fifty year-old body into one resembling that of a seventeen year-old in a bikini. But it will turn back the clock on one’s physical appearance, especially if strengthening the muscles, improving flexibility and boosting cardiovascular output are all part of the routine. It is not sufficient to concentrate on only one of these areas. For example, as important as vigorous walking is, moving the lower part of the body will do nothing to strengthen the upper back, chest and arms. And strength training will not have any impact on flexibility and balance unless stretching and balancing routines are inserted into the strength-training program.Depending on a gym to carry out an exercise routine may be difficult because of cost, lack of time, or accessibility. Fortunately, there are many DVDs with all the routines necessary to have a balanced activity program. The summer is coming and swimming as exercise answers the need to work out the upper body and also do cardiovascular activity. (And hopping on one foot to get water out of the ear is a pretty good way to practice balancing.) Local high schools and community centers have exercise programs for all levels and daytime as well as evening hours.Getting started is hard, especially if exercise is low on the list of things to do each day. But if you should be at the cosmetic department wondering about the anti-aging miracles some cream may perform, or deciding whether you can risk wearing short sleeves, think of exercise. The results will show up faster than those promised by the cream and if you start now, you might be able to wear those short sleeves by summer.