Swimming is one of the best aerobic |exercises|. It works out more than two-thirds of the body's total muscle mass and it places a vigorous demand on the |heart| and |lungs|. Swimming develops muscle strength and endurance and improves posture and flexibility. Stress on the bones and joints is minimized as the body is supported by the water. The best stroke to use for maximum aerobic benefit is the crawl, but the breast |stroke| and side |stroke| can be interchanged between laps if the glide phase is reduced. Build up slowly to a routine of swimming continuously for 30-40 minutes at least three days a week by starting with four laps of 25 yards each with a rest between each lap. Gradually add laps and decrease the rest periods.
