Exercise is good for you! In the context of physical fitness, “exercise” refers to any activity involving a fairly high degree of physical movement that makes you breathless and sweaty if you do it vigorously. Gardening or walking can be as much exercise as a game of tennis or an hour of bicycling, provided it is done vigorously enough.
There is a sound medical reason why physical activity is good for you. Any work that muscles must do increases their need for oxygen. During physical exercise, you must breathe more deeply to get more oxygen into your lungs, and your heart (which is itself almost all muscle) must beat harder and faster to pump blood to the muscles. Heart disease accounts for almost a third of all deaths and a high proportion of serious illness in North America. So an efficient, resilient heart, not to mention strong lungs, means you are less likely to have major health problems compared to a non-exercising contemporary. One medical study has shown that middle-aged people with desk jobs who do not exercise are twice as susceptible to heart attacks as those people who exercise regularly.
Up to a reasonable point, the more you work your muscles and the larger the number of muscles and joints you use, the greater the physical gain. The most beneficial kind of exercise is known as “dynamic”. Dynamic exercise such as swimming or jogging strengthens the heart, lungs and body muscles when it makes you breathless and sweaty. It also keeps joints supple, and your mind and body active. The alternative, “static” exercise such as weight lifting, can build specific muscles to excessive degrees, does less to improve your heart and lungs and may not raise your general level of fitness.
Lack of exercise can contribute to the development of various disorders. Anyone who has had an illness or injury and was forced to lie in bed for a time knows how weak their muscles become. The same disuse also affects the bones and can affect the heart and lungs. Be careful, exercise can damage muscles, ligaments or joints. If you exercise regularly, however, the risk of injury is less than if you exercise after months of little or no exercise.