Our muscles allow us to move. They pull on bones and move our limbs. If the muscles do not have enough pulling to do they become smaller. This is called wasting. Sometimes muscle wasting cannot be helped. If a person has an injury to a leg, the muscles in the leg may not be used for some weeks. In that time the muscles will waste. When the leg has recovered from the injury it has to be exercised to build up the muscles again.

If a person does not take any exercise all the muscles will waste and become weaker. This makes it difficult for them to start exercising because they tire easily and soon give up. The way for them to take up exercise is to begin by doing small amounts of exercise such as walking to the shops instead of riding in a car or bus. After that they should gradually build up their exercise until they can walk briskly for about twenty minutes three times a week. People who have not done any exercise for a long time should see their doctor before they start.

Exercise not only strengthens the body muscles but it also strengthens the heart muscle and makes the heart beat more efficiently. Exercise also helps the lungs. Most of the time we only breathe with the upper part of the lungs. This means that dust and dirt that we breathe in can settle in the lower parts. These particles irritate the lining of the lung and may cause infection. When we exercise all the parts of the lungs are used and the dust and dirt are cleared out when we breathe deeply.

Young people tend to exercise more than older people. They play sports and dance to music. This not only helps the muscles, heart and lungs stay healthy but it also helps the bones to form properly. As people get older they tend to exercise less and this also creates another problem because although they use less energy they still keep eating the same amount of food. The energy in the food that they do not use is stored as fat and makes the body overweight . This puts extra strain on a heart that is already becoming weaker because of a lack of exercise and may result in a heart attack. However all this may be avoided if older people exercise and they will feel much better too.