Babies, like kittens and puppies, are always moving. During every waking moment they twist and turn and throw their arms and legs about. This causes the blood to circulate freely and thus to carry food to the cells and waste materials away from the cells. In other words, activity helps the baby to nourish his body and to grow. It also helps him to get control of his muscles so that he can use them in many different ways later in life.
What activity does for the body.
Activity does at least five things for a person. First, it causes his body to grow. Second, it gives his body strength. Third, it gives his body skill. Fourth, it helps to keep his body in good working condition. Fifth, it tends to rest any parts of his body that may be fatigued. Activity causes more rapid oxidation in she cells. This means that the cells need more food and more oxygen. In order to supply the cells with the needed food and oxygen, the heart pumps the blood more rapidly, and more oxygen is taken into the lungs in breathing. The greater demand for food increases the appetite, and more food is taken into the body.: The added food and oxygen bring about a steady growth of cells. This explains why people who exercise regularly usually have very strong muscles.
As muscles become large, they also become strong. Have you ever seen a person bend his arm to show how large his muscles are? They bulge up beneath the skin and show that he has a great deal of strength. A black-smith’s arm is both large and strong.
Can you play a piano or a violin? If so, how did you learn? If not, why can you not play? A person who plays a piano or a violin does so as the result of many hours of practice. Activity trains the muscles to do things skillfully and gracefully. “Practice makes perfect” is a statement that has a great deal of meaning when it comes to training the muscles.
Activity helps to keep the body in good working order because it causes the blood to carry away waste materials more rapidly than usual. If the waste materials are removed promptly, the body is usually in a better condition than it is when they remain in the system. When they are not carried away as rapidly as they are formed, they act as poisons and keep the body from working well. The body becomes sluggish, and a person loses his ambition or feels tired or lazy.
When rest is mentioned, perhaps you think of sitting down or lying in bed. This, however, is not always the best way to rest. Of ten only a part of the body is really tired and it is not necessary to rest the whole body. Tired eyes, for example, may be rested while you are doing housework. A pupil who has been studying at a desk may rest by playing a game on the playground. A part of the body, such as the eyes, becomes tired because the waste materials are not carried away as rapidly as they should be. Using other parts of the body, as in doing housework, speeds up the circulation of the blood and carries some of the waste materials away. Thus the tired part becomes rested.
How the body gets exercise.
The body gets exercise through work and play. Work is any activity which a person carries on to secure food, shelter, or clothing. Play is any activity which a person carries on for enjoyment alone. Children get most of their exercise from play and adults, from work. Either kind of activity is good if it is carried on in the right way. Often, however, a person works or plays too hard or too long. Or he may use one part of his body more strenuously than he should. For these reasons, it is important that he plan his exercise into a program. If he is working or playing too hard, he should cut down something he is doing. If he is using one part of his body a great deal, he should rest it by taking other exercise. The best program for a person includes both work and play. This makes it possible for him to get different kinds of exercise according to his needs.