CHAPTER XIX
THE MUSCLES AND HEALTH
Making the Muscles Strong.—No persons use all of the five hundred muscles in the body every day. In slow walking only about twenty muscles are used, while in running more than four times that number are called into action. Muscles which are not used get lazy and weak.
Every time a muscle is made to act the blood vessels enlarge and bring to it more blood to supply food. The more food the muscle has the stronger it grows. The right arm is used more than the left in most persons. This makes it so much stronger that some boys can lift twenty-five pounds more with the right arm than they can with the left.
Using the Muscles keeps the Body Well.—All muscles must have more blood when they are used so that the heart is made to beat faster and stronger by exercise. In this way its valves and walls become able to do more work. Such a heart not only does its work better in a well person, but is able to keep pumping when the body is weakened by disease. Many persons die because the heart gets too weak to push the blood through the body.
In all the little spaces between the muscles and parts of other organs is some watery part of the blood containing much waste given off from the tissues. Moving the muscles presses on this watery waste in such a way as to move it along into the blood channels. It then can be cast out of the body by the lungs and other organs. One reason why we feel so good after exercise is because the poisonous waste has been taken away.
No one can remain well very long without taking exercise. Children as well as older persons should enjoy one or two hours of outdoor play every day.
Fig. 85 —Various ways of exercising the muscles to keep the body well.
How to exercise the Muscles.—Outdoor games give the best form of exercise. Tennis, baseball, cricket, rowing, and swimming are sports which bring nearly all the muscles into use. Every boy and girl should learn to swim. It is dangerous to go swimming alone or to swim in deep water. Cramp may seize the muscles at any time, so that the limbs cannot be moved. Hundreds of persons are drowned every year by venturing in deep water.
Taking care of the yard and garden and helping with other work about the home is one of the best ways of getting exercise and at the same time doing some good.
Special Kinds of Exercise.—A room with ropes, swings, and machines in it for exercise is called a gymnasium. Under the direction of a teacher the pupils can get quickly just the right kind of exercise to strengthen the weak parts of the body and keep every organ in health. The muscles oftenest neglected are those of the chest. Every one should keep his chest full and round by swinging the arms and practicing deep breathing every day.
Danger from too much Exercise.—Lately it has been learned that very violent exercise for more than a few minutes often injures the heart. The running of many races until you are all out of breath or much jumping of the rope is likely to strain the heart. It is always harmful to urge the body on until it is completely tired out.
Alcohol makes the Muscles Weak.—In the year 1903 two learned men in Switzerland spent much time to determine whether alcohol helped persons do more work. They tried more than two hundred experiments with men to whom they sometimes gave wine and sometimes food, and sometimes both were given together.
The results of these tests showed that when wine was given alone, the man's ability to do work was increased for a short time, but later he could not do so much work as when he had taken no wine. When the man took both food and wine, he could do only about nine tenths as much work as when he took food alone.
The most careful tests by other persons show that whisky will not help a man do more work, lift a heavier weight, or shoot straighter. In fact little or much whisky makes him less able to do any of these things.
Beer makes the Muscles Lazy.—Doctor Parkes of Netley secured two gangs of soldiers to do the same kind of work. He allowed the first gang to drink some beer, but the second gang were not allowed to have any. During the first hour the beer gang did the most work, but after that the temperance gang did far more work during the entire day. The next week beer was refused the first gang and given to the second. The beer helped the second gang do more work than the first one for nearly two hours, but after that they did much less than the first gang. This shows that men who wish to do their best work during the entire day should not use beer.
Tobacco and the Muscles.—Many experiments and studies have shown that the body cannot do its best work when even very small amounts of poison are taken day after day. The poison in tobacco is believed to weaken the muscles so much that no man on a football team in any of our large colleges or universities is allowed to smoke or chew during the season. Persons training for any contest where much strength is required do not use tobacco in any form.
Tobacco prevents Growth of the Muscles.—The moderate use of tobacco by men has but little effect on the muscles. It may cause them to tire a little more easily when doing very hard work. Tobacco poison does, however, show a marked effect on the muscles of the young.
Very careful measurements made at one of the large universities showed that the boys who did not smoke grew one tenth more in weight and one fourth more in height than those using tobacco regularly. This slow growth in tobacco users is partly due to the fact that tobacco makes the muscles in the walls of the blood vessels squeeze together so as to shut off some of the blood from the legs, arms, and other parts, so that they get too little food. Tobacco may also cause less food to be digested for the use of the body.