CHAPTER XIII
PERSONAL HYGIENE
Whatever the conditions under which one lives, or whatever his abstract knowledge of foods and sanitation, the health of the individual resolves itself at last into a question of his personal habits; and some of these personal questions must be considered in a book of this character.
Exercise.
One of the commonly accepted facts of hygiene is that, for the best development and for the perfect health of the human body, a certain amount of exercise should be taken by each part of the body. This is true not only for the larger muscles, such as those of the arms and legs, but also for the muscles of those internal organs less frequently considered. Experiments have been made by tying up some part of the body, such as the forearm, with the result that, in the course of a few weeks, its functions have been so lessened that its usefulness is temporarily at an end. But the general effect of exercise on the body, aside from the beneficial results on the particular muscles engaged, is to promote the building up of new lung tissue. Oxygen is received from the lungs through the blood and is carried to the different parts of the body, where it serves the useful purpose of carrying off the waste products of the different organs. If the lung action is inadequate, if deep breathing in fresh air is not practiced, or if, through laziness, no exercise is taken, then the amount of oxygen supplied will be deficient and the body will be loaded up with the toxic products resulting from decomposition. The exact effect of exercise upon the lung action may be seen from the fact that under ordinary circumstances a man breathes about 480 cubic inches of air per minute. If he is walking at the rate of 4 miles an hour, he inhales air at 5 times this rate, and if he is walking at the rate of 6 miles an hour, inspiration increases to seven times this rate, or 3360 cubic inches of air passes through his lungs per minute instead of 480, as when at rest.
Of course, it is assumed that in the country a person has no lack of exercise, and that of all men the farmer is in least need of exercise. But, as a matter of fact, the exercise which he gets is irregular and confined to certain sets of muscles, rather than to the development of the whole body. Agility, for instance, quickness of action and immediate control of the muscles, is far less common in the country than is supposed, although there is probably no lack in the actual power of the muscles. It is common observation that among farmers an erect carriage is less frequently seen than an awkward, shuffling gait. The fact is, that exercise, to be beneficial, should affect not one set of muscles, but all the muscles of the body, because the continuous exercise of one set, while leading first to growth, results later in demolition and waste. When, however all the muscles of the body are exercised, there is no demolition or waste, but a healthy growth throughout. Regular exercise is beneficial, not merely to the muscles involved, but also to the other organs of the body. Exercise sharpens the appetite, makes digestion more perfect, and increases the absorptive power of the intestinal membranes; conversely, lack of exercise, which is found in the country in the winter, lessens both the digestive power and the appetite.
Clothing.
Little need be said on this subject, since the amount of clothing needed varies so greatly with the vitality of the individual. It has already been pointed out that in rural communities the death-rate from pneumonia, bronchitis, and similar respiratory troubles is much higher than in urban communities, and it is quite possible that deficient or unsuitable clothing is practically responsible for this.