THE VALUE OF DEEP BREATHING
Deep breathing is undoubtedly extremely beneficial. Most of us, due largely to the fact that Nature leaves a considerable margin of safety, are able to carry on our ordinary activities without the requisite ventilation of the lungs, especially if we do not exercise. This, however, is injurious to the lungs, for it allows the blood to stagnate in them. Exercise is Nature's method of compelling ventilation in the lung area. Deep breathing may be used as a substitute, but the other beneficial effects of exercise are lost.
The skin and the various glands connected with it form a complex organism, the functions of which play a very important part in the work which the body has to do. The skin aids the lungs in their work of respiration; and, like the lungs, it throws off water and carbon dioxide and absorbs oxygen. The respiratory work of the skin, however, is only a minute fraction of that which the lungs do.
The skin is a heat regulator, and in this, its most important work, it is aided by the two million or more sweat-glands which are distributed over almost the entire surface of the body. The skin and the sweat-glands work together to keep the blood at an even temperature, either by giving off heat or in preventing this process in case the outside air is too cool. The body temperature, as a rule, is higher than that of the outside air, so that heat is generally being given off by the skin. We are perspiring constantly, but usually to such a slight extent that the fact is hardly noticeable. The amount of heat which is thrown off at any time is proportional to the amount of the tissue burned up by muscular action.