Page:Popular Science Monthly Volume 39.djvu/795

Rh guards were sometimes seen, from having run too long in the face of threatened suffocation, to fall in their places, struck with pulmonary congestion.

Exercises of force would also be as badly chosen for elderly men as exercises in speed, and for the same reason—that they fatigue the blood-vessels and the heart. Every muscular act that requires a considerable display of force inevitably provokes the physiological act called effort. A porter in lifting a heavy burden is obliged to make an effort, as does also the gymnast who executes an athletic movement with his apparatus. These are common facts of observation, and impressions which everybody has felt. If we put all possible energy into any movement, respiration stops at once, the muscles of the abdomen stretch, and the whole figure is stiffened, while the veins swell and mark salient sinuosities on the neck and forehead. I have explained the mechanism of effort in my book on the Physiology of Effort. It is enough to recollect here that it increases in excessive proportions the tension of the blood-vessels. Effort is translated, in fact, by a considerable pressure of the ribs on the lungs, and through this upon the heart and large vessels; under the influence of this pressure there is a reflow of the mass of the blood toward the smaller vessels and distention of their walls. When these vessels are tending to lose their elasticity, in consequence of the modification of structure observed in mature age, the violence to which the effort subjects them results in the aggravation of their inert state. In the same way the "fatigue" of a steel spring which has had too much to bear is increased. again after every violent pressure to which it is subjected. Nothing wears out a man who has reached maturity like great physical efforts, because nothing can more than effort aggravate the effects of that defect of nutrition which is called sclerosis.

In some cases arterial sclerosis is nothing but the gradual and slow consequence of the advance of age, but assumes a rapid pace that makes it a fearful malady. In such cases we can see young persons presenting the same physiological reactions against fatigue as the elderly man. One of the first symptoms of that acute aging of the arteries which is called arterial sclerosis is the dyspnœa of effort. All elderly men are, in different degrees, tainted with arterial degeneracy, and all ought to avoid excessive muscular effort if they would not wear out their arteries before the time—that is, would not grow old prematurely; for every man is "of the age of his arteries."

While the elderly man has less capacity for some forms of exercise than the younger adult, he has no less need than the