Personal hygiene and physical training for women

by Anna M. Galbraith

The Toxins of Fatigue.—By speeding the machinery to the utmost, a strain is placed on nerves and muscles, and they are kept keyed up to the greatest possible tension. There is a natural pace that one can keep up; force the pace, and weariness results. A man can go for hours at the rate of five miles an hour; he can run at the rate of six miles an hour for quite a long while; but if he tries to run eight miles an hour, he will drop out very soon. The powers of endurance must be gradually developed, but no machine should ever be run at its utmost speed.

By undue pressure, at any period of life, it is possible to use up energy that ought to have been spread out over long periods; and this is emphatically the case during adolescence; too heavy a drain is made on futurity, which means a serious breakdown, or, at least, premature old age.

It has long been assumed that during the activity of muscles substances were produced which exerted a poisonous influence upon the muscle tissues. Exactly what these substances were was not known, but it was supposed that they were definite products of metabolism or tissue waste. It is a well-known phenomenon, observed during the training of athletes and soldiers, that prolonged and disciplined exercise makes it possible for individuals to support easily an amount of work which would prove exhausting or even fatal to the untrained. Increased work, under any circumstances, means increased metabolism, and consequently a more rapid accumulation of its products.

A German investigator, Dr. Weichardt, has shown that if guinea-pigs were put upon a miniature treadmill and forced to run it until they dropped dead from exhaustion, a highly poisonous liquid could be pressed from their muscles, and that the injection of this liquid or extract into the veins of healthy guinea-pigs produced, when administered in small doses, rapid fatigue; whereas, larger doses caused death, accompanied by all the symptoms observed in the original animal during the process of mechanical tiring.

On the other hand, liquid taken from unworked guinea-pigs had no such effect. Further, that if these little animals were put upon a treadmill and worked to just short of exhaustion, and then were given time to recuperate, as we say, the liquid or extract from their muscles had no such effect: it was quite harmless.

From the results of these carefully carried out scientific investigations, Weichardt has come to the conclusion that fatigue is due to a definite toxin, analogous to that of diphtheria and tetanus, and he believes that the explanation of the phenomena of training lies in the fact that in the body of the athlete there must be a specific “antibody,” which neutralizes the “fatigue toxin” as soon as it is formed.

In the animals undergoing these experiments of extreme fatigue there was a fall of temperature. A practical use of this fact could be made for the individual, by noting the fact that a subnormal temperature was a grave danger-signal.

Other observers concede that fatigue is due to chemical substances, produced in the body as the result of brain and muscle activity, and find that these toxins produce a depressing effect, especially on the muscular system, and that the sensation of fatigue is in large part the manifestation of this depression. The action of toxins is not confined to the tissues in which they arise; excessive activity of one tissue can cause fatigue of others. The facts of acid intoxication are noticed as analogous to fatigue phenomena, so far as the latter are due to toxic substances. As antidotes, only rest and sleep can be relied upon.

Observations in the electric experiments on nerve-cells have shown a remarkable shrinking of the nerve-cells, and especially of their nuclei. After five hours’ continuous work, the cell nucleus was only half its normal size, and twenty-four hours of rest was necessary in order to restore it to its normal size, but half that amount of work does not require half that amount of time for its recovery.

The mental symptoms of normal fatigue are loss of memory; the sense of perception is less acute; the association centers act less spontaneously and therefore slower; the vocabulary diminishes; the emotional tone is lowered; the attention is unstable and flickering. All these are marked symptoms that the individual is far below her best. All kinds of perceptions are more acute in the morning.