Since we are endowed with the energy requisite for such efficient work, the obvious question is, why do we not more frequently use it? The answer is to be found in the fact that we have formed the habit of giving up before we create conditions of high efficiency. You will note that the conditions require long-continued exertion and resolute persistence. This is difficult, and we indulgently succumb to the first symptoms of fatigue, before we have more than scratched the surface of our real potentialities.
Because of the prominent place occupied by fatigue in thus being responsible for our diminished output, we shall briefly consider its place in study. Everyone who has studied will agree that fatigue is an almost invariable attendant of continuous mental exertion. We shall lay down the proposition at the start, however, that the awareness of fatigue is not the same as the objective fatigue in the organs of the body. Fatigue should be regarded as a twofold thing—a state of mind, designated its subjective aspect, and a condition of various parts of the body, designated its objective aspect. The former is observable by introspection, the latter by analysis of bodily secretions and by measurement of the diminution of work, entirely without reference to the way the mind regards the work. Fatigue subjectively, or fatigue as we feel it, is not at all the same as fatigue as manifested in the body. If we were to make two curves, the one showing the advancement of the feeling of fatigue, and the other showing the advancement of impotence on the part of the bodily processes, the two curves would not at all coincide. Stated another way, fatigue is a complex thing, a product of ideas, feelings and sensations, and sometimes the ideas overbalance the sensations and we think we are more tired then we are objectively. It is this fact that accounts for our too rapid giving up when we are engaged in hard work.
A psychological analysis of the subjective side of fatigue will make its true nature more apparent. Probably the first thing we find in the mind when fatigued is a large mass of sensations. They are referred to various parts of the body, mostly the part where muscular activity has been most violent and prolonged. Not all of the sensations, however, are intense enough to be localizable, some being so vague that we merely say we are "tired all over." These vague sensations are often overlooked; nevertheless, as will be shown later, they may be exceedingly important.
But sensations are not the only contents of the mind at time of fatigue. Feelings are present also, usually of a very unpleasant kind. They are related partly to the sensations mentioned above, which are essentially painful, and they are feelings of boredom and ennui. We have yet to examine the ideas in mind and their behavior at time of fatigue. They come sluggishly, associations being made slowly and inaccurately, and we make many mistakes. But constriction of ideas is not the sole effect of fatigue. At such a time there are usually other ideas in the mind not relevant to the fatiguing task of the moment, and exceedingly distracting. Often they are so insistent in forcing themselves upon our attention that we throw up the work without further effort. It is practically certain that much of our fatigue is due, not to real weariness and inability to work, but to the presence of ideas that appear so attractive in contrast with the work in hand that we say we are tired of the latter. What we really mean is that we would rather do something else. These obtruding ideas are often introduced into our minds by other people who tell us that we have worked long enough and ought to come and play, and though we may not have felt tired up to this point, still the suggestion is so strong that we immediately begin to feel tired. Various social situations can arouse the same suggestion. For example, as the clock nears quitting time, we feel that we ought to be tired, so we allow ourselves to think we are.
Let us now examine the bodily conditions to see what fatigue is objectively. "Physiologically it has been demonstrated that fatigue is accompanied by three sorts of changes. First, poisons accumulate in the blood and affect the action of the nervous system, as has been shown by direct analysis. Mosso … selected two dogs as nearly alike as possible. One he kept tied all day; the other, he exercised until by night it was thoroughly tired. Then he transfused the blood of the tired animal into the veins of the rested one and produced in him all the signs of fatigue that were shown by the other. There can be no doubt that the waste products of the body accumulate in the blood and interfere with the action of the nerve cells and muscles. It is probable that these accumulations come as a result of mental as well as of physical work.
"A second change in fatigue has been found in the cell body of the neurone. Hodge showed that the size of the nucleus of the cell in the spinal cord of a bee diminished nearly 75 per cent, as a result of the day's activity, and that the nucleus became much less solid. A third change that has been demonstrated as a result of muscular work is the accumulation of waste products in the muscle tissue. Fatigued muscles contain considerable percentages of these products. That they are important factors in the fatigue process has been shown by washing them from a fatigued muscle. As a result the muscle gains new capacity for work. The experiments are performed on the muscles of a frog that have been cut from the body and fatigued by electrical stimulation. When they will no longer respond, their sensitivity may be renewed by washing them in dilute alcohol or in a weak salt solution that will dissolve the products of fatigue. It is probable that these products stimulate the sense-organs in the muscles and thus give some of the sensations of fatigue. Of these physical effects of fatigue, the accumulation of waste products in the blood and the effects upon the nerve cells are probably common both to mental and physical fatigue. The effect upon the muscles plays a part in mental fatigue only so far as all mental work involves some muscular activity."
By this time you must be convinced that the subject of fatigue is exceedingly complicated; that its effects are manifested differently in mind and body. In relieving fatigue the first step to be taken is to rest properly. Man cannot work incessantly; he must rest sometimes, and it is just as important to know how to rest efficiently as to know how to work efficiently. By this is not meant that one should rest as soon as fatigue begins to be felt. Quite the reverse. Keep on working all the harder if you wish the second-wind to appear. Perhaps two hours will exhaust your first supply of energy and will leave you greatly fatigued. Do not give up at this time, however. Push yourself farther in order to uncover the second layer of energy. Before entering upon this, however, it will be possible to secure some advantage by resting for about fifteen minutes. Do not rest longer than this, or you may lose the momentum already secured and your two hours will have gone for naught. If one indulges in too long a rest, the energy seems to run down and more effort is required to work it up again than was originally expended. It is also important to observe the proper mental conditions during rest. Do not spend the fifteen minutes in getting interested in some other object; for that will leave distracting ideas in the mind which will persist when you resume work. Make the rest a time of physical and mental relief. Move cramped muscles, rest your eyes and let your thoughts idly wander; then come back to work in ten or fifteen minutes and you will be amazed at the refreshed feeling with which you do your work and at the accession of new energy that will come to you. Keep on at this new plane and your work will take on all the attributes of the second-wind level of efficiency.
Besides planning intelligent rests, you may also adjust yourself to fatigue by arranging your daily program so as to do your hardest work when you are fresh, and your easiest when your efficiency is low. In other words, you are a human dynamo, and should adjust yourself to the different loads you carry. When carrying a heavy load, employ your best energies, but when carrying only a light load, exert a proportionate amount of energy. Every student has tasks of a routine nature which do not require a high degree of energy, such as copying material. Plan to perform such work when your stock of energy is lowest.
One of the best ways to insure the attainment of a higher plane of mental efficiency is to assume an attitude of interestedness. This is an emotional state and we have seen that emotion calls forth great energy.
A final aid in promoting increase of energy is that gained through stimulating ideas. Other things being equal, the student who is animated by a stimulating idea works more diligently and effectively than one without. The idea may be a lofty professional ideal; it may be a desire to please one's family, a sense of duty, or a wish to excel. Whatever it is, an idea may stimulate to extraordinary achievements. Adopt some compelling aim if you have none. A vocational aim often serves as a powerful incentive throughout one's student life. An idea may operate for even more transient purposes; it may make one oblivious to present discomfort to a remarkable degree. This is accomplished through the aid of suggestion. When feelings of fatigue approach, you may ward them off by resolutely suggesting to yourself that you are feeling fresh.