Neurological fatigue

“ We hear much of nervous prostration as an American disease. It is due to a variety of causes,—high living, late hours, ill-ventilated rooms, and climate; but chief of all the causes is the long hours of work under strong pressure. Work done in a hurry and without rest may accomplish many things, but it invariably causes a corresponding loss of nerve force. Fatigue, by checking bodily resistance, gives rise to all kinds of poisons in the system. Every part of the body feels the ill effect of continued exhaustion. ”

“ Further, the somewhat greater frequency and acuteness of headache in brain workers—although the difference between them and muscle workers in this regard has been exaggerated—is probably due in part to the greater sensitiveness of their nerves; but more so to the curious fact, discovered in careful experiments upon the nervous system, that the fatigue products of the nerve-cells are the deadliest and most powerful poisons produced in the body. Hence some brain workers can work only a few half-hours a day, or even minutes at a time ”

“ I do not say that strong men with robust constitutions never take neuralgia, but all my experience, and that I believe of nearly all medical men, go to prove that it is more frequently an accompaniment of a weakened frame of body, with a nervous system below par. This may have been occasioned by bodily fatigue combined with want of sleep, anxiety of mind, worry, &c., or from debility from whatever cause. ”

“ One of the most constant symptoms is a gradual decline in strength, either of body or mind, without any organic disease to account for it. If a man whose heart, lungs and kidneys have been proved sound begins to suffer from fatigue after an amount of exercise such as he would not previously have noticed, everything points to the fact of its being the result of some impairment in his nervous system. More particularly so if the tiredness is of an unpleasant nature. There is a delightful form of fatigue and there is a painful one. ”

“ This description of muscular fatigue lays the foundation for an understanding of the problem of nervous fatigue. The nerve cells, like the muscles, get clogged by the products of their own action. They then fail to carry nervous impulses freely, and the individual can do his mental or physical work only with excessive effort. Fatigue of nerve cells means that nature has limits of work in these cells. ”

“ It is capable of enormous demands on its powers and of enormous resistance. It is the last system to succumb in many diseases and in such a dire condition as starvation. It would seem to be only highly advantageous to the organism that its nervous system should be able to resist the oncoming of fatigue, with all the direful consequences that might follow its advent.
After thus analyzing the phenomena of fatigue in their manifestations in the various organs and tissues of a complex body, let us briefly consider fatigue as we feel it in ourselves. ”

“ The fatigued [54] person remains fatigued, consequently, until the accumulations of waste matter are removed by the normal action of the lungs, skin, and kidneys.
Fatigue is caused by both mental and physical work, and when excessive, affects the nervous system most disastrously. The body can and should respond to occasional extra drafts on strength and endurance; its flexibility and power of adjusting to varying conditions may even be stimulated thereby. But even slight fatigue, if continued and especially if associated with anxiety or worry, has caused many nervous and mental breakdowns. ”

“ Such failures of the nervous system are usually the result of overwork of some kind; it is simply tired out, and insists upon rest. The fatigue may be direct, from overeating or improper food, or it may come from general exhaustion from dissipation, worry or mental or physical overexertion. ”

“ It is a healthful sign that the rest-cure is fast going out of style. Wherever it has helped a nervous patient, the real curative agent has been the personality of the doctor and the patient's faith in him. The whole theory was based on ignorance of the cause of nerves. People suffering from "nervous exhaustion" are likely to be just as "tired" after a month in bed as they were before. Why not? Physical fatigue is quickly remedied, and what can rest do after that? What possible effect can rest have on the fatigue of a discouraged instinct? ”

“ The pleasantest occupations or amusements may cause such sheer bodily fatigue that we can do them no longer, and to attempt it causes pain. It would appear that every thing carried to this point—to the extent of exhausting the nerve-force of the centre stimulated—causes discomfort or pain, which is only to be removed by cessation of the particular stimulus, and the substitution of another, stimulating other centres, or by the rest of the whole nervous system. ”

“ To breathe properly and without a sense of suffocation may seem to require the sustained attention of the patient; or again, the voice may be suddenly lost.
More commonly, perhaps, neuropathy exhibits itself in an undue tendency to show signs of fatigue upon exertion of any sort, mental or physical. Sustained interest in any pursuit or task becomes impossible. Nameless fears and unaccountable sensations of dread establish themselves suddenly and without warning, and may be accompanied on the physical side by palpitation, flushing, headache, or acute digestive disturbances. ”

“ In the first year of his residence at Cambridge, symptoms of disordered health, especially in the circulatory system, began to show themselves; and it is by no means improbable, that these were indications of a tendency to derangement of the vital functions, which become ultimately fatal. A too rapid determination of blood towards the brain, with its concomitant uneasy sensations, rendered him frequently incapable of mental fatigue. ”

“ Notwithstanding that most of us doubtless believe that we know the symptoms of nervous fatigue well, physiologists have been able to discover only scraps of fact in this field. The isolated nerve of a cold-blooded animal, when artificially stimulated in the laboratory, can perform its work for many hours without showing the least sign of a diminution of power. Only when placed under unfavorable conditions, such as in light anesthesia, or when deprived of oxygen, does the nerve exhibit with continued stimulation a gradual loss of conductivity. ”

“ Both probably occurred in a greater percentage, but were frequently masked by other symptoms which occupied the patient’s attention to a greater extent. Fatigue and hunger are important factors, not only because they prepare the ground for an ensuing neurosis by breaking down the defensive reactions, but also in that when the patient is more sensitive and impressionable, the natural physical consequences of fatigue are misinterpreted by him as an evidence of an illness, and give rise to apprehension and fear. ”

“ Chronic fatigue of the muscles is undoubtedly, in some cases, a precursor, if not a cause, of copodyscinesia, and, according to Poore,4 is occasionally the expression of hyperæmia or mild inflammation of a motor nerve. Acute local fatigue has symptoms which are well known to us all after having taken violent exercise, cramp and pain being the two most prominent ones. ”

“ It follows from what has gone before that cerebral fatigue is a most important matter to be reckoned with in all the affairs of life, but especially in education, where the foundations for nervous vigor or weakness are being permanently established, and where relatively little can be accomplished in either intellectual or moral training unless the physical instrument of mind be kept in good repair. ”

“ Affecting specifically the brain, heart, arteries, stomach, intestines, liver, and glands of internal secretion, worry also has a general adverse effect on the nervous system.
This adverse effect is unmistakably expressed by the haggard, drawn, gaunt aspect of the man who habitually worries, and by his persistent sensations of fatigue. What has happened is that his nerve cells are being deprived of the nutrition they need in order to energise him properly. ”

“ The Influence of Fatigue.—Histologists find that the nuclei of nerve cells are shrunk as much as fifty per cent by extreme fatigue. Reasonable fatigue followed by proper recuperation is not harmful, but even necessary if the best development is to be attained ”

“ Fatigue of nerve centres is no doubt strictly analogous to fatigue of muscles.
“It is practically impossible for us, by voluntary exertion, to reach the degree of absolute fatigue, which the physiologist produces by electric stimulation of a nerve-muscle preparation. The sense of fatigue becomes so intense that voluntary effort cannot overcome it. So no man can produce asphyxia by simply holding his breath, because the besoin de respirer becomes irresistible ”

“ Next after fatigue the most valuable danger signal given us by our nerves is that commonest of all pains, headache. Indeed, it is not too much to say that headache is the most useful pain in the world. It has little to do with the condition of the brain, but occurs in the head chiefly because the nerves of the head and face are the most sensitive of all those in the body, and the first ones, therefore, to "cry out" when hurt. ”

“ Not only does overfatigue hinder growth, but it also results in the formation of certain toxins, or poisons, in the organism, which are particularly harmful to nervous tissue. It is these fatigue toxins that account for many of the nervous and mental disorders which accompany breakdowns from overwork. On the whole, the evil effects from mental overstrain are more to be feared than from physical overstrain.
The Effects of Worry.—There is, perhaps, no greater foe to brain growth and efficiency than the nervous and worn-out condition which comes from loss of sleep or from worry. ”

“ It is not hard for the delicate nerve junctions to throw off fatigue if given a chance. The way to give them this chance is not to use them. As we shall see in the next chapter, mental processes are made up of nervous disturbances passing here and there in the brain. If we allow ourselves to be occupied too continuously with the same lines of thought, we are evidently sending nervous disturbances over the same nerve junctions over and over again. In order to give those nerve junctions a chance to rest, what we have to do is to think about something entirely different. ”

“ The bad peripheral influence of constant fatigue of the eyes in study may so completely modify a young man's constitution as to make a wreck of him in a very few years, changing him from the state of habitual and conscious health to that of chronic neurosis of one sort or another. And, though it is doubtless on persons with congenital tendencies to nervous diseases that such a combination of bad influences produces its most serious effects, yet there unquestionably are a few persons in whom they appear to entirely generate the neurotic constitution. ”

“ It restores the energy lost by Nervousness or Indigestion; relieves Lassitude and Neuralgia: refreshes the Nerves tired by Worry, Excitement or Excessive Brain Fatigue; strengthens a Failing Memory, and gives Renewed Vigor in all Diseases of Nervous Exhaustion or Debility. ”

“ At the beginning the overwork may pass unnoticed, but since fatigue is accumulative it eventually results in a complete nervous breakdown, because fatigue really weakens the brain centers that control the muscles, although the feeling of being tired is primarily felt in the muscles themselves, "Women are predisposed to nervous trouble, and their nerves are weakened by the various sex functions. ”

“ It can readily be seen that if there should be an accumulation of waste material from faulty metabolism due to interference with transmission, fatigue would be produced sooner and with less work than in the individual normally excreting the poisons.
If one part of the body or one set of muscles is overworked fatigue neurosis will be produced. There may be loss of motor function due, not to interference with transmission of motor mental impulses, but to the fact that the organ, usually a muscle, becomes an unfit medium for the expression of the mental impulses. ”

“ Connections among the fibers that go to make up the nervous system cannot be made with ease and rapidity when the organism is fatigued. At such times there seems to be an unusually high resistance at the synapses or nerve junctions (where there is a lowering of resistance to the passage of a nerve current when habits are easily formed) . After a certain point of fatigue, whether in the acquisition of motor habits or the memorizing of information, in which the process is much the same, the rate of learning is much slower and the degree of accuracy much less. ”

“ The appearance of the sufferer is sufficient to indicate this, as the condition of the cerebral vessels and all the exciting causes act either by retarding the flow of the venous blood from the brain, or by impeding the respiratory movements. The effects of emotion, of mental fatigue, and of severe and long-continued muscular exertion are such that the nervous influence to the [Pg 187] muscles of respiration is increased, or the muscles themselves are debilitated through this general fatigue of the organism. ”

“ It is not, however, necessary to believe that fatigue, in the ordinary sense of the word, whether physical or mental, is the invariable accompaniment of paramnesia. If it is the presence of a condition resembling that of sleep or the hypnagogic state which predisposes to the experience, that condition may be produced by other circumstances. Distraction, excited hyperaesthesia simulating increased power, and various chronic psychic states due to a highly-strung or over-strained nervous system may all tend in the same direction, even though no sense of exhaustion is felt. ”