Body heat

“ This heat is used in keeping the body at that temperature which is best suited to [pg 193] carrying on the vital processes. All parts of the body, through oxidation, furnish heat. Active organs, however, such as the muscles, the brain, and the glands (especially the liver) , furnish the larger share. The blood in its circulation serves as a heat distributer for the body and keeps the temperature about the same in all its parts (page 33) .
Next to the production of heat, in the consumption of the body's energy, is the production of motion. ”

“ He rose to his feet.
"There is the matter of the body glow. I can control my body temperature, raising and lowering it as I choose. The greatest difficulty when I am among people is to keep it down to human body heat. ”

“ The effect of HEAT is to stimulate the organic functions of the body, but when considerable heat is applied for some time together its effect is to cause languor and lassitude, want of energy, a disinclination for exertion both bodily and mental; it has a depressing effect generally upon the animal functions or the nervous system, and there are some forms of disease that are distinctly traceable to heat as a cause. ”

“ If it is necessary for the body to rid itself of an excess of heat, the quantity of blood circulating in the skin is increased. This brings the blood near the surface, where more heat can be radiated and where it may cause an increase in the perspiration. On the other hand, if the body is in danger of losing too much heat, the circulation diminishes in the skin and increases in the internal organs. ”

“ 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.
CHAPTER V
Health, strength, and efficiency! ”

“ The body, even when exposed stark naked to the air, is not wholly without defense against heat and cold. It can, up to a certain point, itself regulate the expenditure of caloric by the intervention of the vaso-motor nerves that go to the capillaries of the skin. Cold provokes a shrinking of the little vessels, and, restraining the peripheric circulation, diminishes the radiation and the transpiration to such a degree as to protect the internal organs for a considerable time. ”

“ Taking food increases heat, probably because of [Pg 45] the muscular effort needed to eat it. Muscular work is another factor. And finally the whole matter of heat production seems to be under the control of the nervous system. Not much is known on this point except that there is a heat center in the medulla which plays an important part in heat production and whose influence is seen where the temperature shoots way up in disease just before death. ”

“ To understand how this happens, let us consider for a moment the nature of heat, and cold.—Heat is one of those stimuli which act upon the excitability, and support life: for if it was totally withdrawn, we should not be able to exist even a few minutes; and cold is only a diminution of heat. When heat is present, in a proper degree, or the atmosphere is about that degree of heat which we call temperate, it just gives such a stimulus, and keeps the excitability exhausted to such a degree, as to preserve the body in health ”

“ It is evident that if the skin is warm heat will be given off from it more rapidly than if it is cool; a condition in which the balance is being upset by the failure of the body to lose heat rapidly enough can be corrected, at least in part, by causing the skin to become warmer and so more heat to be given off. ”

“ Muscle-substance will only work within a limited range of temperature, and as the body is constantly losing heat by radiation, conduction, evaporation of sweat, and by other means, heat must be supplied. ”

“ Our vital powers should be trained to generate a good deal of heat; and what they have been trained to do, they should continue to perform. All the heat, I say, therefore, which the body will manufacture for itself, readily, it should be permitted to do. But the moment we depend, unnecessarily, on external means of warmth—as too much or too soft and warm bed clothing, and too warm an atmosphere—that moment our internal organs begin to be enervated, in a greater or less degree, whether we are sensible of it or not.
We should not sleep in the clothes we have worn during the day. ”

“ By what means does Nature supply deficiencies of internal heat and eliminate an injurious excess, and, in either case, restore the organs to the temperature which is most agreeable to the regular performance of the functions of life? The means are various. When food becomes insufficient, calorification is effected at the expense of the tissues of the animal, and it grows lean. When heat is produced in excess, the organism rids itself of it speedily by several outlets. The body may be cooled by radiation, by evaporation, or by conduction or convection. ”

“ As the warm blood recedes from the skin, a sensation of cold is felt, but when the blood returns, there is again the feeling of warmth. The sensation of cold prompts one to seek a warmer place, or to put on more clothing; while the sensation of heat, if it be oppressive, leads to activities of an opposite kind. Prompted in this way by the sensations from the skin, one voluntarily supplies the external conditions, such as clothing and heat, that affect the body temperature. ”

“ The thorax and organs cramped and lifted by pressure of the clothing. (From an X-ray photograph.—After Dickinson.)
No clothing, of course,—not even fur,—has any warmth in itself; it simply has the power of retaining, or keeping in, the warmth of the body that it covers. The best and most effective way of retaining the body warmth is to surround the body with a layer of dead, or still, air, which is the best non-conductor of heat known. ”

“ This heat can not be supplied artificially from without. It must be generated within the body. It therefore becomes obvious that the temperature outside of the body is not regulated for the purpose of supplying the body with heat. ”

“ A great pulse is produced either by some urgent necessity, such as an excess of heat in the heart requiring refrigeration, and, as it were, ventilation from without; or it may arise from leanness of the body, as we shall soon show. The excess of heat is occasioned either by natural causes, such as the ages of manhood and youth, or simply a hot season, place, or a warmer temperament; or by non-natural causes, such as the air which surrounds us being hotter than common, hot baths, exercises, food, wine, heating medicines ”

“ If this extraction of caloric exceeds the quantity produced by the vital system, the temperature of the body decreases, until it sinks below the point at which the functions of life can be performed. This declination of the heat of the body is gradual ”

“ Such is a rapid sketch of the principal chemical phenomena which, taking place throughout the entire system, kindle everywhere an evolution of more or less intense heat. There is no central organ, then, for feeding the vital fire—every anatomical element performs its share; and, if a nearly uniform temperature exists throughout the body, it is because the blood diffuses heat regularly into the various parts it bathes. ”

“ When cold air comes in contact with the skin and mucous membrane of the lungs, heat is removed from the body, as from a stove, to restore an equilibrium of temperature. The removal of heat from the body is greatest when we are in a current of cold air, or when a brisk, cold wind is blowing upon us. ”

“ When the motions of any vessels become retrograde, less heat of the body is produced; for in paroxysms of vomiting, of hysteric affections, of diabetes, of asthma, the extremities of the body are cold: hence we may conclude, that these symptoms arise from the debility of the parts in action; for an increase of muscular action is always attended with increase of heat. ”

“ A person [64] who, after exercise that has produced free perspiration, stands in a current of cool air, is apt to take cold. The dryer the atmosphere, the more rapid is the cooling process. The most uncomfortable and oppressive atmospheric condition is that in which the air is heavily laden with moisture and the temperature high. Evaporation from the body is then slow, and the sensation of heat is oppressive.
It is a mistaken notion that clothing keeps the cold out. Its purpose is to keep the heat in, or, in other words, to prevent the rapid radiation of heat. ”

“ When applied in this way, it gradually abstracts the heat from the body, and thereby lessens the action of the system. It differs as much in its effects upon the body from the cold bath, as rest in a cold room, differs from exercise in the cold and open air. ”