Great Article About Effects of Heat And Cold In The Human Body

There is great effects of heat and cold in the human body.The human body is a heat-producing engine that must maintain its temperature within rather narrow limits through careful regulation of the flow of heat between the body and the environ­ment. The bodily mechanisms concerned include the rate of metabolic heat production, the effec­tiveness of circulation, skin temperature, and sweating. A crude but useful concept is to consider the body to be made up of a core and a shell.

Strictly speaking, no single temperature  can be called a core temperature, but it is customary in clinical literature to refer to the rectal measure­ment of body temperature because the rectum is a readily accessible part of the core or heat-producing part of the body, where temperature varies little from part to part at a given moment. The shell regulates the temperature gradient between the core and the environment and varies both in thickness and in rate of perfusion with blood.

How Change Occurs After  Effects of Heat And Cold In The Human Body

Environmental conditions affecting heat regula­tion include air temperature, wind, humidity, and radiant temperature. Man’s ability to perform in a given environment can be related to an integra­tion of the measurements of these climatic factors into the commonly used Wet Bulb Globe Tempera­ture Index. This index must be used with caution at extremes of temperature and exercise. Further­more, there is no single universal index.

Acclimatization occurs when man is exposed to high temperatures and can perform hard work with the least physiologic embarrassment. Sig­nificant physiologic adjustments take place in about five days: lower pulse and respiratory rate, lower body temperature, dilution and increase in volume of sweat. These changes are complete with­in two weeks and are maintained by continued periodic exposure.

Acclimatization to cold is less dramatic than to heat, and the subject is controversial. Acclima­tized persons are able to elevate metabolic heat production without resorting to shivering. Also, shivering begins at a lower temperature than in the unacclimatized. Shivering is a protective mechanism that results in as much as a four- or fivefold increase in metabolic rate. Acclimatiza­tion to cold is slow, taking two months or more, and may very well be a manifestation of the im­proved state of physical fitness that most people experience when chronically exposed to low tem­perature environments.

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