1. energy that raises the temperature of a body or substance.
3. a rise in temperature.
to cause to increase in temperature.
Heat is associated with molecular motion, and is generated in various ways, including combustion, friction, chemical action, and radiation. The total absence of heat is absolute zero, at which all molecular activity ceases.
. Heat Production.
Body heat is the byproduct of the metabolic processes of the body. The hormones thyroxine
increase metabolism and consequently increase body heat. Muscular activity also produces body heat. At complete rest (basal metabolism) the amount of heat produced from muscular activity may be as low as 25 per cent of the total body heat. During exercise or shivering the percentage may rise to 60 per cent. Body temperature is regulated by the thermostatic center in the hypothalamus
. A body temperature above the normal range is called fever
Heat Loss. Loss of body heat occurs in three ways: by radiation (heat waves), by conduction to air or objects in contact with the body, and by evaporation of perspiration. Some body heat is lost in exhalation of air and in elimination of urine and feces.
Applications of External Heat
Local applications of heat may be used to provide warmth and promote comfort, rest, and relaxation. Heat is also applied locally to promote suppuration and drainage from an infected area by hastening the inflammatory process; to relieve congestion and swelling by dilating the blood vessels, thereby increasing circulation; and to improve repair of diseased or injured tissues by increasing local metabolism.
Effects. Factors that determine the physiologic action of heat include the type of heat used, length of time it is applied, age and general condition of the patient, and area of body surface to which the heat is applied. Moist heat is more penetrating than dry heat. Prolonged applications of heat produce an increase in skin secretions, resulting in a softening of the skin and a lowering of its resistance. Extreme heat produces constriction of the blood vessels; moderate heat produces vascular dilation. Repeated applications of heat will result in an increased tolerance to heat so that the individual may be burned without being aware of it. Elderly persons and infants are more susceptible to burns from high temperatures.
Heat applied to an infected area can localize the infection; for this reason, external heat should not be applied to the abdomen when appendicitis is suspected, because it may lead to rupture of the inflamed appendix.
a disorder resulting from overexposure to heat or to the sun; long exposure to extreme heat or too much activity under a hot sun causes excessive sweating, which removes large amounts of salt and fluid from the body. When salt and fluid levels fall too far below normal, heat exhaustion may result. Called also heat prostration
. The early symptoms are headache and a feeling of weakness and dizziness, usually accompanied by nausea and vomiting. There may also be cramps in the muscles of the arms, legs, or abdomen. These first symptoms are similar to the early signs of sunstroke
, or heat stroke, but the disorders are not the same and should be treated differently. In heat exhaustion, the person turns pale and perspires profusely. The skin is cool and moist, pulse and breathing are rapid, and body temperature remains at a normal level or slightly below (in sunstroke the body temperature may be dangerously elevated). The patient may seem confused and may find it difficult to coordinate body movements; loss of consciousness seldom occurs.
Treatment. In cases of heat exhaustion, the victim should lie quietly in a cool place until transported to an emergency facility. The restoration of normal blood volume will be a priority. Stabilization of electrolytes is also important. If the person is able to safely swallow, sips of cool replacement fluid should be provided. Measures to reduce body temperature are employed.
If the condition is accompanied by cramps, the pain may be relieved by lightly stretching the affected muscles in addition to administering replenishing fluids. In cases of severe heat exhaustion and cramps, hospitalization may be necessary. Serum electrolyte levels are monitored to guide adequate replacement.
Prevention. Heat exhaustion and other heat disorders may be prevented by avoiding long exposure to sun or heat. The elderly, the very young, individuals with chronic diseases, and athletes exercising in the sun are at high risk. When the weather is very hot, or when working in an extremely hot place, it is essential to maintain adequate hydration. Regular rest periods are necessary. In the event of weakness or dizziness, persons should stop working at once and rest in a cool place.
It is possible for indoor temperatures to exceed the outdoor temperature. Poor ventilation can lead to an unhealthy situation that contributes to heat exhaustion. For this reason, adequate temperature control indoors is important in prevention of serious health problems.
latent heat the amount of heat absorbed or given off by a body without changing temperature, as when it undergoes a change of state.
specific heat the ratio of the heat capacity of a substance to that of water; it is equivalent to the amount of heat required to raise the temperature of one gram of the substance by one degree Celsius, since the corresponding value for water is defined as 1.0.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
heat (q), (hēt),
1. A high temperature; the sensation produced by proximity to fire or an incandescent object, as opposed to cold.
2. The kinetic energy of atoms and molecules, as well as rotation and vibration.
Farlex Partner Medical Dictionary © Farlex 2012
n. 1. Physics
a. A form of energy associated with the motion of atoms or molecules and capable of being transmitted through solid and fluid media by conduction, through fluid media by convection, and through empty space by radiation.
b. The transfer of energy from one body to another as a result of a difference in temperature or a change in phase.
2. The sensation or perception of such energy as warmth or hotness.
3. An abnormally high bodily temperature, as from a fever.
v. heated, heating, heats
1. To make warm or hot.
2. Physics To increase the molecular or kinetic energy of (an object).
To become warm or hot.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
1. A high temperature; the sensation produced by proximity to fire or an incandescent object, as opposed to cold. The basis of heat is the kinetic energy of atoms and molecules, which becomes zero at absolute zero.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
heat see DIOESTRUS.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005
1. A high temperature; the sensation produced by proximity to fire or an incandescent object.
2. The kinetic energy of atoms and molecules.
Medical Dictionary for the Dental Professions © Farlex 2012
Patient discussion about heat
Q. Is ligament heating better than an arthroscopic surgery? I have a partial tear in my left knee (acl) and they wanna operate on me. I heard heating it can solve the problem. is it true?
A. i never heard of "ligament heating" from what i know- ligament has limited ability to regenerate. if partially torn it may need only physiotherapy and care. but if it's torn more then it can heal by itself- you need surgery. this is why there's orthopedics- to evaluate the situation, give you a diagnosis and the recommended treatment. it's always good to second guess because they are only human. you can ask other orthopedics and see what they say.
Q. Depression related. How can one prevent another from acting in the heat of the moment? I've known a friend who has struggled with personal depression most of his life, and every once in a while it really gets to him (yesterday, for example). Usually he can try to brush it off by occupying himself with something else, but other times he can't, and ends up seriously considering things that he normally wouldn't; suicide being the most serious. I talked to him today, and he told me he felt fine, but I'm concerned that one day he might actually act on his feelings.
A. My suggestion is to keep frequent contact with your friend and keep them talking and sharing their problems and worries. Someone who may often think about suicide should not be left alone if that is possible, especially when there are those really dark days.
Someone needs to followup and make sure they take their medication. Its so easy to lapse on that. My wife keeps up with me, but sometimes, we both miss it. I have resorted to programming the appoinment calendar on my cell phone PDA to alert me twice a day at medicine time. That only works if I remember to turn the phone on.
My doctor provided me with additioanl medication for those bad days which really works. It usually makes me sleepy and soon I forget about the whole thing that seemed to be bothering me. Thise bad days pass and soon all is back on track. Its just soemthing I have learned to live with for many many years. There's not going to be a cure for me. I just do the best I can and let the chips fall where they may.
Q. i suffer from upper and lower back pain , and i use this heating pills and it does not do a thing !!! i paid a 50$ bucks for those and my back still hurts like hell ! what can i do to make it go away , or at least ease the pain by a bit ????
A. Low back pain is very very common. The best solution is to combine mellow physical activity (streching, walking, swimming) on a daily basis, with creams that have anti pain ingredients during extreme pain. If the pain is continuous you should see a doctor for some further evaluation. More discussions about heat
This content is provided by iMedix and is subject to iMedix Terms. The Questions and Answers are not endorsed or recommended and are made available by patients, not doctors.