I. Physiology: Nervous system

  1. Hypothalamus controls Thermoregulation
  2. Parasympathetic nervous system controls sweating
  3. Sympathetic nervous system controls skin blood flow
    1. Vasodilation results in heat dissipation

II. Physiology: Temperature variation

  1. Core Temperature rises 1 C per 30 C Ambient Temperature
  2. Core temp. rise 0.6 C, raises basal metabolic rate 10%
  3. Cellular damage occurs at core Body Temperature above 104 F (40 C)
  4. Cellular death occurs at core Body Temperature above 107.6 F (42 C)
    1. Known as Thermal Maximum
    2. Cell death occurs at variable duration of exposure: 42 C (107.6 F) for 45 minutes to 8 hours

III. Physiology: Heat Dissipation Mechanisms

  1. Sweat evaporation (primary mechanism at >68F or 20C)
    1. Optimally dissipates 600 kcal/hour
    2. Sweat loss maximum 3 Liters/hour
      1. Endurance athletes lose up to 1.5 Liters/hour
    3. Rate of perspiration in hot environments is almost exclusively responsible for heat loss
    4. Perspiration becomes less effective in humid environments
  2. Heat Conduction
    1. Cold packs applied to skin
    2. Cold water emersion is the most expedient way to dissipate heat
  3. Heat Convection (Air or wind flows over skin)
    1. Body can dissipate heat with greater air circulation
    2. Cooler air also dissipates heat by providing a larger gradient between Body Temperature and air Temperature
    3. Permeable clothing allows for greater heat dissipation
  4. Heat Radiation (Infrared dissipation)
    1. Radiant energy is resorbed or reflected
    2. Light-colored clothing reflects away heat

IV. Physiology: Heat Adaptation

  1. Athletes may require 10-14 days to acclimitize to Exercise in hot environments
  2. Mechanisms
    1. Improved sodium retention
    2. Increased Glomerular Filtration Rate
    3. Increased cardiovascular performance
    4. Heat shock proteins

V. Physiology: Children and increased propensity for Heat Illness

  1. Greater surface area to body mass
  2. Slower sweat rates
  3. Sweating initiated at a higher Temperature set point
  4. Sweat is more dilute
  5. Slower accilimitization to hot environments than adults
  6. Decreased thirst response

Images: Related links to external sites (from Google)

Ontology: Physiologic Thermoregulation (C0005905)

Definition (GO) A homeostatic process in which an organism modulates its internal body temperature. [GOC:jl]
Definition (NAN) The physiologic process of regulating heat and energy within the body for purposes of protecting the organism
Definition (MSH) The processes of heating and cooling that an organism uses to control its temperature.
Definition (PSY) Homeostatic behavioral or physiological responses that maintain body temperature within a viable range. Compare THERMAL ACCLIMATIZATION.
Definition (CSP) processes of heating and cooling that an organism uses to control its temperature.
Definition (NOC) Balance among heat production, heat gain, and heat loss
Concepts Organism Function (T040)
MSH D001833
SnomedCT 386726008, 1942004, 276535009
English Body Temperature Regulation, Body Temperature Regulations, Regulation, Body Temperature, Regulations, Body Temperature, Temperature Regulation, Body, Temperature Regulations, Body, Thermoregulation, Thermoregulations, Body Thermoregulation, body temperature regulation, thermoregulation, Physiologic Thermoregulation, Thermo regulation, THERMOREG, BODY TEMPERATURE REG, REG BODY TEMPERATURE, TEMPERATURE REG BODY, regulation of body temperature, temperature homeostasis, regulations body temperature, Body temperature regulation, Thermoregulation, function (observable entity), Thermoregulation, function, Thermoregulation (Body)
Swedish Kroppstemperaturreglering
Czech termoregulace
Finnish Kehon lämpötilan säätely
French Régulation de la température corporelle, Thermorégulation, Thermorégulation du corps, Régulation de la température du corps, Thermorégulation corporelle
Italian Termoregolazione, Regolazione della temperatura corporea
Russian TEMPERATURY TELA REGULIATSIIA, TERMOREGULIATSIIA, TEPLOPOTERIA, ТЕМПЕРАТУРЫ ТЕЛА РЕГУЛЯЦИЯ, ТЕПЛОПОТЕРЯ, ТЕРМОРЕГУЛЯЦИЯ
Japanese 熱損失, 体温調節
Croatian TJELESNA TEMPERATURA, REGULACIJA
Polish Regulacja ciepłoty ciała, Termoregulacja
Spanish termorregulación (entidad observable), termorregulación, Regulacion de la Temperatura Corporal, Termorregulacion, Regulación de la Temperatura Corporal, Termorregulación
German Thermoregulation, Körpertemperaturregelung, Temperaturregelung, Körper-
Dutch Lichaamstemperatuur, regulatie van de, Regulatie van de lichaamstemperatuur, Thermoregulatie
Portuguese Regulação da Temperatura Corporal, Termorregulação