Temperature Regulation

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Temperature Regulation
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Definitions

• Core Temperature
• Measured as oral, aural, or rectal temperature
• Temperature of deep tissues of the body
• Remains relatively constant (?1ºF or ?0.6ºC)
  unless a person develops a febrile condition
• Nude person can maintain core temperature even
  when exposed to temperatures as low as 55ºF or as
  high as 130ºF in dry air
• Skin Temperature
• Rises and falls with the temperature of the
  surroundings

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Definitions

• Core Temperature
• Measured as oral, aural, or rectal temperature
• Temperature of deep tissues of the body
• Remains relatively constant (?1ºF or ?0.6ºC)
  unless a person develops a febrile condition
• Nude person can maintain core temperature even
  when exposed to temperatures as low as 55ºF or as
  high as 130ºF in dry air
• Skin Temperature
• Rises and falls with the temperature of the
  surroundings

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REGULATION OF BODY TEMPERATURE
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Heat Production

• Laws of Thermodynamics
• Heat is a by-product of metabolism
• Basal metabolic rate of all cells of the body
• Effect of muscular activity on metabolic rate
• Effect of endocrinology on metabolic rate (i.e.,
  thyroxin, growth hormone, testosterone)
• Effect of autonomic nervous system on metabolic
  rate

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Heat Loss

• How fast is heat transferred from deep tissues to
  the skin
• How rapidly is heat transferred from the skin to
  the surrounding environment

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How Fast Is Heat Transferred From Deep Tissues to
Skin

• Insulation Systems
• Skin and subcutaneous tissue (i.e., fat)
• Blood Flow
• Cutaneous circulation

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How Fast Is Heat Loss From the Skin to the
Surrounding Environment

• Radiation
• Conduction
• Evaporation

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Definitions

• Radiation
• Loss of heat by infrared heat rays (5-20?m or
  10-20X wavelength of visible light)
• Conduction
• Loss of heat from the body to a solid object
• Evaporation
• Loss of heat from the body through water vapor to
  the surrounding atmosphere
• Convection
• Effects of changes in the external environment
  (e.g., wind and water)

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Wind Chill Factor

• Effect of wind on skin temperature temperature
  of calm air that would produce equivalent cooling
  of exposed skin
• Cooling effect of air convection equals the
  square root of the wind velocity
• For example, air temperature feels twice as cold
  at a wind velocity of 4 mph than if the wind
  velocity is 1 mph

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ºF 35.74 0.6215T - 35.75V(100.16)
0.4275V(100.16)
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