HIEE

S = M-W-Hres-E-R-C-K Heat balance equation

M Metabolic Energy production

W Internal heat production

Hres Heat exchange in respiratory tract

E Skin evaporation

R Radiation

C convection

K conduktion

Radiation, convection, conducting, respiration, evaporation Heat exchange with the environment

water vapor resistance resistance to water vapor through clothing system

clothing, activity, posture changes, reduces exposure time, change location, seek shelter Behavioral adjustments

vasoconstriction, shivering regulatory mechanisms in cold

shivering increases metabolic heat production

vasoconstriction cold, tightens blood vessels

vasodilation heat, open up blood vessels. Transport heat away from core

vasoconstriction as response to cold increased blood pressure due to...

extremity cooling Hands, head and feet may suffer extra cooling

Lewis reaction severe cooling of hand results in drop in skin temperature

is Neuro-muscular performance is imparied by tissue cooling? yes

low body temp leads to maximal aerobic power reduced

general cooling body temperature under 35°C

hypothermia general cooling

How is person affected by hypothermia Reduced body function, fatigue, mental confusion, unable to take care of himself

frostnip Occurs on unprotected parts of skin. Tissue goes below 0°C, ice crystals starts to form

non-freezing cold injuries if tissue maintains 10-15°C for a long term, damage occur to structures of cells and tissues

IREQ mathematical description of body balance in cold

convection cooling wind

What happens with blood volume when sweating much? Sweating lead to fluid losses reducing the blood volume

Heat stroke High core temperature, 40-45°C

Heat syncope overloading of circulatory system

heat exhaustion severe heat stress

Why is it harder to know about fluid losses in a dry hot climate than in a hot wet? Because of fast evaporation of sweat

Heat cramp Cramps due to uncompensated loss of salt by sweating

burn injuries tissue damage

Wet Bulb Globe Temperature WBGT mått för att bedöma värmetermperatur

Predicted Heat Strain pHS används för att uppskatta den fysiologiska belastning på människor i varma miljöer

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