mechanisms of heat loss

• heat is lost via radiation, evaporation, convection and conduction
• the body attempts to maintain a constant core temperature through a balance of heat loss and heat gain via homeostasis
• body heat is gained through exercise, shivering or the application of external heat sources
• radiation: heat generated from within the body is given-off to the surrounding atmosphere
• Evaporation: when you sweat or your skin or clothing gets wet, the evaporation of that liquid promotes heat loss, the natural result is a cooling effect (evaporative cooling)
• convection: the process of air or water flowing by the skin and carrying away body heat
• conduction: the body conducts heat to whatever the skin is in direct contact with
• your body loses heat 25 times faster in water than air of the same temperature
• once a body has been in cold water for a long period of time most of the skin is cool with little blood flow
• areas of high heat transfer = neck, armpits and groin (these areas have high heat loss in the cold but allow high heat gain in heat)
• hypothermia is a medical phenomen that occurs when your body loses heat faster that it can produce heat
• mild hypothermia : 35 - 32 degrees celsius (shivering, numbness, lethargic, pale and cool to the touch)
• moderate hypothermia: 32 - 28 degrees celsius (confusion, weak pulse, slow breathing, slurred speech, lack of coordination)
• severe hypothermia : less than 28 degrees celsius (slow heart rate, slow breathing, dilated pupils, shivering, coma)