THE HUMAN ANIMAL
How do we stay warm? How do we produce heat? How do we regulate our core temperature?
Heat Regulatory Mechanism:
We “evolved” in the tropics and subtropics.
Therefore, we have a very sensitive and efficient heat regulatory mechanism.
We are naked, hairless, with sweat glands.
All warm-blooded animals use the evaporation of water to cool.
Humans sweat; the evaporation of water off the skin cools the skin and blood.
Fur-covered mammals & birds pant, evaporating water out of the lungs thus cooling the pulmonary circulation.
Heat Production and Heat Loss
Basal metabolism, we burn glucose as a fuel to produce heat.
Metabolic activity set by thyroid, can be increased 5x’s.
Exercise – muscle activity.
Voluntary or involuntary = shivering, increases up to 10x’s.
Vasoconstriction in the skin.
Piloerection – hair stands on end.
Abolition of sweating.
Conduction: Transfer of heat from one solid object to another.
0% – 40% depending upon the type of solid material
Convection: Transfer of heat from a solid object into the air or water.
0% – 40% depending upon air penetration
Radiation: Transfer of heat by infrared radiation.
5% – 80% depending upon surrounding temperature
Evaporation: Transfer of heat by the evaporation of water.
0% – 90% depending upon vapor pressure & moisture
This blog is powered by the Wilderness Medicine Newsletter, now celebrating 20 years of publication. The WMN is published and distributed online six times each year by TMC Books, and subscriptions cost as little as $10 per year. To find out more, or to subscribe online, click here.