Exercise Physiology 1 - Temp Regulation

Conduction

Heat exchanged by 2 objects in contact (solid or fluid - liquid or gas)

Convection

Heat exchange by contact with a fluid that is flowing (fluid can be air or water)

How does convection cool body

Layer of warm air around body (zone of insulation) is constantly displaced by cold air when air temperature is lower than skin temperature.

Radiation

When heat is transferred from a warmer body to the cooler surroundings without physical contact instead using electromagnetic waves.

Things to note about Radiation

1) Occurs for 60% of heat loss at rest

2) When ambient temperature exceeds core temperature then it becomes a method of heat gain

Evaporation

Cooling of the body as a result of the vaporisation of sweat

Things to note about Evaporation

1) At rest it accounts for 25% heat loss but in hot conditions it accounts for 80% heat loss

2) To avoid overheating body uses blood to help regulate temp, heat from blood is transferred to sweat molecule and the skin is cooled when sweat evaporates

3) Excessive sweating leads to a loss of bodily fluids and when level of fluids drop the body's core temp will increase as it will lose it's biggest source of heat loss (because it's unable to sweat anymore)