Thermoregulation
Thermoregulation is the maintenance of internal core body temperature by balancing heat generation with heat loss. 98.6 F (37 C) is the accepted norm for human body temperature. Hyperthermia occurs when your body absorbs or generates more heat than it can release. Your body is always adjusting to keep your body in homeostasis. Muscle contractions product heat as a by-product of metabolic processes. Because the body is very inefficient during exercise, ~75% of energy is released as heat (in other words, much of the energy used to fuel muscle contractions is lost as heat).
When you get too hot, your body needs to cool itself down by offloading some of the heat into the environment. Heat can be lost through the processes of conduction, convection, radiation and evaporation. Evaporation is the primary method of cooling the body during exercise. The evaporation of sweat is the body’s natural air conditioner. To change from a liquid to a gas vapor, the water molecules break and the energy used to break those bonds is taken from the body in the form of heat. When relative humidity is high, the air is close to saturation and holds a significant amount of water vapor. As a result, there is less room in the air for more water molecules to change from liquid to gas, so evaporation slows down. This makes the body's natural cooling system less effective. This leads to sweat pooling on the skin (feeling sticky), causing you to feel hotter, even though you are sweating more.
If the body is generating more heat than it can release - often due to effort, hot and humid conditions, dehydration or other risk factors - it can lead to serious health issues, such as heat exhaustion, heat stroke or death.
If the body is generating more heat than it can release - often due to effort, hot and humid conditions, dehydration or other risk factors - it can lead to serious health issues, such as heat exhaustion, heat stroke or death.
