Heat Stress-Excess heat can place abnormal stress on your body. Temperature, humidity, radiant heat and air velocity affect the amount of heat stress you face. Your exposure can be intensified by age, weight, fitness, medical condition and acclimatization to the heat. Your body reacts to heat by circulating blood and raising your skin's temperature. The excess heat is then released through the skin.
Physical activity can limit the amount of blood that flows to the skin to release heat.
Sweating can also maintain a stable body temperature if the humidity level is low enough to permit evaporation and if the fluids and salts you lose are adequately replaced. When your body cannot release heat, it stores it. This raises your core temperature and heart rate putting your health at risk. Heat cramps often occur in tired muscles when a person drinks large quantities of water but fails to replace the body's salt. To relieve cramps drink sports beverages.