What Causes Heat-Related Illnesses
Normally, during daily activities your body will lose four liters of fluid. This is generally replaced by the fluid you drink and the food you eat. However, different factors, such as exercise, sweating, diarrhea, temperature, or altitude, can significantly increase the amount of fluid required to sustain your normal body temperature.
The most common cause of increased fluid loss is exercise and sweating. Sweat consists mostly of water and some electrolytes, specifically sodium and chloride ions. As long as you can sweat and the sweat can evaporate, you can continue to cool yourself efficiently. But if for some reason the sweating mechanism begins to fail or the sweat cannot evaporate, then the cooling mechanism will fail.
On hot, very humid days, your cooling mechanism is extremely inefficient, and it becomes fairly easy to overheat because the sweat cannot evaporate. The evaporation of sweat accounts for 90% of your cooling ability. Also, your ability to sweat diminishes as you become dehydrated. If this occurs you can be at risk for any and/or all heat related illnesses.
Summertime activity, whether on the playing field or the construction site, must be balanced with measures that help your body to cool and prevent heat-related illness.