Running in the heat may cause problems with heat cramps, heat exhaustion, and heat stroke. Athletes who suffer from heat cramps will experience muscle cramps or spasms, heavy sweating and a normal body temperature.
Athletes who are experiencing heat exhaustion will find themselves sweating profusely, a drop in blood pressure, normal or slightly elevated temperature, lightheadedness, nausea, vomiting, decreased coordination and possible fainting.
Athletes who experience heat stroke will exhibit high body temperatures, lack of sweating, red skin and altered consciousness. This is a medical emergency! People who are at greatest risk are those athletes who are exercising in hot humid conditions, are older, obese, wearing heavy clothing or running with an infection, fever or taking certain types of medications such as beta blockers, diuretics and amphetamines.