Exercising in hot weather can cause side effects like:
1. Heat cramps: Muscle cramps, usually in the legs or stomach (caused by loss of salt from sweating). This may be the first sign of overheating.
2. Heat exhaustion: Heavy sweating, cold and clammy skin, nausea and vomiting.
3. Heatstroke: When the body temperature rises above 104°F (40°C).
Heatstroke is a life-threatening condition.