Heat exhaustion refers to overheating of the body due to excessive loss of water or, in rare cases, salt depletion. Symptoms include thirst, headache, pallor, dizziness and possibly nausea or vomiting. In severe cases, your heart may race and you may feel disoriented.
Heatstroke occurs when the body's thermoregulatory system stops working.
Many of the symptoms are the same as for heat exhaustion. However, cessation of sweating, difficulty walking, disorientation and fainting or unconsciousness indicate heatstroke. Runners suffering heatstroke will be too disoriented to help themselves. Learn to recognize the symptoms and treat the problem in someone else. Quick Tip Weight is a greater handicap than age.