The victim may be pale, tired, and have clammy skin with heavy sweating. Have the victim lie down. If vomiting occurs, do not give any more fluids. Usually the victim will recover with rest. Severe cases, though, may require a doctor's care.
Heat stroke is a more serious reaction to heat.
It is characterized by extremely high body temperatures and little or no sweating. The skin will be hot, dry and red. The victim often has a rapid pulse. There may be dizziness and nausea. Heat stroke is an immediate life-threatening emergency for which professional medical care is urgently needed.