Heat exhaustion is one of the heat-related syndromes. Symptoms range in severity from mild heat cramps to heat exhaustion to potentially life-threatening heatstroke. Heat exhaustion can begin suddenly or over time, usually after working or playing in the heat, perspiring heavily, or being dehydrated.

Heat exhaustion signs and symptoms include:

• Cool, moist skin with goose bumps when in the heat
• Heavy sweating
• Faintness
• Dizziness
• Fatigue
• Weak, rapid pulse
• Low blood pressure upon standing
• Muscle cramps
• Nausea
• Headache

If you suspect heat exhaustion

Untreated, heat exhaustion can lead to heatstroke, which is a life-threatening condition. If you suspect heat exhaustion, take these steps immediately:

• Move the person out of the heat and into a shady or air-conditioned place.
• Lay the person down and elevate the legs and feet slightly.
• Remove tight or heavy clothing.
• Have the person drink cool water or other nonalcoholic beverage without caffeine.
• Cool the person by spraying or sponging with cool water and fanning.
• Monitor the person carefully.

Contact a doctor if signs or symptoms worsen or if they don't improve within one hour.

Call 911 or your local emergency number if the person's condition deteriorates, especially if he or she experiences:

• Fainting
• Agitation
• Confusion
• Seizures
• Inability to drink
• Core body temperature — measured by rectal thermometer — of 104 F (40 C) (heatstroke)