Heat exhaustion occurs when the body loses too much water and salt, usually through heavy sweating. It can progress to life-threatening heat stroke if it is not recognized and treated promptly.
Symptoms may include heavy sweating, headache, dizziness or lightheadedness, weakness, unusual fatigue, irritability, thirst, nausea or vomiting, muscle cramps, rapid heartbeat, elevated body temperature, and decreased urination.
Drink fluids regularly, take frequent breaks in a cool or shaded place, wear lightweight and light-colored clothing, avoid strenuous activity during the hottest part of the day, and gradually increase exposure when returning to outdoor work or exercise. Never leave children, older adults, or pets in a parked vehicle.
Move the person to a cooler location, have them rest, loosen or remove unnecessary clothing, cool the skin with wet cloths, misting, or a cool shower, and provide cool water or an electrolyte drink if they are alert and not vomiting. Do not resume strenuous activity that day.
Call 911 immediately for confusion, disorientation, slurred speech, fainting, seizures, inability to drink, very high body temperature, or hot skin that may be dry or heavily sweating. Begin rapid cooling while waiting for emergency help. Do not give fluids to a person who is confused, unconscious, or unable to swallow safely.
Sources: CDC/NIOSH and OSHA guidance on heat-related illness and first aid. This information is educational and does not replace an individual medical evaluation.
