Heat Exhaustion and Heat Stroke on the Trail
Hiking in hot weather puts heavy demands on the body. Heat exhaustion can develop over hours of exertion, and if it is not addressed it can progress to heat stroke, which is a life-threatening emergency. Knowing the difference guides how quickly to act.
Heat exhaustion
Signs include heavy sweating, cool and clammy skin, weakness, dizziness, headache, nausea and muscle cramps. Move to shade, rest, loosen clothing, sip water or an electrolyte drink and cool the skin with wet cloths.
If symptoms worsen or do not improve within about an hour, seek medical help.
Heat stroke
Heat stroke is suggested by confusion, unusual behavior, slurred speech, fainting or seizures, often with hot skin. Call for emergency help immediately and start cooling the person as fast as possible with water, wet clothing and fanning, or immersion in cool water if available.
Do not give fluids to someone who is not fully alert.
Keep cooling while waiting for help, and move the person into the shade. Ice packs or cold wet cloths on the neck, armpits and groin help, but continuous cooling of as much skin as possible is the priority.
Reducing the risk
Hike in the cooler early morning, rest often in shade, wear light-colored loose clothing and a hat, and drink regularly while also eating salty snacks. Allow several days to adjust when traveling to a hotter climate.
Turn back early on very hot days; heat builds through the afternoon.