Heat Stroke: Field Cooling First Aid

Heat stroke is a medical emergency. The body temperature climbs above about 104 degrees F, the brain and organs are damaged, and the person can die. The best chance of survival is cooling them fast, before and while waiting for the ambulance.

• All Outdoor Workers
• Supervisors
• First Aiders

Recognize heat stroke

• Confusion, slurred speech, strange behavior, agitation, seizures or loss of consciousness.
• Very hot skin that may be dry or sweaty. A person can still sweat in exertional heat stroke.
• Fast pulse, rapid breathing, headache, dizziness or nausea.
• Collapse during or after heavy work in heat.

If someone in the heat acts confused or collapses, treat it as heat stroke until proven otherwise.

Heat exhaustion vs. heat stroke

• Heat exhaustion: heavy sweating, weakness, dizziness, nausea, headache, muscle cramps, pale clammy skin. The person is alert. Move them to a cool place, loosen clothing, give cool water and watch closely.
• Heat stroke: confusion or collapse. This needs 911 and active cooling.

What to do (cool first, transport second)

1. Call 911 or your emergency number and give an exact location. See Calling 911 & Giving Your Location.
2. Move the person to shade or a cool area. Remove extra clothing, boots and PPE.
3. Cool immediately by the fastest method available:
   • Cold water immersion: place the person in a tub, stock tank or wading pool of cold water (ice added) up to the neck, supporting the head. This is the most effective method and can cool a person in minutes.
   • If immersion isn't possible, pour cold water over the body, or use ice-water-soaked towels or sheets over the whole body, changing them often. Put ice packs on the neck, armpits and groin.
   • Fan the person while wetting the skin.
4. Stay with them. Monitor breathing and consciousness. Be ready to start CPR if they stop breathing. See CPR & AED.
5. Keep cooling until emergency medical services take over. Aim to get the temperature below about 102 degrees F if a thermometer is available.
6. Do not give fluids to someone who is confused or unconscious.

Prevention reminder

• Water, rest and shade, plus acclimatization for new workers. See Heat Acclimatization
• A written heat plan with emergency cooling supplies on site, such as ice, a cooler and tubs. See Heat Illness
• Buddy system and regular checks on each other
• Training on symptoms and first aid for all workers

Last updated: October 8, 2026