Heat illness and dehydration

Recognize when ordinary fatigue has become heat illness and cool a person before transport decisions.

General field reference, not medical advice. Use it to support immediate decisions, then follow 911, rescue coordinators, medical professionals, current warnings, and local agency guidance.

Act now

1. Stop exertion and move the person to shade or a cooler environment.

2. Remove unnecessary clothing and begin active cooling.

3. Call 911 for confusion, collapse, seizure, loss of consciousness, or other signs of heat stroke.

4. Cool continuously while help is coming.

5. Give fluids only when the person is alert and able to swallow normally.

Heat exhaustion and heat stroke are not the same

Heat exhaustion may include heavy sweating, weakness, headache, nausea, dizziness, thirst, irritability, and reduced performance. Stop activity, cool the person, and monitor closely. Symptoms that do not improve promptly justify medical help.

Heat stroke is a life-threatening emergency. Altered mental status is a critical warning sign. Confusion, irrational behavior, collapse, seizure, or unconsciousness in a hot or exertional setting requires immediate emergency activation and rapid cooling.

Skin may be hot and either wet or dry. Do not wait for sweating to stop before treating suspected heat stroke as an emergency.

Cool first

Move to shade, remove excess layers, wet the skin, fan aggressively, and place cold wet cloths or wrapped cold packs around the neck, armpits, and groin. Cold-water immersion can cool rapidly when it can be performed safely with continuous airway monitoring and without delaying emergency coordination.

Do not give fluids to a confused, vomiting, seizing, or unconscious person. Do not use fever-reducing medications for heat stroke.

Plan around heat load

Temperature alone does not describe the workload. Direct sun, humidity, altitude, pack weight, steep terrain, poor sleep, dehydration, illness, and lack of acclimatization all matter.

• Move strenuous work to cooler hours.

• Use shade and planned rest before symptoms begin.

• Carry more water than the route appears to require and identify backups.

• Adjust pace to the least heat-acclimatized member.

• Watch partners for behavior and coordination changes.

• Avoid leaving a person or animal in a parked vehicle.

An animal recovery or pack-out does not justify ignoring heat illness. Divide loads, change timing, add water, or seek help before the group loses safe options.