Heat Exhaustion: Symptoms, First Aid & When to Seek Emergency Care

Heat exhaustion is a heat-related illness from dehydration and failed thermoregulation. It can progress to life-threatening heat stroke if untreated.

Key Symptoms

• Heavy sweating
• Cool, moist, clammy skin
• Rapid, weak pulse
• Weakness, fatigue, dizziness
• Headache
• Nausea or vomiting
• Muscle cramps
• Slight hypotension
• Pale or flushed complexion

Immediate First Aid

1. Move to cool/shaded area (ideally air-conditioned).
2. Lie down, elevate legs.
3. Remove excess clothing.
4. Cool with wet cloths, misting, fan; ice packs to neck, axillae, groin.
5. Sip cool water or electrolyte drink (if alert, not vomiting).
6. Monitor; symptoms should improve within 30 min.

Red Flags → Call 911 / Go to ER

• Altered mental status (confusion, agitation, seizures, coma).
• Core temperature ≥104°F (40°C).
• Hot, dry skin (sweating stopped) → heat stroke.
• Persistent vomiting, unable to rehydrate.
• Syncope not resolving with supine position.

Prevention

• Hydrate before/during/after heat exposure.
• Acclimatize gradually over 7–14 days.
• Light, loose, light-colored clothing.
• Schedule strenuous activity for cooler hours.
• Know medications that impair heat tolerance (diuretics, anticholinergics, beta-blockers, stimulants).