Environmental Emergencies

← Back to December — CPR & First Aid

Heat, cold, and stroke are three of the most common outdoor medical emergencies — and they're often confused with each other or with simple exhaustion. When in doubt, treat it as serious and call 911.

Heat Exhaustion vs. Heat Stroke (Hyperthermia)

"Sunstroke" is an older, informal name for the same thing as heat stroke — sun exposure isn't required; a hot, humid day or overexertion in heavy gear causes it just as easily. Both heat exhaustion and heat stroke are stages of hyperthermia (dangerously elevated body temperature).

  • Heat exhaustion: heavy sweating, cool/clammy skin, weakness, nausea, headache, fast but weak pulse. Treat: move to shade or AC, remove excess clothing, sip water, cool with wet cloths or a fan. Improves within 30–60 minutes.
  • Heat stroke — a medical emergency: body temperature above 103°F, hot/red/dry or damp skin, confusion, slurred speech, rapid strong pulse, possible loss of consciousness. Call 911 immediately. Move to shade, remove excess clothing, cool aggressively with whatever is available — ice packs to neck/armpits/groin, cold water immersion if possible. Do not give fluids by mouth if the person is confused or not fully alert.

Hypothermia & Frostbite

  • Mild: shivering, fumbling hands, slurred speech, poor coordination. Treat: get out of wind and wet clothing, add dry insulating layers, give warm sweet liquids if fully alert.
  • Moderate to severe: shivering stops, confusion, drowsiness, slow weak pulse. This is an emergency — call 911, handle the person gently (rough handling can trigger cardiac arrest), insulate from the ground, and warm the core (chest/neck/head/groin) before the extremities.
  • Frostbite: numbness, waxy-white, or grayish-yellow skin. Rewarm only if you're certain it won't refreeze — use warm (not hot) water, never a direct flame or rubbing, which causes more tissue damage. Get medical care.

Stroke (Medical, Not Heat)

Unrelated to heat or cold — a stroke is a blood-flow event in the brain and needs care as fast as possible.

  • Recognize with BE-FAST: Balance loss, Eyes (vision change), Face drooping, Arm weakness, Speech difficulty, Time to call 911.
  • Note the time symptoms started — treatment options are time-sensitive, and responders will ask.
  • Don't give food, water, or medication (including aspirin) — some strokes involve bleeding, which aspirin can worsen.

Altitude Sickness

  • Acute Mountain Sickness (AMS): headache, nausea, fatigue, and dizziness above roughly 8,000 feet. Stop ascending, rest, hydrate, and descend if it doesn't improve.
  • HAPE (fluid in the lungs) and HACE (brain swelling) are rare but life-threatening progressions — persistent cough, extreme fatigue, confusion, or difficulty walking in a straight line mean descend immediately and seek medical care.

By Terrain

  • Desert: heat exhaustion and heat stroke risk is elevated year-round — hydrate before you're thirsty and plan activity for early morning.
  • Alpine: altitude sickness plus rapid temperature swings — hypothermia and sunburn/heat stress can both be in play the same day.
  • Water (saltwater & freshwater): cold water immersion causes hypothermia far faster than cold air — see April for the 1-10-1 rule on cold water shock.
  • Snow: hypothermia and frostbite are the primary risks — see January for winter-specific prevention.

Relevant Months

See also the December Weekly Content Calendar.