Low Body Temperature (Hypothermia): Causes, Symptoms, Prevention, and Emergency Response

Hypothermia is core temperature <35°C (95°F). It is a medical emergency when severe.

Stages and Symptoms

• Mild (32–35°C): Shivering, cold sensation, tachycardia, tachypnea, vasoconstriction, mild confusion.
• Moderate (28–32°C): Shivering stops, marked confusion, drowsiness, slurred speech, bradycardia, hypotension, atrial fibrillation, paradoxical undressing.
• Severe (<28°C): Unconscious, absent reflexes, fixed dilated pupils, asystole/VF risk, appears dead.

Causes

• Primary: Environmental cold exposure (immersion, wind, wet clothing, inadequate shelter).
• Secondary: Impaired thermogenesis (hypothyroidism, hypoglycemia, adrenal insufficiency, malnutrition), impaired vasoconstriction (sepsis, alcohol, medications—beta-blockers, antipsychotics), CNS dysfunction (stroke, trauma, tumor).

Prevention

• Layered, moisture-wicking, windproof clothing; cover head/hands.
• Stay dry; change wet clothes immediately.
• Adequate nutrition/hydration; avoid alcohol/caffeine in cold.
• Buddy system; limit exposure time.
• Home heating ≥65°F (18°C) for elderly.

Emergency Management

1. Call 911.
2. Move to warm, dry environment.
3. Remove wet clothing; insulate with blankets (including head).
4. Handle gently (avoid triggering arrhythmia).
5. If alert: warm sweet fluids (no alcohol/caffeine).
6. Active rewarming (hospital): warm IV fluids, heated humidified oxygen, peritoneal/pleural lavage, ECMO for severe.
7. CPR if no pulse—continue until core >30°C; "no one is dead until warm and dead."