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Desert dehydration and heat survival

High ambient temperatures combined with direct sun exposure can dehydrate a human body rapidly. Survival in arid environments depends on conserving moisture and avoiding physical exertion during peak heat hours.

Do this now

  1. Seek or build shade immediately: Move under rock ledges, desert vegetation, or construct a sun shelter using a tarp or clothing elevated 30 cm (12 inches) above the ground to allow airflow.
  2. Stop all unnecessary physical activity: Sit quietly during the hottest hours of the day, between 10 AM and 4 PM.
  3. Keep clothing on: Wear light-colored, loose-fitting, long-sleeved clothing. Keeping clothing on slows sweat evaporation, conserving your body's moisture reserves longer than exposed bare skin.
  4. Elevate yourself off the hot ground: Sitting directly on desert sand or rock exposes you to conductive temperatures exceeding 60 °C (140 °F). Sit on a pack or pad.
  5. Ration your sweat, not your water: Drink water when thirsty. Withholding water while working in extreme heat causes rapid heat exhaustion and heat stroke.

Recognizing heat emergencies

  • Heat exhaustion: Excessive sweating, pale or damp skin, headache, dizziness, nausea, and muscle cramps. Move to shade, loosen clothing, sip water, and cool skin with wet cloths.
  • Heat stroke: Medical emergency. Body temperature rises above 40 °C (104 °F), confusion, slurred speech, rapid pulse, and hot, dry or heavily sweating skin. Cool the person aggressively by pouring water over their head and torso, fanning them, and placing wet packs in armpits and groin.

Desert survival myths to avoid

  • Do not drink cactus fluid: Water from most wild cacti is highly acidic and contains toxic alkaloids that induce vomiting and diarrhea, accelerating dehydration.
  • Do not drink urine: Consuming urine concentrates salts and metabolic wastes in your kidneys, accelerating kidney damage and dehydration.
  • Do not travel by day: If you must walk to reach safety or cell reception, move only during early morning dawn, late evening dusk, or at night with a flashlight.