Heat, Cold, Water

Part of First Aid

Without climate-controlled buildings, central heating, or air conditioning, environmental injuries become leading causes of death. Recognizing and treating hypothermia, heat stroke, frostbite, and near-drowning can save lives that would otherwise be lost to exposure.

Heat-Related Injuries

Heat Exhaustion

Heat exhaustion is the body’s warning that its cooling system is overwhelmed. It is survivable and reversible if caught early, but progresses to heat stroke if ignored.

Signs:

• Heavy sweating (the body is still trying to cool itself)
• Cool, pale, clammy skin
• Weakness, dizziness, nausea
• Headache, muscle cramps
• Core temperature elevated but below 40 degrees Celsius
• The person is still mentally alert, though may be confused

Treatment:

1. Move to shade or the coolest available location immediately.
2. Lay the person down with legs elevated 15-20 cm.
3. Remove excess clothing.
4. Cool actively: wet cloths on neck, armpits, and groin (where major blood vessels run close to the surface). Fan if possible.
5. Give water with salt --- 1/4 teaspoon of salt per liter. Small, frequent sips (250 ml every 15 minutes). Do not give large volumes at once as it can cause vomiting.
6. Rest for at least 24 hours before returning to any physical exertion.

Heat Stroke

Life-Threatening Emergency

Heat stroke has a mortality rate exceeding 50% without aggressive cooling. It is the most time-critical environmental emergency. Every minute of delay in cooling increases the risk of brain damage and death.

Signs --- the critical differences from heat exhaustion:

• Skin is hot and dry (sweating has stopped --- the cooling system has failed)
• Skin may be red or flushed
• Core temperature above 40 degrees Celsius (104 degrees Fahrenheit)
• Altered mental status: confusion, slurred speech, combativeness, seizures, unconsciousness
• Rapid, strong pulse

Treatment:

1. This is an emergency. Begin cooling immediately --- do not waste time on anything else.
2. Immerse the person in cool water if any body of water, trough, or large container is available. This is the fastest and most effective method.
3. If immersion is not possible, pour water over them continuously while fanning. Concentrate on the head, neck, armpits, and groin.
4. Pack wet cloths around the neck, armpits, and groin.
5. Continue aggressive cooling until mental status improves or the person begins shivering (a sign that core temperature is dropping toward normal).
6. Once responsive, give fluids slowly --- salted water as above.
7. Do not leave them alone for 48 hours. Heat stroke can cause organ damage that manifests hours later. Monitor for dark or reduced urine (kidney failure), continued confusion (brain injury), or yellow skin/eyes (liver damage).

Prevention in Hot Climates

Strategy	Implementation
Hydration	250 ml water every 30 minutes during physical work in heat
Work schedule	Hard labor only in early morning and evening, rest during midday
Headwear	Wide-brimmed hat, wet cloth over head and neck
Salt intake	Add 1/4 teaspoon salt per liter of drinking water during heavy sweating
Acclimatization	Gradually increase heat exposure over 7-10 days when moving to a hotter environment

Cold-Related Injuries

Hypothermia

Hypothermia occurs when the body’s core temperature drops below 35 degrees Celsius (95 degrees Fahrenheit). It kills more people in survival situations than almost any other cause because it is insidious --- the victim’s judgment deteriorates as the condition worsens, making them unable to save themselves.

Stages and signs:

Stage	Core Temp	Signs	Mental State
Mild	35-32 C	Shivering, goosebumps, cold hands/feet, fumbling with tasks	Alert but poor decisions, apathy beginning
Moderate	32-28 C	Violent shivering then shivering stops, muscle stiffness, slurred speech, blue lips	Confused, drowsy, may resist help
Severe	Below 28 C	No shivering, rigid muscles, very slow pulse, shallow breathing	Unconscious or semi-conscious

Paradoxical Undressing

In moderate to severe hypothermia, victims sometimes feel burning hot and begin removing their clothing. This is a well-documented neurological phenomenon, not a sign of recovery. If you find someone confused and partially undressed in cold conditions, assume hypothermia.

Treatment by stage:

Mild hypothermia:

1. Move to shelter, out of wind and rain.
2. Replace wet clothing with dry clothing or blankets.
3. Give warm (not hot) sweet drinks --- sugar provides immediate fuel for heat generation.
4. Apply insulation: wrap in blankets, sleeping bags, or dry leaves/grass. Insulate from the ground (ground contact steals heat faster than air).
5. Skin-to-skin contact with a warm person in a shared blanket or sleeping bag is highly effective.
6. Encourage gentle movement to generate heat --- but not vigorous exercise, which can cause dangerous heart rhythms in a cold heart.

Moderate hypothermia:

1. Handle the patient extremely gently. A cold heart is electrically unstable --- rough handling can trigger cardiac arrest.
2. Do not allow the patient to walk or move vigorously.
3. Lay them horizontal. Do not sit them up.
4. Apply heat to the core only: warm water bottles or heated stones (wrapped in cloth to prevent burns) placed against the chest, armpits, and groin. Do not warm the extremities first --- this sends cold blood from the limbs to the heart and can cause cardiac arrest (afterdrop).
5. Insulate thoroughly. Cover the head --- 30-40% of heat loss occurs through an unprotected head.
6. Warm, humidified air is beneficial --- have the patient breathe through a warm, damp cloth.
7. If available, give warm sweet fluids only if the patient is alert enough to swallow without choking.

Severe hypothermia:

1. The patient may appear dead --- cold, stiff, no visible breathing, no palpable pulse. Do not assume they are dead. People have survived core temperatures as low as 13.7 degrees Celsius. The saying is: “Nobody is dead until they are warm and dead.”
2. Handle with extreme gentleness.
3. Slow rewarming of the core as described above.
4. If no pulse is detectable after 60 seconds of careful checking, begin CPR. Continue CPR until the person is rewarmed.
5. Rewarming from severe hypothermia takes hours. Do not give up.

Frostbite

Frostbite is the freezing of tissue, most commonly affecting fingers, toes, ears, nose, and cheeks.

Stages:

Stage	Appearance	Sensation	Outcome
Frostnip	Red, then white patches	Painful, then numb	Full recovery
Superficial frostbite	White or grayish-yellow, waxy	Numb, feels wooden	Blisters, heals in weeks
Deep frostbite	Hard, white or mottled blue	Completely numb	Tissue death, possible amputation

Treatment:

1. Move to a warm environment before attempting rewarming. Do not thaw frostbitten tissue if there is any chance it will refreeze --- thaw-refreeze cycles cause far more damage than remaining frozen.
2. Remove wet clothing and any constricting items (rings, tight boots).
3. Rewarm by immersing in water at 37-40 degrees Celsius (warm to the touch, not hot). Test with your elbow --- it should feel comfortably warm. Rewarming takes 20-40 minutes.
4. Rewarming is extremely painful. Provide pain management: willow bark tea, alcohol in moderate amounts, something to bite on.
5. Do not rub or massage frostbitten tissue --- ice crystals in the cells will tear tissue apart.
6. Do not rewarm with direct heat (fire, hot stones) --- the tissue has no sensation and will burn without the patient feeling it.
7. After rewarming, blisters will form. Clear blisters can be left intact. Blood-filled (hemorrhagic) blisters indicate deep damage --- leave these intact and protect them carefully.
8. Loosely bandage with clean cloth between each affected finger or toe.
9. Keep the affected area elevated to reduce swelling.
10. Full tissue demarcation (determining what is dead vs. alive) takes 4-6 weeks. Do not amputate early unless active infection develops.

Near-Drowning

Rescue

1. Do not become a second victim. An actively drowning person will climb on top of you and push you under. Extend a pole, branch, rope, or throw a buoyant object first.
2. If you must enter the water, approach from behind and tow the person by their clothing or hair.
3. Once out of the water, immediately assess breathing.

Treatment

1. Open the airway. Tilt the head back and lift the chin. Clear any visible debris from the mouth.
2. Check for breathing for 10 seconds. Look for chest rise, listen for air, feel for breath on your cheek.
3. If not breathing, begin rescue breathing: 2 full breaths, then check for a pulse.
4. If no pulse, begin CPR: 30 chest compressions (5-6 cm deep, at a rate of 100-120 per minute), then 2 breaths. Continue without stopping.
5. Do not attempt to drain water from the lungs by holding the person upside down or pressing on their abdomen. Aspirated water is absorbed into lung tissue and cannot be drained mechanically. Abdominal thrusts waste time and risk vomiting.
6. Once breathing is restored, place the person in the recovery position (on their side, head tilted back).
7. Monitor for 24-48 hours. Secondary drowning can occur hours later as fluid in the lungs causes inflammation and breathing difficulty. Watch for persistent coughing, difficulty breathing, or declining consciousness.

Cold Water Drowning

In cold water, the body cools rapidly and hypothermia develops within minutes. However, cold water also triggers the mammalian diving reflex, which can protect the brain. People have survived 30+ minutes of submersion in very cold water. Continue CPR for at least 60 minutes in cold-water drowning cases, especially with children.

Prevention

• Never swim alone.
• Respect moving water --- a knee-deep current can knock an adult off their feet.
• When crossing rivers, use a pole for stability, unbuckle pack straps (so you can ditch the pack if you fall), cross diagonally downstream, and link arms in a group.
• Children must be supervised at all times near any body of water.

Key Takeaways

• Heat stroke kills within hours --- cool the patient immediately and aggressively by any means available.
• Hypothermia victims must be rewarmed core-first and handled gently to avoid triggering cardiac arrest.
• Never thaw frostbite if refreezing is possible --- thaw-refreeze cycles are devastating.
• Near-drowning patients must be monitored for 24-48 hours for secondary drowning symptoms.
• Prevention is vastly more effective than treatment for all environmental injuries --- adjust work schedules, clothing, and hydration to conditions.