What Happens to the Human Body During Extreme Cold?

When exposed to freezing temperatures, the body initiates several physiological responses to maintain its core temperature and ensure survival. Understanding these processes can help individuals recognize and respond to the dangers they may face when out in the cold. After falling and dying of thirst or hunger, exposure is the next most common cause of death for people trapped in a wilderness survival situation.

(Beck Weathers is all too familiar with extreme cold, and his story is a warning to all) 

1. The Body’s Initial Response to Cold

When exposed to cold, the body prioritizes maintaining a core temperature of about 98.6°F (37°C). To conserve heat, blood vessels in the extremities constrict (vasoconstriction), directing blood flow toward vital organs. This process, while essential for survival, reduces circulation to fingers, toes, ears, and the nose, leaving them vulnerable to cold-related injuries.

2. Conditions That Arise in Extreme Cold

a. Frostnip and Frostbite

(Frostnip causes no lasting damage, but is the first warning sign of frostbite)

Frostnip occurs first, typically at temperatures around 32°F (0°C) or lower. It’s a superficial injury where the skin becomes red and tingly but doesn’t cause permanent damage.

Frostbite develops when skin and underlying tissues freeze, often at temperatures below 23°F (-5°C). The extremities—fingers, toes, ears, and the nose—are most commonly affected.

Stages of Frostbite:

Mild (Frostnip): Redness, tingling, and numbness.

Superficial Frostbite: Skin turns pale or white and feels hard; blistering may occur.

Severe Frostbite: Tissues become black and necrotic, potentially requiring amputation.

(When something turns black it means the underlaying tissue has died and there is no chance of keeping the affected part)

b. Hypothermia

Hypothermia occurs when the body loses heat faster than it can produce it, causing the core temperature to drop below 95°F (35°C).

Stages of Hypothermia:

Mild Hypothermia (95°F to 90°F): Shivering, numbness, and confusion.

Moderate Hypothermia (90°F to 82°F): Shivering stops, coordination deteriorates, and consciousness begins to fade.

Severe Hypothermia (Below 82°F): The heart slows, breathing becomes shallow, and death may occur without intervention.

c. Chilblains

Chilblains are painful, red, and itchy patches on the skin caused by prolonged exposure to cold, damp conditions just above freezing (32°F to 50°F or 0°C to 10°C). While not life-threatening, they can cause discomfort and skin damage.

d. Trench Foot (Immersion Foot)

Trench foot results from prolonged exposure to wet and cold conditions, typically between 30°F to 40°F (-1°C to 4°C). The feet become numb, swollen, and pale, and if untreated, tissue damage can occur.

3. Parts of the Body Affected First

Extremities (Fingers, Toes): Due to reduced blood flow, these areas are most vulnerable to frostbite and numbness.

Face (Nose, Ears, Cheeks): These are directly exposed to cold air, making them prone to frostbite.

Skin: The skin may lose moisture in cold, dry conditions, leading to cracking and chapping.

Respiratory System: Breathing in extremely cold air can irritate the lungs, especially in people with conditions like asthma.

Muscles and Joints: As the temperature drops, muscles lose flexibility and strength, increasing the risk of injury.

4. Preventing Cold-Related Conditions

Wear Appropriate Clothing: Layering with moisture-wicking, insulating, and windproof materials protects against heat loss.

Protect Extremities: Gloves, thick socks, and insulated boots shield the fingers and toes.

Stay Dry: Wet clothing accelerates heat loss; always keep dry in cold environments.

Monitor Symptoms: Early signs of frostbite (tingling, redness) or hypothermia (shivering, confusion) should prompt immediate action.

Stay Nourished: Eating high-energy foods and staying hydrated helps the body generate heat.

5. Long-Term Impacts

Repeated exposure to extreme cold can cause chronic issues such as arthritis, nerve damage, and sensitivity to cold.

Severe frostbite or hypothermia survivors may face permanent tissue damage or impaired circulation in affected areas.

Understanding the effects of extreme cold on the body is crucial for survival in harsh conditions. By recognizing the signs of cold-related conditions and taking preventive measures, you can protect yourself and others from the dangers of freezing temperatures.