Braving the Elements: How Extreme Cold Affects the Human Body
In February 1959, nine experienced hikers died during a skiing expedition in Russia’s Ural Mountains. In the middle of the night, they cut their way out of their tent from the inside and fled into temperatures nearing –30°F.
Weeks later, rescuers found them scattered across the snow — some barefoot, some partially undressed, some with strange injuries. One hiker had even bitten off part of his own hand.
For decades, the incident raised unsettling questions. Why would trained mountaineers make such dangerous choices?
The answer lies in how extreme cold affects the human body.
How the Body Responds to Extreme Cold
The human body works hard to maintain a core temperature of around 98.6°F. When exposed to severe cold, that balance — known as homeostasis — begins to fail.
Once heat loss outpaces heat production, survival becomes a race against time.
The Hypothalamus: Your Internal Thermostat
Body temperature regulation is controlled by the brain and circulatory system working together to conserve heat and protect vital organs.
When your body senses cold, the hypothalamus (a region of the brain) activates protective responses. One of the first is vasoconstriction, where blood vessels narrow to reduce heat loss and protect vital organs.
This helps preserve the brain and heart — but it comes at a cost. Blood flow to the hands, feet, ears and nose decreases, making them vulnerable to frostbite.
The Stages of Hypothermia
Hypothermia symptoms begin when core body temperature drops below 95°F. From there, they continue to escalate as the body loses its ability to regulate heat.
Mild Hypothermia (89.6–95°F)
The body is under stress but still trying to protect itself. Symptoms can include:
- Pale skin
- Rapid heartbeat
- Intense shivering (the body’s attempt to generate heat)
- Confusion, irritability and poor decision-making
As brain function declines, people may feel sleepy or disoriented: a dangerous state in cold environments.
Moderate Hypothermia (82.4–89.6°F)
The body begins to lose its ability to regulate heat. It’s often accompanied by:
- A lack of shivering (a critical warning sign)
- Slurred speech
- Hallucinations
- Muscle stiffness
- Slowed breathing and heart rate
At this stage, the body’s heat-regulating systems are failing.
Severe Hypothermia (Below 82.4°F)
Vital systems slow dramatically, and the situation becomes life-threatening. Symptoms often include:
- Loss of consciousness
- Extremely slow heart rate and breathing
- Risk of heart or respiratory failure
Some people experience paradoxical undressing, a phenomenon where blood vessels suddenly widen, creating a sensation of intense warmth. Confused and overheated, individuals may remove clothing: a fatal mistake in freezing conditions.
What Happened at Dyatlov Pass?
Modern research suggests the hikers were likely forced from their tent by a small avalanche. Injured and disoriented, they sought shelter in nearby woods amid extreme wind and cold — many without shoes.
As hypothermia progressed, impaired judgment and delirium explained the hikers’ tragic and seemingly irrational actions. The cold, not mystery or myth, proved fatal.
Who Is Most at Risk for Hypothermia?
Hypothermia causes up to 1,500 deaths each year in the U.S. Those most at risk include:
- Young children
- Older adults
- People experiencing homelessness
- Individuals under the influence of drugs or alcohol
- Anyone unable to regulate body temperature or seek shelter
Understanding the Science Can Save Lives
Extreme cold is a reminder of how closely the body depends on its environment. Studying medical sciences helps explain these responses and equips future healthcare professionals to recognize and treat life-threatening conditions like hypothermia.
The University of Florida offers fully online graduate programs in medical sciences and is designed with flexibility for working professionals.
Explore our online graduate certificates and master’s degrees to see which path best aligns with your career goals.
Sources:
https://theconversation.com/what-happens-to-your-body-when-you-get-left-in-the-cold-212637
https://doi.org/10.1016/j.wem.2019.10.002
https://my.clevelandclinic.org/health/diseases/21164-hypothermia-low-body-temperature
https://www.newyorker.com/magazine/2021/05/17/has-an-old-soviet-mystery-at-last-been-solved
