Braving the Elements: What Extreme Cold Does to the Human Body
Want to learn how the human body holds up to extreme cold? There’s no better example than one of the most chilling mysteries of the 20th century: the Dyatlov Pass incident.
On February 1, 1959, nine hikers died on a skiing expedition through Russia’s Ural Mountains. They fled their tent in the middle of the night, cutting it open from the inside, and staggered outside into minus-30-degree-Fahrenheit temperatures. Weeks later, they were found in various stages of undress and with bizarre injuries. One hiker had bitten off part of his right hand.
Why would seasoned mountaineers behave so bizarrely? Grab your warmest detective’s hat. To solve this decades-old mystery, we’ll explore the harmful effects extreme cold has on the human body.
The Science Behind Extreme Cold
The human body works best at around 98.6 degrees Fahrenheit. Some people run a little hotter or colder, but generally homeostasis, or the body’s balancing of internal conditions, works to keep us at this temperature.
What happens when this internal balancing act fails? What happens if the human body is exposed to extreme cold — say, from getting lost in a snow storm like the Dyatlov Pass hikers or taking a plunge in freezing waters like the Titanic passengers?
The Hypothalamus: The Brain’s Thermostat
When the body senses a drop in temperature, the hypothalamus springs into action, triggering vasoconstriction: a process where blood vessels narrow, drawing blood away from extremities to protect vital organs and prevent ice crystals from forming in the blood. This reaction does leave extremities such as the hands, feet, nose, ears and lips vulnerable. As blood flow to the extremities slows, frostbite becomes a looming threat.
The Three Stages of Hypothermia
When our core temperature drops below 95 degrees Fahrenheit, hypothermia sets in, and the body begins an uphill battle where it can no longer replace heat at the rate it’s lost.
Mild Hypothermia: 89.6-95 Degrees Fahrenheit
The skin pales. The heart races. And the body starts to shiver, an involuntary tightening and relaxing of muscles that boosts the body’s surface heat production by 500%.
When core body temperature reaches between 91.4 and 93.2 degrees Fahrenheit, brain activity begins to decline, leading to irritability, confusion and poor decision-making. Mild hypothermia suffers may also feel sleepy, exhausted even. But falling asleep could mean never waking up again.
Moderate Hypothermia: 82.4-89.6 Degrees Fahrenheit
When core temperatures drop below 89.6 degrees Fahrenheit, shivering stops. It’s a red flag that the body’s heat regulation systems are failing. Below 86 degrees Fahrenheit, breathing and heart rate slows. Symptoms escalate:
- Slurred speech
- Hallucinations
- Muscle stiffness
- Dilated pupils
- Abnormal heart rhythm
- Loss of consciousness
Severe Hypothermia: Below 82.4 Degrees Fahrenheit
Most sufferers lose consciousness by this stage. Their heart rate and breathing slow to a crawl, and their lungs fill with fluid. At this stage, the heart or respiratory system will fail unless they receive immediate medical attention.
In the final stage of hypothermia, sufferers can feel sudden, extreme warmth as their blood vessels open in a last-ditch effort to warm tissue. Afraid, confused and burning up, sufferers have been known to strip off their clothes in a phenomenon known as “paradoxical undressing” — a fatal mistake in freezing conditions.
The Mystery of the Dyatlov Pass Incident Solved
The stages of hypothermia explain the baffling behavior of the Dyatlov Pass hikers. Modern research, including simulations using code from the animated movie “Frozen” (yes, really), suggests that the group was hit by a very small avalanche that forced them to abandon their tent.
Injured and disoriented, the surviving hikers sought shelter in the nearby forest. The winds reached sixty-five miles per hour. The temperature was around minus 30 degrees Fahrenheit, which is well below freezing.
And the hikers were barefoot.
They built a fire under a cedar tree, but soon faced hypothermia. And as their body temperatures dropped, delirium set in, which explains their bizarre behavior. One hiker burned himself trying to keep warm. Another had bitten his hand. The hikers succumbed not to aliens, weapons testing or a yeti attack, as has been speculated, but to the cold.
The Real Sufferers of Hypothermia
Every year, hypothermia claims as many as 1,500 lives in the U.S. While hypothermia is often associated with outdoor adventuring and wilderness expeditions, hypothermia sufferers are typically young children, elderly people, homeless people and people who abuse drugs or alcohol: anyone unable to control their own body temperature.
If tales like the Dyatlov Pass incident inspire you, you could always become a search-and-rescue volunteer, St. Bernard in tow. But there’s another, likely more effective way to save the lives of hypothermia sufferers.
Brave the Elements (of Medicine)
At the University of Florida, our online graduate programs are designed for aspiring medical professionals, especially those hoping to ace the MCAT, thrive in health-profession school and make a name for themselves in the world of medicine.
A Degree in Medical Physiology and Pharmacology Awaits
UF’s online master’s degree in medical physiology and pharmacology is one such program, providing foundational knowledge of the systems of the human body — the nervous, cardiovascular, respiratory system and more — and the medications that affect them.
Want to learn about medicine beyond niche facts about wilderness survival? Apply to UF and earn an online medical physiology degree that can help you build a rewarding career in medicine, one where your knowledge of the harmful effects of extreme cold on the human body could help you save lives.
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
