Exposure is the single biggest cause of death for people stranded in the wild, and it all comes down to the factor of temperature. Out of all the things that can happen to a person while out in the wilderness, the single biggest cause of death is officially exposure, but the initial cause can be different. For example someone could be stuck somewhere due to a physical injury, and so would die from exposure but “because” of the injury.
Apart from getting torn to pieces by a bear or dying from some horrible jungle infection, it all comes down to temperature, so here’s a few examples of how easy it is to die from the elements.
Cold Weather with Regular clothing (jeans, t-shirt and jumper/hoodie)
0°C with no wind
It would take a person about 2 days to die in these conditions, depending on the individuals body fat content. The individual would experience frostbite and hypothermia before then, but it would be mild enough to not actually be able to kill a normal sized adult. If someone fell asleep in these conditions then you can shorten the time to about 24 hours, as sleeping raises the body temperature slightly and would cause the core temperature to drop faster.
0°C with 10mph wind
The wind will make the air temperature feel as though its around -15°C as the cold air particles smash into the person and blow away any air that’s been heated by the body. Wind also helps to push cold air through clothing and can make it feel much colder than it actually is. In these conditions you would last around 12 hours until your body developed hypothermia serious enough to kill you if you fell asleep or passed out.
-20°C in a 20mph blizzard
When snow or sleet enter the game things start to get colder much faster. The moisture will melt slightly when it touches clothing but when it becomes a liquid it freezes faster than the body can melt it. If someone is completely soaked in -20°C air temperature they will die in less than 20 minutes, so your measly hoodie and jeans will add on no more than 30 minutes maximum before you pass out, giving a total life expectancy in these condtions of less than 1 hour.
-50°C with no wind
In regular clothing you’d be dead pretty fast, even without wind. This is the temperature you’ll find on a casual day in the middle of Antarctica, so don’t expect to be alive more than 15 minutes, and if the wind starts to blow faster than 30mph you can expect that number to be less than 5.
Hot weather with regular clothing
Since body temperature is 37°C it takes anything hotter than that to kill someone, unless factors such as humidity are added to the equation. Overheating causes a condition called hypothermia which can effectively partially “cook” vital sections of the body, particularly the brain cells and liver. Your body can remove excess heat by sweating, but if the humidity is high enough this wont have much of an effect.
45°C with 50% humidity
It would take the average adult about 6 hours to succumb to hypothermia at this temperature, but you would pass out before you actually died. It would also depend on how much water you had to drink as these temperatures would require you to drink water faster than you felt you needed to.
65°C with 10% humidity and 5mph wind
At this temperature you would last under 2 hours, providing the wind didn’t stop and you had unlimited water. If the humidity was as high as 50% in these temperatures then you can expect to be dead in less than 30 minutes.
Some commonly asked questions about temperature related conditions:
What is Hyperthermia?
Effects: Dizziness, increased heart rate, fainting, cramps, headaches
This condition is when the bodies core temperature raises above the 37°C average and causes various effects such as dehydration and the slowing of vital organs. If the core temperature is high enough then it can kill cells within the body and the first ones to go are from the kidneys and brain. The actual cause of death will most likely be the shutting down of the brain from losing to many cells rather than dehydration.
What is Hypothermia?
Effects: slowed heart rate, slowed breathing, tiredness, intense shivering
This is were the bodies core temperature goes below 35°C which causes the internal organs to slow down. Breathing and moving around become increasingly difficult and the more severe it gets the sleepier someone will become. People who die of the cold always fall asleep before they do, normally passing out from exhaustion or dying when they fall asleep naturally. The actual cause of death is normally the heart stopping, as it slows down as the temperature of the body decreases until it eventually stops.
What is Frostbite?
Effects: Decreased or no movement, change of skin tone, lack of feeling.
Frostbite is when the skin freezes, with the severity of it being judged on how deep the freezing has gone. When living tissue freezes it expands due to the moisture within it, and when cells expand enough their walls will rupture and the cell will die, putting it in a state of which it cant be healed again.
If a part of your body freezes down to the lowest layers of muscle then you’ll most likely lose the limb. If something partially freezes there’s a chance it can be brought back again so long as there’s enough living cells within the affected area to repair itself.
What is Frostnip?
Effects: Lack of feeling, pain, lack of movement
Frostnip is the first stage of frostbite, but in a mild enough way so that only the first layer or two of skin freezes and the affected area is in no danger of dying completely. When skin freezes on a shallow enough level there’s a very high chance that it hasn’t frozen entirely, as if it had the under-laying area would also be affected.
When someone has been affected by frostnip all they have to do is stop it from getting colder and developing into frostbite. If they can do that they will most likely make a full recovery and not lose so much as a finger nail, though it can be quite painful to thaw out a partially frozen finger.