Thermoregulation is an ability that not only humans, but nearly all animals and plants, possess. It is the process by which an organism keeps its body within a certain temperature range, even when the temperature outside its body is very different. Thermoregulation is important to organisms because the bodies of plants and animals function best at specific temperature ranges, and if body temperature slips too far outside its ideal temperature range, the organism will die.
For humans, the ideal body temperature is 37 degrees Celsius, or 98.6 degrees Fahrenheit. Humans can function normally when their body temperature is between the range of 36.5 and 37.5 degrees Celsius, or 97.7 to 99.5 degrees Fahrenheit. Any colder and your body will start shivering uncontrollably, your muscles will tighten to an uncomfortable extent, and you will have very low energy. Too low and you will get hypothermia and freeze to death. If your body gets any warmer than the ideal temperature range, you will start sweating heavily, if you’re hydrated enough, and you will become dizzy and feel overwhelmingly fatigued. If you get too hot, you will get hyperthermia, and overheat to the point of death.
This is why it’s very important to remember thermoregulation while outdoors, especially in a survival situation. If you are lost, your ultimate goal should of course be to be rescued, but if you want to be found alive, helping your body with the process of thermoregulation is of vital importance. If you’re wandering in the Canadian Rockies in the middle of the winter and you begin to shiver uncontrollably – take a key from your body and immediately look for shelter, build a fire, or find some other way of getting your core body temperature up. If you’re in the Arizona desert and you begin to feel exceptionally dizzy, go hide in the nearest shade possible, or soak your clothing in some water if you’re fortunate enough to be near any, because your body needs a break from the heavy heat of the sun.
In a survival situation, you should absolutely always be taking steps to prevent yourself from developing hypothermia and/or hyperthermia: from the very start. You shouldn’t wait until you start to violently shiver to check if you have gloves in your pocket and put them on. Waiting until your body is showing symptoms of hypothermia or hyperthermia can sometimes be too late. This is why survival experts will at times recommend things like traveling at night instead of during the day in very hot temperatures. Of course, always balance thermoregulation against other safety precautions: if predators have a better chance of catching you at night because human vision is terrible at night and you wouldn’t be able to spot them in time to back away, it’s probably wiser to stick to travelling under the heat in daylight. That being said, if there are no serious disadvantages to doing something beneficial to maintaining your body’s thermoregulation, certainly plan ahead and take precautions in order to prevent yourself from developing, or even dying of, hypothermia or hyperthermia.