Most people know that the normal temperature of the human body is 98.6 degrees Fahrenheit, or 37 degrees Celsius. But many of us don’t properly understand what it takes for our bodies to maintain this constant temperature. To survive in a cold climate when you are out in the wild, it helps to understand how the body loses heat.
Heat is produced by metabolism of food. If you’re hungry, you will not be able to create as much heat as when you stay well fed. When it’s cold out, you need to eat more food to stay warm and satisfied, because your body uses more energy just to maintain body temperature. And when you aren’t able to just stop by the grocery store for a snack, this form of heat regulation is a whole different challenge.
Anytime the temperature of your environment is lower than the temperature of your body, you will be losing heat and your body will be working to keep your body temperature at a normal level. While most of us can avoid hypothermia because we’re not out in the wild for long periods of time, and we can go home when we want to, it is not uncommon for even the most experienced hikers and backpackers do underestimate the importance of staying warm, sometimes when it is too late.
Learning About Heat Loss
We lose heat through conduction, convection, evaporation, radiation, and respiration. You can’t avoid respiration, also known as breathing, so you will always lose a little bit of heat in that way when you are out in the cold. But there are things you can do to avoid the other four ways you lose body heat.
Evaporative heat loss is what occurs when the wetness in your clothing evaporates, drawing heat away from your body. Waterproof clothing is critical, but so is ventilation and avoiding sweating by staying cool to begin with – which may seem counterintuitive. If your clothing gets sweaty and you have spares, change into your dry clothes before you get cold.
Conduction and Convection
These are two fancy words for pretty simple concepts. Conduction refers to the way heat is transferred from you to cold surfaces you are touching. If you sleep on the ground without enough padding, you will conduct heat to the ground much more quickly than if you increase the padding.
Convection refers to the way that warm air rises and moves away from you. If you wear the right clothing, you will be trapping the air you have warmed with your body instead of letting it get away.
Heat radiates away from your body the way that a campfire radiates heat. Radiation is the least of your worries, because it takes a very cold environment to cause you to radiate a dangerous amount of heat – well below zero.
Finding ways to stay dry, keep your body warm, and avoid transferring heat away from you are all very important. Knowing what to wear, what to do when you are cold, and how to avoid getting cold can save your life.