Hypothermia is the lowering of the body’s core temperature; brain and muscle function become impaired. You may recognize the signs and symptoms of hypothermia in your friends, but your body has no mechanism to recognize hypothermia in yourself. You can slip down the hypothermia continuum without realizing you are getting dangerously cold. Your body is reacting to losing more heat than it can produce.
In treating hypothermia it is important to know two things: how your body loses heat, and how it produces heat.
How we lose heat:
- Conduction – heat loss through contact with a cold surface
- Convection – heat loss through movement of wind or water. You lose heat 25x faster in water!
- Radiation – involves the transfer of heat from one object to another, with no physical contact involved. (think of the radiator in your house)
- Evaporation – the process of losing heat through the conversion of water to gas (evaporation of sweat)
How we produce heat:
- Metabolism – burning calories for fuel
- Exercise – muscle contraction produces heat
- Behavior – putting on clothing will help conserve heat
The first thing that happens is vasoconstriction. Your brain stops blood flow to the extremities to decrease heat loss. Your hands and feet get cold, you may start to shiver. Shivering creates warmth through involuntary muscle contractions. Metabolism increases by burning glucose to produce heat.
The hypothermia continuum: (adapted from the SOLO Wilderness First Aid book)
- 98.6F – Normal
- 97F – Judgment fails, you don’t take care of yourself. You may not put on the extra coat or hat.
- 96F – Constant shivering begins. You can’t physically zip your coat or put on your gloves.
- 94F – You shiver harder. You may get the “umbles” … stumble, fumble, tumble, crumble. Coordination is failing
- 92F – Shivering is intense, you can’t walk
- 90F – Shivering is convulsive, you are in the fetal position and cannot speak
- 86F and below – You are unconscious, ashen grey, you may appear dead (no pulse or chest rise). This is known as “The Metabolic Icebox of Doom”
Treatment for hypothermia (how do we produce heat?)
- Movement – Do jumping jacks, run in circles. Get those muscles moving
- Eat simple quick burning carbohydrates. (some people like to drink jell-o dissolved in hot water)
- Put on dry warm clothing
- Find or build a shelter
- Make a hypothermia wrap aka burrito roll
Do not give anything orally if the person is unconscious.
Burrito roll construction: (think about layering for warmth, Dress for Success)
- The base layer is made of a waterproof/windproof layer such as a tarp
- The first insulating layer (laid directly on the tarp) is typically made of a sleeping pad. Anything that can break the conductive heat loss from the ground
- On top of the pad lots of dry insulation such as sleeping bag, blankets, emergency blankets, extra clothing
- Place the patient in the insulation. Cover head with a hat, take off boots and protect feet
- Wrap securely
Before you head out do your homework. Ask yourself the following questions:
- What is the long range weather forecast?
- How long will you be out and what will you be doing? Snowmobiling? Snowshoeing? Skiing? Ice fishing?
- Do you have appropriate clothing ? Dress for Success
- Do you have the proper equipment? First Aid Kit? Shelter? Extra Layers? Fire Starter? Communication device?
- Do you have enough food (quick burn carbohydrates)? Hot drinks?
- Are you friends prepared?
- Do you know the signs and symptoms of hypothermia?
- Do you know how to treat someone who is hypothermic?
- Do your friends or family back home know where you are going?
Practice making burrito rolls with your friends prior to going out. It is fun, simple and you are learning a very useful skill. Remember you can slip into hypothermia without knowing it is happening. Dress properly, eat carbohydrates, drink water or an electrolyte drink, watch each other and have an awesome time exploring.