Hypothermia

The cooling of the body core results in hypothermia. It can happen in a matter of minutes, if you fall into cold water. Or it can creep up on you over a matter of hours or days. Everything depends on the conditions that promote lowering the body core temperature. There are five mechanisms responsible for loss of core warmth. Most of them can be controlled by you.

• Conduction — If your flesh touches an object that is colder than your body temperature, heat will transfer from your body to the cold object. The rule is to not let anything except the soles of your shoes or boots touch the cold ground. Don't sit on a cold rock or a damp log. Don't lie on the cold ground without plenty of thermal insulation beneath you. 
• Convection — The movement of air around your warm body will steal away the heat. Protect yourself from even the slightest breeze. 
• Evaporation — When moisture evaporates, cooling takes place. If your clothes are wet, the evaporation process will act like an air conditioner around your body. If your skin is wet, you will lost core warmth as the water evaporates.
• Respiration — With every breath, you exhale warmth that comes from your body core and ends up outside. With every breath, you inhale cold air that chills your body core. You must breathe, but you don't have to breathe cold air. Inhale from inside your jacket. Exhaling into your clothing will capture moisture in the fabric, so it's better to exhale into the surrounding air. 
• Elimination — There is a reason urine and solid waste release steam when it hits the ground on a cold day. Warmth is leaving your body via the elimination process. Not much you can do about this. 

It doesn't take exposure to extreme cold for hypothermia to claim a victim. The gradual loss of core warmth can happen to swimmers in 80-degree tropical water. Or it can happen inside a house when the heat has been shut off for a prolonged period. The elderly, the very young, and those who are weakened by illness are particularly at risk. The instruments of death by hypothermia are:

• Damp body or clothing
• Fatigue
• Insufficient nourishment
• Being chilled
• Exposure to the wind

To protect against hypothermia:

• Stay dry
• Eat warm high-calorie meals regularly
• Drink warm beverages (non-alcoholic, because alcohol promotes hypothermia)
• Protect yourself from exposure to the wind
• Wrap up to hold your body core warmth - cover your head, neck, wrists (an emergency blanket will reflect your body warmth back toward you
• Snuggle with someone who is warm, or wrap up in a blanket together with a fire-warmed stone (wrapped in a cloth to prevent burns)
• Exercise mildly to generate body warmth