by Sean Murphy
The human body is not designed for extreme cold which is why humanity has inhabited parts of the world with warmer climates what rarely go below zero. Despite some areas of the world being inhabited thanks to communities adapting to their climate, we generally avoid cold conditions.
If you’ve experienced sub zero temperatures that go beyond minus zero, for example -20C degrees you would know how debilitating this could be and the effects on the human body. So cold you can feel your muscles seize up and even simple acts like talking or moving your arms feel completely impossible. The term “freezing to death” becomes an actuality.
As adventurers, we put ourselves in situations where we go into cold climates and poor preparation could literally become a case of life or death. A sudden drop in temperature increases blood pressure so placing more strain on your heart, your body also works harder to generate more heat when it’s cold.
Illnesses can be induced by cold conditions including influenza, and asthmatics are normally the first to be targeted as breathing becomes increasingly difficult the longer they are exposed. Nothing triggers an asthma attack like continuously inhaling cold air, just as allergic reactions to dust or pollens might. But there are worse ailments you can become vulnerable to than the influenza and asthma.
In extreme cold, the human body has several defence mechanisms to try and boost our core temperature. Our muscles shiver and teeth chatter and we get goose bumps. The hypothalamus, the gland in the brain that acts as your body’s thermostat, stimulates these reactions to keep the body’s vital organs warm. It then becomes a matter of survival.
Hypothermia is where the body’s core temperature falls from what it should be at 37C to 35C. If the loss of heat continues, the body will slow it’s metabolism to minimise it’s need for fresh blood flow and the need for oxygen. If oxygen level drop there is a risk of organ failure and organs need oxygen to continue functioning.
When the temperature reaches sub-zero or more, skin has to be kept away from the elements in order to prevent frost nip and frostbite. Frost nip occurs when a part of your body becomes so cold that the blood is slowed down because that area is losing too much heat and the human body has chosen to sacrifice that area. The nose, ears, cheeks, toes and fingers are generally the first affected and can be identified by the skin becoming an un-natural pale colour due to the lack of blood flow.
Frost bite occurs when weak blood flow to exposed flesh causes tissue damage. Ice crystals actually form inside body cells, killing them in the process which makes recovery impossible. In the most severe cases, limbs and extremities have to be amputated.
To prevent any of the above, but still enjoy your adventure in a freezing climate, do your research into where you are going. Be part of a group and carry the appropriate gear, clothing and first aid kits. Have signalling and communication devices for emergencies if you become separated from your fellow adventurers. Know your body limits and know when to increase your layers.