We need a constant temperature of around 37°C to work properly. To do this, our bodies adjust to changes in the climate in two ways:
Behavioural – this refers to conscious reactions like putting on more clothes or moving around.
Physiological – this refers to automatic (involuntary) reactions like changing the blood circulation, shivering or sweating.
Cold hands and feet are your body’s way of telling you you’re getting cold. You body is trying to conserve heat in your vital organs and so it reduces blood flow to your extremities. But if you don’t take heed of this early warning, frostbite could take hold.
Sweating is a normal reaction when your body is overheated and in warm climates it helps maintain that just-right core temperature of 37°C. But in cold climates it can be dangerous and is another potential cause of frostbite.
Speaking of sweating, water conducts heat 25-30 times better than air and rapidly transports energy away from your body. So sweat, snow and water can also lead to cold-related health problems like hypothermia.
Another warning sign is shivering. These uncontrolled muscle contractions are your body’s method of generating heat. But too much shivering makes normal muscle function difficult and if things deteriorate hypothermia might set in.
So what is hypothermia exactly? It’s when your body’s core temperature is lower than normal. The onset of hypothermia can begin when your core temperature drops to below 35°C. This doesn’t sound like much, but at this point your body will start to shiver and shake and you’ll begin to lose your ability to think rationally. If this continues, the shaking will slowly disappear and be replaced by apathy and you won’t be able to take care of yourself. Advanced hypothermia is when your body temperature falls below 30°C. Then you lose consciousness. At this point it’s hard to tell if you’re breathing or if you have a pulse.
This is when the temperature of a specific body part falls to below 37°C. It affects exposed parts of the body first, that are furthest from the core such as cheeks, nose, fingers and toes. Superficial frostbite is characterized by cold, white skin and small sharp pains followed by loss of sensation and, left to develop, it can increase the risk of hypothermia. If superficial frostbite spreads, it can result in long-term damage to your body’s tissue.
The most important thing is to ensure you eat and drink enough, stay dry and adapt to the changing weather by adding or removing clothing. Find our more about dressing for the cold here. Keep an eye on each other. Cold related illnesses are often hard to detect in yourself. Look out for skin discolouration, excessive shivering, irrational actions and apathy in your fellow Polar adventurers.
Start by seeking protection from the elements – wind, rain, snow – in the forest. And make sure you keep moving. Walking in deep snow is a good way to warm up. If possible, add another layer of clothing and drink something warm and sweet. Warm the frostbitten body part slowly until sensation, colour and mobility return – this usually takes about 20-30 minutes. Don’t ever rub the skin. Instead, heat skin against skin. Frozen cheeks can be warmed using your hands. Frozen hands can be warmed in your own armpits and frozen feet can be warmed in a friend’s armpits.