Hypothermia is a sudden and dangerous drop in one's body temperature that happens due to prolonged exposure to cold temperatures or environments. The average human body temperature is 98.6 degrees, but those suffering from hypothermia can have their temperatures drop below 95 degrees, with severe cases recording temperatures as low as 86 degrees.

There is always a balance between the heat production of the body and heat loss, but when the balance tilts towards the heat loss, hypothermia occurs.

Many times it occurs because people are caught unawares either by the sudden drops in temperatures, or because they hadn't prepared themselves with enough warm and dry clothing to protect them from the cold. This is why professional mountain climbers wear specialized hypothermic gear for the cold and windy environment of mountains. When exposed to cold temperatures, up to 90% of the body's heat is lost through the skin, which happens mostly due to radiation, and increases rapidly when exposed to winds or moisture. The remaining escapes through your lungs. In such cases, the hypothalamus (which controls the body temperature in the brain) works hard in order to increase the body's temperature via various activities. For example, shivering is the body's natural protective response to increase heat. There is another way, called vasoconstriction, where the blood vessels narrow temporarily, thus preserving heat in the body. Under normal circumstance, the liver and heart produce the maximum amount of heat for the body. But with the cooling down of body temperatures, they produce less and less heat, causing a 'shut down' to protect whatever little heat is left for the brain to use. Hence, low temperatures can slow down breathing, heart rate and brain functions. Other symptoms include:

Losing consciousness
Shallow breathing
Confusion or memory loss
Unable to make proper, intelligent decisions
Numbing of hands and/or feet
Drowsiness
Exhaustion
Shivering
Reddish skin (in infants)

It is not always extreme cold that leads to hypothermia. Sometimes, it can be milder environments and factors which can trigger it. One has to take into account the person's age, medical history, body fat and period of time they were exposed to cold temperatures. For example, an elderly lady might develop mild hypothermia in a matter of hours if she is not seated next to a warm fire, blowers or heaters. It's the same with babies. Medical conditions such as diabetes, thyroid, severe trauma and reactions from drugs and even alcohol can increase the risk of hypothermia.

What should one do in case of Hypothermia?

You should first of all wrap the person in warm clothes or a blanket and bring them inside. Change their clothing, if need be. Do not immediately immerse them in warm water or place them in front of a blower because sudden warming of the body can lead to arrhythmia. Wrap hot water bottles in a cloth first and then apply it on the skin.