Hypothermia, or a very low body temperature, can be life-threatening. Even with proper care of patients admitted to the hospital with hypothermia, the mortality rate can still be quite significant.

What leads to hypothermia?

Excessive or prolonged exposure to cold is a very common cause of hypothermia. While this serious condition can usually be prevented, it is important to realize that many cases of hypothermia are not simply due to being outside in extremely cold weather for a long time. A person can develop hypothermia in her own home as she sleeps or even as she goes about her regular daily routine. In this time of economic hardship, many people may find themselves unable to heat their homes or they may turn their thermostats down very low to save on energy bills. Remember to protect yourself and now allow yourself to become too cold. (Please see signs of hypothermia below.)

In addition to cold exposure, other things can precipitate hypothermia. For instance, an under-active thyroid gland can lead to hypothermia, as can an under-active adrenal gland, a severe infection, thiamine deficiency, a low blood sugar, and even malnutrition, to name a few common conditions.

Even some medications can contribute to hypothermia, such as some oral anti-diabetic medications, high blood medications, including beta-blockers, and some medications that treat anxiety or depression. Of course, all such drugs do not cause hypothermia and even those that do cause a low body temperature do not do so in all individuals or at a level that is usually of any major clinical significance.

What is the definition of hypothermia?

Hypothermia is defined clinically as a core body temperature of less than 35 degrees Celsius (or 95 degrees Fahrenheit).

Mild hypothermia is a core body temperature ranging from 32-35 degrees Celsius (90-95 degrees Fahrenheit).

Moderate hypothermia is a core body temperature ranging from 28–32 degrees Celsius (82-90 degrees Fahrenheit).

Severe hypothermia is a core body temperature of less than 28 degrees Celsius (82 degrees Fahrenheit).

How does hypothermia damage the body?

The body's cells are altered by fluxes in body temperature. For instance, the membranes that surround the cells themselves are impacted by cold temperature. Cells can ultimately die as a result of damage to their membranes. The cellular proteins malfunction and the water within cells can literally crystallize.

The brain tries to counteract a cold challenge by stimulating heat production, such as through shivering and other mechanisms, but if the cold temperature is severe or sustained, the body's protective mechanisms may not be powerful enough to overcome the stress.

What are some signs of hypothermia?

The following are some of the major symptoms that may be seen with hypothermia of differing degrees. However, it is important to realize that the lack of any of these symptoms does not rule out hypothermia. Likewise, the presence of these symptoms does not confirm a person has hypothermia.

Mild hypothermia:
Rapid respiratory rate and heart rate
Poor judgment
Shivering
Incoordination
Incoherent speech

Moderate hypothermia:
Low respiratory rate and decreased heart rate
Lack of shivering

Severe hypothermia:
Low blood pressure and heart rate
Shortness of breath due to fluid collecting in the lungs, also known as pulmonary edema
Potentially fatal heart rhythms

The winter months can be beautiful, but they can also be deadly. Take all appropriate precautions to protect yourself from hypothermia.