There are three different stages of hypothermia, each of which is characterized by a distinct set of symptoms. Mild hypothermia is the least severe of these stages, with the other two being known as moderate and severe hypothermia. The symptoms of mild hypothermia may be vague or otherwise difficult to spot, but generally include shivering, mental confusion, and an abnormally high heart rate. Hypothermia typically occurs when the core body temperature drops below 95°F (35°C), and is the result of the body not being able to replenish the heat that is lost when it is exposed to cold temperatures. Mild hypothermia may also be induced following certain ischemic events such as cardiac arrest, stroke, or traumatic injury to the brain or spinal cord.
A healthy human body is typically able to maintain its core temperature somewhere between 98 and 100°F (36.5 and 37.5°C) through the biological processes of homeostasis and thermal regulation. Prolonged exposure to extreme cold can overcome the body's ability to replenish heat as it is lost, which can be compounded by alcohol consumption, dehydration, wet clothing, and other factors. When this happens the core body temperature can drop to the point where normal metabolism and other body functions become impaired, and mild hypothermia sets in. A person suffering from mild hypothermia may shiver, suffer from an elevated heart rate, show signs of mental confusion, or exhibit other similar symptoms. Typically, if the person in question is able to stop shivering voluntarily, they have not progressed beyond mild hypothermia.
The mild form of this condition may not be immediately life-threatening, but the more severe stages can be. When suffering from mild hypothermia, it is important to deal with the situation before it progresses to a moderate or severe form. Some simple kinds of hypothermia first aid can involve reducing heat loss, dealing with dehydration, and adding more heat to the body. A reduction in the loss of body heat can be done by removing wet clothing, adding additional layers of apparel or blankets, and increasing physical activity, while adding heat can involve the use of any external heat source, including simple body-to-body contact. Dehydration is also important to deal with, as lack of fluids can exacerbate hypothermia.
Therapeutic hypothermia is a form of induced mild hypothermia that can help reduce the risk of tissue damage after certain ischemic events. An ischemic event is any time that blood flow is reduced to any part of the body, and can be the result of stroke, cardiac arrest, or a number of other things. By lowering the core body temperature, the risk of tissue damage from these type of events is lowered. Either invasive or non-invasive procedures can be used to induce hypothermia in these cases. Invasive measures typically involve the insertion of a catheter into the femoral vein, into which a cooled saline solution may be circulated. Non-invasive methods may include wrapping the torso or extremities with blankets through which cooled water is circulated.
