Simply put, hypothermia happens when the body loses heat faster than it can generate it. If the body loses too much heat and can’t be brought back to normal, the results could be fatal.
Body heat can be generated by the body in a few ways:
- Drinking warm fluids
- Exercising such as walking, running, or shivering
- Heating elements such as hot pads or heated jackets
Not all heat loss is bad, however. There may be times when you may be overheating from wearing too many layers. It’s important to layer properly.
The body loses heat in 4 different ways:
Radiation – Radiation is electromagnetic energy in infrared wavelengths. The human body is emitting and receiving this type of energy. This is also the same type of energy the sun emits. About 60% of heat loss from the body is because of radiation.
Conduction – Conduction happens when you come in physical direct contact with something cold. Heat is transferred from your warm body to the cold object. Ice, snow, water and wet clothing are examples of objects that can steal your body heat.
Convection – Convection is when heat that is around the body, such as inside a warm jacket, is stolen by the wind.
Evaporation – Evaporation through sweat requires energy to turn moisture and turn it into a gas. Evaporation also happens when breathing. Warm moist air is exhaled, and cold dry air is inhaled, which results in heat loss.
Stages of Hypothermia
Early Stages: In early stages of hypothermia, the body temperature is roughly between 98.6 to 95.0 degrees Fahrenheit. Signs include intense shivering and inability to control muscular coordination. The person may feel cold, tired, and confused.
Middle Stages: Body temperature has dropped into the 95.0 – 90.0 temperature range. The person will continue to shiver violently. The person experiences difficulty in speaking, thinking, and walking. Judgment is impaired and they may experience amnesia and hallucinations. Apathy and sometimes lack of awareness about their situation sets in.
Late Middle Stages:Â Body temperature continues to drop into the 90.0 to 86.0 temperature range. The person has stopped shivering and is unable to rewarm themselves. The can no longer walk or speak. Their muscles are rigid, their skin has turned blue (cyanotic), and their pulse and respiration visibly slow down. The person is nearing unconsciousness.
Late Â Stages: The person’s body temperature is now around 86.0 to 78.0, and they become unconscious. They are nonresponsive and their pulse and respiration may not be noticeable. Any further decline in body temperature below 78.0 can result in death from heart and respiratory failure.
Early Detection and Hypothermia Prevention
Avoiding hypothermia is about being prepared, practicing winter safety, and being aware of each other and your environment, especially on the trail.
Here are a few ways to stay prepared and avoid hypothermia:
- Wear proper clothing
- Put on proper clothing before it rains or snows, and take off clothing before you overheat and sweat.
- Protect yourself from the wind.
- Pace yourself accordingly. Working at 60% will burn fat reserves instead of glucose and glycogen stores.
- Avoid tight clothing. Clothing and footwear that is too tight will prevent blood circulation.
- Get enough sleep and rest
- Eat and drink well, especially calorie dense foods and carbohydrates throughout the day.
- Don’t push too hard. Rest and sleep well.
Be aware of yourself and other members of the team. Don’t be afraid to stop and turn around if there is a dangerous situation.
Treatment of Hypothermia
As soon as it becomes apparent that someone on the team is hypothermic, stop and check the rest of the group. If one person is hypothermic, there is a good chance that other members of the team are hypothermic as wellStop and set up camp immediately. Like with ice and avalanche rescue, emergency situations must be practiced in advanced so that everyone can react quickly and efficiently in a real emergencyÂ situation. Set up the tents, build a fire, light the stoves, and heat up warm liquids. Meanwhile, someone must stay with victims at all times and take charge of the situation.
Stop and set up camp immediately. Like with ice and avalanche rescue, emergency situations must be practiced in advanced so that everyone can react quickly and efficiently in a real emergencyÂ situation. Set up the tents, build a fire, light the stoves, and heat up warm liquids. Meanwhile, someone must stay with victims at all times and take charge of the situation.
Those in the early stages of hypothermia must get warm immediately. Give them food and fluids. Make sure they are out of any wet clothes and into dry clothes. Place the person near a heat source, such as a fire or another person. Putting the victim in a sleeping bag with a warm person will work as a reheating strategy, but only if the warm person is wearing dry and light clothing. It’s not good for the rescuer to be naked, as they will perspire and chill the victim.
If the victim is in middle or later stages of hypothermia and unable to warm themselves, more active measures must be taken. The victim should be handled gently with care, in a controlled and protected environment, such as a tent. External heat sources must be provided and heat loss must be stopped.
The first step during this stage is to insulate the victim from the cold ground. This can be done with sleeping pads, extra clothing, pine bought, or anything else on hand. Next, place heat packs or water bottles filled with warm water at the victim’s neck, groin, and underarms. The heat packs and water bottles should not be too hot to the touch. If they are too hot, wrap them in underwear or gloves.
Place the victim in a prewarmed sleeping bag. Then, wrap him in a tarp, tent fly, reflective blanket, or other windproof and waterproof material, to prevent further heat loss. If the victim isÂ able, he could sip very sweet liquids to allow the sugars to replace the energy reserves that were spent during shivering. If the victim is not able to sip liquids themselves, do not force them onto the victim.
If the victim becomes unconscious or does not show any sign of vital activity, continue treatment and prepare for evacuation. If you must move the victim, be extremely gentle. Even though the victim may show no signs of vital activity, the heart still may be operating at a very low level. Any rough handling could cause the heart to stop.