Hypothermia commonly occurs during the winter and in cool, damp conditions. It can lead to serious injury, illness or even death.

You have likely experienced hypothermia before, but you may not have realized it. When you shiver in response to the cold, your body is attempting to maintain a normal body temperature of 98.6 F. That’s hypothermia.

The following table illustrates how your body reacts to increasingly cold conditions.

Core Body TemperatureYour Body’s Reaction
98.6 FYou feel normal.
95 FYour body begins to shiver (mild hypothermia).
92 FYour body stops shivering, your reaction time slows, your metabolism slows and your thought process slows (moderate hypothermia).
88 FYou become sluggish, your skin appears pale or ashen, your metabolism slows and you feel fatigued (severe hypothermia).
85 FYou feel extremely sluggish and may lose consciousness.

Watch out for signs of hypothermia

At 92 F, your body stops shivering. As your core temperature drops, your heart and breathing rates slow and your blood pressure drops. Your pulse becomes irregular, indicating your heart cannot supply oxygenated blood to your body.

Hypothermia can affect your performance without you knowing it, even in an ambient air temperature of 55 F.

A sample scenario

Here's an example of a situation that could easily lead to hypothermia:

You’re out hunting. It’s 4 a.m. and cold outside, so you’re bundled up.

By 9 a.m., you are sweating and your clothes are wet from perspiration. By 11 a.m., it’s drizzling and the outer layer of your clothes is soaked. The temperature drops a couple of degrees and it starts to get windy.

As the wind blows, your clothes begin to wick heat from your body and the heated moisture from your clothing evaporates. Your body temperature begins to drop, causing you to shiver and your teeth to chatter.

At 4 p.m., the sun begins to set and the temperature drops quickly. You notice you’ve stopped shivering, even though you’re still in the woods. Your clothes are wet. You feel fatigued. You sit down to rest and realize you can’t remember where you parked your car. You feel disoriented. As the sun goes down, you realize you’re in trouble.

Hypothermia at work

If you work outside, hypothermia can also happen on the job. You come to work dressed appropriately, but physical exertion causes you to sweat, and your clothes get wet. As the moisture from your clothing evaporates, your body gets colder. Your energy level decreases and you lose focus. Now you’re primed for an injury.

If you don’t know the signs or causes of hypothermia, you might not realize you’re in trouble. So how do you protect yourself?

How to prevent hypothermia

  • Wear layered clothing that you can add or remove as the temperature fluctuates. For your first layer (against the skin), choose a material made from wool, silk, bamboo or synthetic fibers that wick sweat away from your body. Then add a cotton shirt, followed by an insulating material like wool. Do not choose cotton for your outer layer, since even wet wool is a better insulator than dry cotton. Avoid coveralls, as you can't easily remove them if you get hot or your clothing gets wet.
  • Drink plenty of water. Water keeps your cells hydrated and working properly. Breathing alone expels moisture from your body, in addition to sweating.
  • Avoid alcohol. Alcohol is a depressant, which can cause vital body functions to slow. The cold decreases your metabolism, and alcohol makes that worse. Alcohol also dehydrates you, so it will not replace lost body fluids.
  • Drink warm fluids in moderation. Choose caffeine-free teas, hot chocolate or hot water with lemon. Drinking warm fluids will help you maintain a body temperature of 98.6 F.
  • Take short, frequent breaks in warmer environments like an office or a heated vehicle, or in front of heat-generating equipment.
  • Keep a change of clothing in case your clothes get wet.

What to do if you experience hypothermia

If you experience hypothermia:

  • Remove any wet clothing.
  • Put on clean, dry clothes.
  • Get to an external heat source, such as a blanket or heater.
  • If possible, place your clothing in a dryer or near a heat source to preheat it before putting it on. (A word of caution: Never place anything on a heat-generating device or interfere with air circulation around the device. This could cause a fire or malfunction.)
  • Drink a warm beverage.
  • Apply a warm compress, but not to your extremities. Heating your arms and legs can force cold blood back to your heart, lungs and brain. Also avoid heating pads and heat lamps, as direct heat can cause an irregular heartbeat.

While you can’t control the weather, you can reduce your risk of hypothermia by educating yourself, dressing appropriately and being prepared. Taking precautions now can save you from a life-threatening situation in the future.