Hypothermia happens when the body loses heat faster than it can make it, causing core temperature to drop below the safe range. It can occur in freezing weather, but it can also happen in cool, wet, or windy conditions. Students who hike, camp, play outdoor sports, or travel in winter should know the warning signs.
Recognizing hypothermia early can prevent confusion, collapse, and life-threatening injury.
The body first tries to protect itself by shivering and narrowing blood vessels near the skin to keep warm blood around vital organs. As cooling continues, the brain and muscles work more slowly, so a person may stumble, speak unclearly, or make poor decisions. Severe hypothermia can make shivering stop, which is a dangerous sign rather than an improvement.
The safest response is to get the person out of cold, remove wet clothing, add dry insulation, warm the body gradually, and call for emergency help if symptoms are serious.
Key Facts
- Normal core body temperature is about 37°C or 98.6°F.
- Hypothermia begins when core temperature drops below 35°C or 95°F.
- Cold water removes body heat much faster than cold air, so wet clothing greatly increases risk.
- Early signs include shivering, cold skin, numb fingers, clumsiness, and tiredness.
- Worsening signs include confusion, slurred speech, loss of coordination, slow breathing, and weak pulse.
- Basic response steps are move to shelter, remove wet clothing, insulate with dry layers, warm the center of the body, and call emergency services for severe symptoms.
Vocabulary
- Hypothermia
- A dangerous condition in which the body's core temperature falls below 35°C or 95°F.
- Core temperature
- The internal temperature of the body's vital organs, especially the brain, heart, and lungs.
- Shivering
- Rapid muscle contractions that help the body produce heat when it is too cold.
- Wind chill
- The increased cooling effect on the body caused by moving air carrying heat away from the skin.
- Insulation
- Material such as dry clothing, blankets, or sleeping bags that slows heat loss from the body.
Common Mistakes to Avoid
- Assuming hypothermia only happens below freezing is wrong because wind, rain, sweat, and cold water can cause dangerous heat loss even above 0°C.
- Thinking stopped shivering means the person is getting better is wrong because shivering may stop in severe hypothermia when the body is losing the ability to warm itself.
- Rubbing cold hands, feet, or skin hard is wrong because it can damage tissue and may move cold blood toward the body core too quickly.
- Giving alcohol to warm someone up is wrong because alcohol widens blood vessels, increases heat loss, and can make judgment and coordination worse.
Practice Questions
- 1 A hiker's temperature is measured at 34.4°C after hiking in wet clothing. Is this below the hypothermia threshold, and by how many degrees Celsius?
- 2 A student begins a trip with a body temperature of 37.0°C. After exposure to cold wind and rain, the student's temperature drops to 35.2°C. How much did the temperature drop, and how close is it to the 35.0°C hypothermia threshold?
- 3 A cold hiker is no longer shivering, is confused, and has slurred speech. Explain why this should be treated as an emergency even if the hiker says they feel fine.