Third of a five-part series about low body temperature.

by James Hubbard, M.D., M.P.H.

In part one of this series about low body temperature, I gave a scenario about staying out in the cold a little too long and becoming nauseous.

In the story, the person thinks the problem is an empty stomach. But he’d better watch out. The first symptoms of a low body temperature are often hunger, nausea, and fatigue. Pretty general. And the next thing you know, you’re getting confused.

If you’re mentally impaired by drugs, alcohol, disease, or other reasons, you may not even notice there’s a problem. So if it’s below 50 degrees, or you or someone else has other risk factors for low body temperature, be on the watch for symptoms.

Symptoms of Mild Hypothermia

Hypothermia is defined as a body temperature below 95 degrees F or 35 degrees C. At that point it’s called mild. Your body’s still trying to generate heat, and you:

  • Shiver
  • Have trouble talking
  • Can get confused
  • Have deteriorating judgment
  • Can develop amnesia
  • Have a sped-up heart rate

Symptoms of Moderate Hypothermia

When your body temperature gets under 90 degrees (32 degrees C), you have moderate hypothermia, and you:

  • Stop shivering
  • Get more confused
  • May start taking off clothes. (It’s called paradoxical undressing. No one’s sure exactly why this happens, except we know the body’s temperature regulators are going haywire. See scenario two in part one of this series.)
  • Have a slowed heart rate that may become irregular
  • Are at risk to develop lethal heart rhythms

Symptoms of Severe Hypothermia

At 82 degrees (28 C), the hypothermia is severe, and you:

  • Are likely to go into a coma
  • Are at great risk to develop a fatal heart rhythm (ventricular fibrillation)
Miraculous Recoveries in the Cold

People have been known to survive freezing temperatures even if they’ve stopped breathing for a time. When this happens in conjunction with a cold-water drowning, it’s called the dive reflex. You can read more about that at my general-health website written by health-care professionals,

As you can see, you better recognize the symptoms of low body temperature early. A couple of potential pitfalls when trying to do that:

  • If the person has other medical problems, you might think the symptoms, such as confusion, are from the other disease (example: low blood sugar from diabetes). Solution: Treat both–the low body temperature and the other problem.
  • If the person is comatose or his or her heart has stopped, you may not be able to tell if the low body temperature is the primary problem or the person’s heart has stopped from, say, a heart attack or head trauma. Solution: Perform CPR. Providers who treat people with hypothermia have a saying,: “No one is dead until they’re warm and dead.” Miraculous recoveries do occur, and rarely, people survive longer when they have a low body temperature than they would otherwise. But each instance is unique. Don’t endanger yourself from the cold or fatigue. There’s another saying: “Sometimes, no matter what you do, people die.”

In my next post, I’ll go over how to treat low body temperature.

Five-Part Hypothermia Series:

  1. Low body temperature: How cold is too cold?
  2. Risk factors for hypothermia (besides cold weather)
  3. (This post) Symptoms of hypothermia
  4. Hypothermia treatment, part one: How to treat a conscious person
  5. Hypothermia treatment, part two: How to treat an unconscious person