Human Hibernation

There is a report from Japan of a 35 year old man who became separated from his climbing party on Mount Rokko and was lost for 23 days. He is said to have been found with a core temperature of 71 degrees Fahrenheit, and to have been resuscitated and then doctored/nursed back to his normal pre-hypothermic condition, at least with regard to brain functioin. That he survived at all has been cited by some as a miracle, indeed, to perhaps represent an episode of "human hibernation." Is this possible?

We know that hypothermia creates a physiological situation that has been likened to a "metabolic icebox," in that the requirements for energy are greatly lessened in comparison to what is needed by someone for normal-temperature biological activities. When a person has a markedly lowered body temperature, he or she doesn't need as much oxygen (so can survive with a lower rate of breathing), sugar supply to the brain and other vital organs (so can supply with a lower heart rate and blood pressure), and so forth. So, in some sense, hypothermia can be protective, so long as its deleterious effects, such as tissue damage (frostbite), abnormal heart rhythms (which can be fatal), and other ill effects do not predominate.

What we know about Mitsutaka Uchikoshi, the climber in question, is that he separated from his friends and was found 23 days later, hypothermic, but not damaged so badly that he couldn't fully recover. He claims to have been unconscious for 20 or 21 days, but does that mean that this is actually what happened? Perhaps he wandered for many days in a confused state from moderately severe hypothermia before he actually lapsed into unconsciousness. Perhaps he was only truly severely hypothermic for a brief period of time.

The reports support the fact that he was severely hypothermic, but the true duration of his period of hypothermia is not fully known. As has been noted by at least one other observer, it is easy to hypothesize how he might have survived a period of 23 days without food, but surviving that period without any water is less plausible. However, as we know from Aron Ralston and others who have excellent documentation for feats of human endurance that would have not been survived by others, there are many exceptions to our accepted notions. Perhaps this is such a case.

Tags: hibernation, hypothermia, wilderness medicine, outdoor medicine, healthline

photo by Mathias Schar

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