Acclaimed author Jack London wrote a short story called To Build a Fire that follows an unnamed man making his way through deep snow in Alaska on a day that is at least 50 degrees below zero. He is described as a newcomer to the Yukon and is walking to a mining camp where friends are waiting for him with a tasty meal and warm fire. The camp is a 9-hour trek through ice and snow, and the man’s only companion is a native husky. He stops once to build a fire and eat a small lunch; the dog is reluctant to leave the warm fire, but accompanies him onward. Both dog and man fall through ice on a frozen creek and he stops again to build a fire to dry them out, this time under a spruce tree. While trying to pull branches off the tree, he manages to dump snow on the fire and in a series of heartbreaking errors is unable to get the fire started again. After a desperate attempt to reach the mining camp with numb hands and failing strength, he ultimately surrenders to the frozen land knowing that he should never have attempted this type of trip alone. The dog stays will him until his final breath, then continues on alone toward the mining camp, dinner and a warm fire. Unfortunately, only the husky gets a happy ending in this story.
There is no precise core temperature at which the human body perishes from cold. No one can predict exactly how quickly and in whom hypothermia will strike, and whether it will kill when it does. The cold remains a mystery. So how does death by freezing occur?
As soon as the bitter cold air hits your face, your body will try to insulate itself by moving blood away from the skin and outer extremities toward the core in a process known as vasoconstriction. The second response is shivering; major shivering doesn’t occur unless your core body temperature drops. For example, at 97 degrees your neck and shoulders tighten in something called pre-shivering muscle tone, and your hands and feet may begin to ache with the cold. By the time your core body temperature reaches 95 degrees, your body has mild hypothermia and you are trembling violently as your body reaches its maximum shivering response, which is an involuntary condition in which the muscles contract regularly to generate additional body heat.
With every 1 degree drop in body temperature below 95, the enzymes in your brain become less efficient. In minus-35-degree air for example, your core temperature falls approximately 1 degree every 30 to 40 minutes. Somewhere between 93 degrees and 91 degrees, amnesia sets in and you will remember little of what happens after that. At about 89 degrees, stupor sets in as well as visual and auditory hallucinations, and by 82 degrees you will lose consciousness. This is about the time that profound hypothermia arrives (ICD-10-CM codes T68.XXXA, X31.XXXA); deserted by their leader (the brain), the rest of the organs begin shutting down.
Your body may experience thickening blood, low oxygen consumption, arrhythmia and an abandonment of the need to shiver. Your kidneys, however, continue to work overtime to eliminate the fluid overload created when fluids were shunted from your extremities to your core, and you may involuntarily urinate. If there is no intervention, the heart will stop trying to pump blood, the internal processes will come to a halt and brain tissue will begin to perish.
On May 20, 1999, Dr. Anna Bagenholm was 29-years-old and skiing on a favorite trail outside Narvik, Norway with two friends who were also young doctors. It was a beautiful day and the conditions were great, but a few runs into the outing Bagenholm tripped, slid and fell head first into a frozen stream and was trapped between ice and rocks. As her companions held onto her feet and called for help on a mobile phone, she first found an air pocket to breathe, then was weighed down by her wet clothes and succumbed to unconsciousness.
When rescue arrived, Bagenholm had been submerged for 80 minutes, she had no pulse, her blood was not circulating, her skin was ghost white and her pupils were dilated. The emergency team started CPR until a helicopter arrived and she began the hour-long flight back to Tromso University Hospital where her body temperature was measured at 56.7 degrees Fahrenheit, nearly 42 degrees below normal. No one had ever been that cold and survived. It was there that over 100 doctors and nurses worked over 9 hours to bring Bagenholm gradually back to life.
However, the fight had just begun: she woke up after 12 days, paralyzed and with her kidneys and digestive systems failing. She spent 2 full months in the intensive care unit, and another 4 months in a rehabilitation unit before returning home. The good news is she suffered no brain damage, although she has no memory of the accident. The residual nerve damage prevents the normal use of her hands, so her original plan to pursue a career in orthopedics was shelved. As a radiologist with Tromso University Hospital, she now reads MRIs and CT scans, checks on patients and completes rounds.
As Elizabeth Edwards once said, “You recognize a survivor when you see one. You recognize a fighter when you see one.” Even as the icy water had stopped her heart, it had preserved her brain. And so, thanks to the glacial conditions that might have killed her, Dr. Anna Bagenholm made medical history; she did not freeze to death – she just temporarily froze.