Torpor is a poorly understood physiological state

In 1923, Detlev Müller was a graduate student at the University of Copenhagen. As part of his magistere conference, an examination that was a requirement for his advanced degree, he had to give a presentation on February 3rd of that year.  As he began his presentation, he noted a  line of professors sat in the front row ready to question him, among them, perhaps the most famous Professor at the University,  August Krogh.  Professor Krogh had recently won the Nobel Prize in Physiology or Medicine (1921).  Detlev’s  presentation was probably on a mold or plant, the exact topic is lost to history.  But, after his presentation Professor Krogh approached Detlev and asked him to meet with him the next week because he had some laboratory work for him.

Professor Krogh assigned Detlev to administer insulin to mice.  Krogh was working, with Hagedorn, to isolate insulin from pig pancreases.  They needed an assay to test the potency of the insulin solution.  In Toronto and at Eli Lilly, Collip and the Eli Lilly team had developed an assay with rabbits.  The purity of each batch of insulin was gauged by the volume of that batch needed to induce a rabbit into hypoglycemic shock.  In Copenhagen, they had limited facilities and couldn’t keep an adequate number of rabbits on hand, so they chose to test the insulin in mice.

It took some time to troubleshoot the mouse assay.  At first, the mice did not exhibit the convulsions that characterized hypoglycemic shock in rabbits.  Instead the mice just curled up into a ball and went into a hibernation-like state, probably torpor.

Torpor is a poorly understood physiological state.  If laboratory mice are deprived of food and placed in an environment with a cool temperature, their normal body temperature and metabolic rate is reduced.  This reduced state is called torpor.

If torpor occurred in humans in the same way as in mice, a human in the state of torpor would have a body temperature of 10 degrees C and a heart rate of only 3 beats per minute.  Torpor can occur in daily pattern, or a seasonal pattern.

Several cases of a torpor-like state have been reported in humans.

Erika Nordby, 1 year old, 2001 wandered outside in Canada, -20 C, for several hours wearing only a t shirt.  Her mouth was frozen shut, no detectable heart beat.

1999, a 29 year old medical student Anna Bågenholm, was skiing with friends in the Kjølen mountains near the Norway/Sweden border.  As she sped across a mountain stream, she plunged into the water through a hole in the ice.  Her momentum carried her deep under the 8 inch thick ice.  She was trapped.  Her friends called for assistance, but it took 90 minutes for a rescue helicopter to reach them.  The rescue team brought her out of the ice.  She exhibited no signs of life. They airlifted her back to the University Hospital of North Norway in Tromso.  She arrived at the hospital over two hours after she had first entered the water.  At the hospital, her core temperature was 56 F.  They warmed her body up.  Four and a half hours after she first plunged under water, her heart was restarted.  It took her several months to fully recover, but she eventually did.

http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(00)01021-7/abstract

 

Mitsutaka Uchikoshi, a 35 year old office worker from Nishinomiya, Japan was attending a barbecue in a remote area amidst the Rokko mountains near Kobe.  Rather than join the other guests who were returning in a cable car, he decided to walk down the mountain.  On the way down, he fell and broke his pelvis. He was missing for 24 days.  It was October 2006, the weather was cold, but not extremely so.  It was averaged about 50F.  A hiker found him lying in a field and brought him to Kobe City General Hospital. He was treated for severe hypothermia.  His core body temperature was measured at 71F.  He recovered fully.

His recollection of the event is interesting.  He said that “on the second day, the sun was out, I was in a field, and I felt very comfortable.  That’s my last memory, I must have fallen asleep after that.