Recent advances with the use of hydrogen sulfide, carbon monoxide and “hibernation induction triggers” to depress metabolism in animal models have renewed interest in the possibility of human hibernation. The ability to drastically depress human metabolism without the use of cold (or in combination with cold) would have a number of important medical and scientific applications including the stabilization of trauma patients, prolonging the time of safe circulatory arrest in surgery, and space travel.
In 2007, the author published a review of the field of depressed metabolism for Alcor’s Cryonics Magazine and expressed skepticism about the prospect of real hibernation in humans any time soon. But this does not mean that we cannot learn from natural hibernators to identify metabolic pathways that can be inhibited to prolong the period the brain can sustain circulatory arrest at normothermic and hypothermic temperatures. As evidenced by the remarkable period myocardium can sustain energy deprivation and still recover, there is still a lot about human metabolism that remains obscure.
Like many ideas in biogerontology, the idea of chemically manipulating human metabolism as a medical procedure to prolong or save lives has gone through various cycles of optimism and disillusion. In his 1969 book Suspended Animation, the author Robert Prehoda presented a number of proposals to manipulate metabolism in humans. Another person who wrote about depressed metabolism, or “human anabiosis,” was the cryobiologist Armand Karow (1941-2007). During the year 1967 Karow wrote a 5 part series on the science and prospect of depressed metabolism in humans for Cryonics Reports which is made available for this first time online. Although Karow devotes most of his series to the technical obstacles to achieve real suspended animation using cryogenic temperatures, he also discusses the use of metabolic inhibitors to protect vulnerable organs during cooldown to cryogenic temperatures.