Cryonics comes from the Greek word kryos, meaning icy cold. Today, cryonics is the practice of lowering the body temperature of a person who is recently deceased or terminally ill to prevent the death and deterioration of living tissue. Even when a person is considered “clinically dead,” a majority of the cells in the body are still alive. The hope is that by freezing either the head or the whole body, the cells that are still alive can be preserved for an extended period of time. Advocates believe that in the future, when the technology becomes available to cure diseases, the body can be restored to health. For some, cryonic suspension is considered a realistic and feasible way of overcoming death.
It was the book The Prospect of Immortality by Robert C. W. Ettinger that spread the idea of cryonic suspension of a human being in the United States. Published originally in 1964 and revised in 1966, the book described Ettinger’s theories about life and death. In it, he states that “most of us now breathing have a good chance of physical life after death—a sober, scientific probability of revival and rejuvenation of our frozen bodies.” He believed that even if the techniques of today for freezing are rudimentary and flawed, given enough time, “sooner or later our friends of the future should be equal to the task of reviving and curing us.” In 1976, Ettinger helped establish and was subsequently elected president of Cryonics Institute in Clinton Township, Michigan. Known as the “father of cryonics,” he remained president until 2003.
The process for preserving a body is begun as shortly after death as possible. This is to reduce further tissue deterioration. The water within the body is replaced by a cryoprotectant that, when cooled to very low temperatures, hardens like glass. This is necessary because if a cryoprotectant were not used, the cells would burst: When water freezes, it expands and forms ice crystals that would damage or kill all of the cells. This process of converting cells to a crystalline-free solid is called vitrification and is the backbone of the cryonic suspension procedure. Vitrification can also be seen in nature. Some animals, like the wood frog, can survive days or weeks with up to half of their body water frozen. The liver in these frogs produces glycerol, which lowers the freezing point and reduces ice crystal formation, causing the water to harden like glass. Patients are generally frozen using liquid nitrogen at a temperature of -196° C. Liquid nitrogen is used because it lowers the temperature in a very short time. One important effect is that when water is frozen very quickly, it does not have time to form ice crystals. This, in addition to the use of cryoprotectants, preserves as many cells as possible.
The reason why freezing a body, or any living tissue for that matter, preserves it is that lowering the temperature decreases metabolism. Metabolism is the conversion of nutrients into energy. Within normal physiological temperatures, the body breaks down nutrients to acquire energy and sustain life. As temperatures lower, metabolism slows because the chemical and enzymatic reactions that use up energy occur less rapidly. Many animals, such as the frogs mentioned earlier, can survive long periods without food as a result of decreased energy consumption. The practice of lowering metabolism is not limited to lower forms of life. The ability of the bear to survive throughout an entire winter without food is due to its low metabolism while hibernating.
The first person to be cryonically frozen with the intent of future resuscitation was Dr. James Bedford, on January 12, 1967. The 73-year-old psychology professor was frozen by scientists from the Cryonics Society of California. Using dimethyl sulfoxide (DMSO), a primitive cryoprotectant, his body was frozen first with dry ice and then transferred to liquid nitrogen. Of the 17 people preserved between 1967 and 1973, Dr. Bedford is the only one still being cryopreserved. In 1982, he was moved to the Alcor Life Extension Foundation in Scottsdale, Arizona, where he remains today. Alcor currently has 77 cryonically preserved patients. The Cryonics Institute in Michigan cares for 84 patients and an additional 50 pets.
The cryonics movement progressed slowly and was generally rejected and dismissed by the general public. Since cryonic suspension had little scientific credibility, most in the scientific community did not support it either. For some, however, the idea that a body could be preserved for thousands of years was very alluring. Through the 1980s and 1990s, scientific developments in the fields of molecular nanotechnology, computer science, and mathematics made great strides toward overcoming the biological obstacles of cryonic suspension. For example, advancements in cryoprotectants made them more effective and less toxic. A more precise understanding of organ preservation also changed the way in which the body is cooled after death. In addition to lowering the body temperature before transport to a cryonics facility, where it will then be frozen, the body’s blood is first replaced with an organ-preserving solution. This solution is not a cryoprotectant. Its only purpose is to protect the organs from further cell death during transport. Prior to vitrification, it is replaced by a cryoprotectant at the cryonic facility. But for all the publicity and money spent on research, the successful freezing and thawing of a human being is not yet possible; it is the complicated thawing process that will take more time to perfect. Because the body is deceased when frozen, even if every living cell were to be resuscitated successfully, the body would still be “clinically dead.”
Although the successful cryonic suspension and resuscitation of a human being is still very far off, it is not irrational to maintain that someday the technology will exist to repair any cellular damage in the body. If all obstacles are overcome with time, then the possibilities for human beings could be endless. Not only could humans live an indeterminate life span on Earth, but a cryonically suspended body could travel to places in the universe millions of light years away, and the trip would be seemingly instantaneous to the traveler.
See also DNA; Dying and Death; Hibernation; Longevity; Medicine, History of
Ettinger, R. (1966). The prospect of immortality. New York: Macfadden-Bartell.
Kastenbaum, R. (1989). Encyclopedia of death (R. Kastenbaum & B. Kastenbaum, Ed.). Phoenix, AZ: Oryx.
Kurtzman, J., & Gordon, P. (1976). No more dying: The conquest of aging and the extension of human life. Los Angeles: J. P. Tarcher.
About cryonics. (n.d.). Cryonics Institute. Retrieved October 20, 2007, from www.cryonics.org/ reprise.html