How Cryonics Works

Cryogenic storage containers. See more cryonics pictures.

­The year is 1967. A British secret agent has been "frozen," awaiting the day when his arch nemesis will return from his own deep freeze to once again threaten the world. That day finally arrives in 1997. The agent is revived after 30 years on ice, and he saves the world from imminent destruction.

You'll probably recognize this scenario from the hit movie, "Austin Powers: International Man of Mystery" (1997). Cryonics also shows up in films like "Vanilla Sky" (2001), "Sleeper" (1973) and "2001: A Space Odyssey" (1968). But is it pure Hollywood fiction, or can people r­eally be fr­ozen and then thawed to live on years later?

­The science behind the idea does exist. It's called cryogenics -- the study of what happens to materials at really low temperatures. Cryonics -- the technique used to stor­e human bodies at extremely low temperatures with the hope of one day reviving them -- is being performed today, but the technology is still in its infancy.

In this article, we'll look at the practice of cryonics, learn how it's done and find out whether humans really can be brought back from the deep freeze.

What Is Cryonics?

In an operating room at Alcor Life Extension Foundation, a cryonics patient is cooled in a vat of dry ice as part of the "freezing" procedure.
In an operating room at Alcor Life Extension Foundation, a cryonics patient is cooled in a vat of dry ice as part of the "freezing" procedure.

­Cryonics is the practice of preserving human bodies in extremely cold temperatures with the hope of reviving them sometime in the future. The idea is that, if some­one has "died" from a disease that is incurable today, he or she can be "frozen" and then revived in the future when a cure has been discovered. A person preserved this way is said to be in cryonic suspension.

To understand the technology behind cryonics, think about the news stories you've heard of people who have fallen into an icy lake and have been submerged for up to an hour in the frigid water before being rescued. The ones who survived did so because the icy water put their body into a sort of suspended animation, slowing down their metabolism and brain function to the point where they needed almost no oxygen.

Cryonics is a bit different from being resuscitated after falling into an icy lake, though. First of all, it's illegal to perform cryonic suspension on someone who is still alive. People who undergo this procedure must first be pronounced legally dead -- that is, their heart must have stopped beating. But if they're dead, how can they ever be revived? According to scientists who perform cryonics, "legally dead" is not the same as "totally dead." Total death, they say, is the point at which all brain function ceases. Legal death occurs when the heart has stopped beating, but some cellular brain function remains. Cryonics preserves the little cell function that remains so that, theoretically, the person can be resuscitated in the future.

How Is Cryonics Performed?

Operating room at Alcor Life Extension Foundation
Operating room at Alcor Life Extension Foundation

­If ­you decide to have yourself placed in cryonic suspension, what happens to you? Well, first, you have to join a cryonics facility and pay an annual membership fee (in the area of $400 a year). Then, when your heart stops beating and you are pronounced "legally dead," an emergency response team from the facility springs into action. The team stabilizes your body, supplying your brain with enough oxygen and blood to preserve minimal function until you can be transported to the suspension facility. Your body is packed in ice and injected with heparin (an anticoagulant) to prevent your blood from clotting during the trip. A medical team awaits the arrival of your body at the cryonics facility.

Once you are transported to the cryonics facility, the actual "freezing" begins. Cryonics facilities can't simply put their patients into a vat of liquid nitrogen, because the water inside their cells would freeze. When water freezes, it expands -- this would cause the cells to simply shatter. The cryonics team must first remove the water from your cells and replace it with a glycerol-based chemical mixture called a cryoprotectant -- a sort of human antifreeze. The goal is to protect the organs and tissues from forming ice crystals at extremely low temperatures. This process, called vitrification (deep cooling without freezing), puts the cells into a state of suspended animation.

A surgeon at Alcor performs initial procedures to gain access to a patient's vascular system, preparing for the vitrification process.
A computer displays parameters such as temperature, flow rate and pressure during the four-hour vitrification procedure.

Once the water in your body is replaced with the cryoprotectant, your body is cooled on a bed of dry ice until it reaches -130 C (-202 F), completing the vitrification process. The next step is to insert your body into an individual container that is then placed into a large metal tank filled with liquid nitrogen at a temperature of around -196 degrees Celsius (-320 degrees Fahrenheit). Your body is stored head down, so if there were ever a leak in the tank, your brain would stay immersed in the freezing liquid.

Cryonics isn't cheap -- it can cost up to $150,000 to have your whole body preserved. But for the more frugal futurists, a mere $50,000 will preserve your brain for perpetuity -- an option known as neurosuspension. Hopefully for those who have been preserved this way, technology will come up with a way to clone or regenerate the rest of the body.

Following vitrification, patients are placed in individual aluminum containers.
Each aluminum container is placed in a "neuropod" or "wholebody pod" that is then immersed in liquid nitrogen. This neuropod is being lowered into position among four wholebody pods in a storage tank.

If you opt for cryonic suspension, expect to have some company. Several bodies and/or heads are often stored together in the same liquid-nitrogen-filled tank.

This container is designed to hold four wholebody patients and six neuropatients immersed in liquid nitrogen at -196 degrees Celsius. Liquid nitrogen is added periodically to replace the small amount that evaporates.

Has Anyone Been Preserved Using Cryonics?

­Doz­ens of people are being stored in cryonic facilities. Probably the most famous of them is baseball legend Ted Williams (see below). But no one has actually been revived, because the technology to do so still does not exist.

Critics say companies that perform cryonics are simply bilking people out of their money with the promise of an immortality they cannot deliver. Even scientists who perform cryonics say they haven't successfully revived anyone -- and don't expect to be able to do so in the near future. One of the problems is that, if the warming process isn't done at exactly the right speed, the cells could turn to ice and shatter.

Even though people in cryonic suspension haven't yet been revived, living organisms can be -- and have been -- brought back from a dead or near-dead state. Defibrillators and CPR bring accident and heart attack victims back from the dead on an almost daily basis. Neurosurgeons often cool patients' bodies so they can operate on aneurysms -- enlarged blood vessels in the brain -- without damaging or rupturing them. Human embryos that are frozen in fertility clinics, defrosted and implanted in a mother's uterus grow into perfectly normal human beings.

Cryobiologists are hopeful that a new technology called nanotechnology will make revival a reality someday. Nanotechnology uses microscopic machines to manipulate single atoms -- the tiniest units of an organism -- to build or repair virtually anything, including human cells and tissues. The hope is that, one day, nanotechnology will repair not only the cellular damage caused by the freezing process, but also the damage caused by aging and disease. Some cryobiologists predict that the first cryonic revival might occur somewhere around the year 2040.

The History of Cryonics

Dr. James Bedford
Dr. James Bedford

­The first person to be cryogenically frozen was a 73-year-old psychologist, Dr. James Bedford, wh­o was suspended in 1967. His body is reportedly still in good condition at Alcor Life Extension Foundation.

The idea that a person could be frozen and then brought back to life when the technology had evolved far enough originated with the book "The Prospect of Immortality," written by physics teacher Robert Ettinger in 1964. The word "cryonics" is derived from the Greek term for "cold."

By the late 1970s, there were about six cryonics companies in the United States. But to preserve and then maintain each body indefinitely was so expensive, many of these companies wound up closing shop by the following decade.

Today, only a handful of companies offer full cryosuspension services, including Alcor Life Extension Foundation in Arizona and the Cryonics Institute in Michigan. In early 2004, Alcor had more than 650 members and 59 patients in cryopreservation.

For more information on cryonics and related topics, check out the links on the next page.

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More Great Links


  • "The Prospect of Immortality" by R.C. W Ettinger
  • "Medical-Legal Aspects of Cryonics: Prospects for Immortality" by George Patrick Smith
  • "Forever for All: Moral Philosophy, Cryonics, and the Scientific Prospects for Immortality" by R. Michael Perry
  • "Cryonics: Frozen for Eternity" by George Stromeyer
  • "Cryonics: Reaching for Tomorrow" by Brian Wowk