Can Humans Be Frozen and Revived? The Science Behind Cryonics & Suspended Animation

Imagine attending a funeral, mourning the loss of someone dear. Years later, you take a quiet walk in the park, and there they are. Standing. Breathing. Alive. Do you run, screaming in shock? Do you question reality, believing you’re seeing a ghost? Or do you stand frozen, unable to comprehend the impossible?

It begins with a moment of heartbreak.

A loved one, slipping away. The final embrace, the whispered farewell, the unbearable permanence of loss. But what if death wasn’t final? What if it was merely a problem of timing?

What if, instead of being lost to time, they could be paused – preserved in a frozen stillness, waiting for a future where medicine could heal them?

For decades, the idea of cryonics and suspended animation has danced between science fiction and reality. The notion that death could be delayed indefinitely, that a person frozen today might be revived in a world centuries ahead, has fascinated scientists and futurists alike.

But how close are we?

The answer might not be as far away as we think. Nature has already done it. Some animals survive freezing temperatures without harm. Medicine has done it. People have been revived after hours of clinical death, thanks to extreme cold. And now, scientists are pushing the boundaries of what’s possible- exploring whether human life can be put on pause indefinitely.

This is the story of a radical idea – a scientific frontier that challenges the limits of biology, technology, and even ethics. A journey filled with unexpected discoveries, bold scientific gambles, and questions that redefine life itself.

Could we really freeze people and bring them back?

And if we can, should we?

Lessons from the Frozen: When Humans Cheat Death

Can humans survive extreme freezing conditions?

To understand whether freezing humans for the future is possible, we don’t need to look to the future. We only need to examine accidental survivors – people who have already been frozen and revived.

One of the most famous cases is that of Anna Bågenholm, a Swedish radiologist who, in 1999, fell into an icy stream while skiing. She was trapped under the ice for 80 minutes, her body temperature plummeting to a near-lethal 56°F (13°C) – more than 40 degrees below normal human temperature. Her heart stopped.

By all medical definitions, she was dead.

But Anna wasn’t truly gone. The extreme cold slowed her metabolism so dramatically that her brain and organs shut down before permanent damage could occur. When doctors gradually rewarmed her blood in a controlled manner, her body restarted.

She survived.

Anna’s case is not unique. Across the world, people have been revived after hours of clinical death due to accidental hypothermia. This suggests that, under the right conditions, human life can be paused and restarted.

“A frozen body might lie around for years in a ‘dead’ condition, then all at once come alive, without any physical change whatever, as soon as someone found a means of resuscitation.”

Robert Ettinger

But could we extend that pause from hours to decades? That’s the challenge cryonics and suspended animation researchers are trying to solve.

Cryonics: The Dream of Freezing for the Future

What is cryonics, and how does it work?

In 1962, physicist Robert Ettinger presented an idea that stunned the scientific world.

In his book, The Prospect of Immortality, he made a bold claim:

1. Freeze the body at extremely low temperatures to prevent decay.
2. Wait for future medicine to repair any damage and revive the person.

Ettinger believed that death wasn’t final – it was simply a failure of current technology. He argued that if we could cool the body fast enough, before decomposition set in, revival could become a future medical procedure – just like CPR or organ transplants today.

His ideas launched the modern cryonics movement, and today, over 300 cryonics patients are stored in liquid nitrogen at −196°C (-320°F) at facilities like Alcor and the Cryonics Institute, waiting for a future where revival might be possible.

The Biological Barrier: Why Freezing Is So Dangerous

But the greatest challenge in cryonics technology isn’t the freezing – it’s the damage caused by ice.

Water expands when frozen, forming sharp ice crystals that tear cell membranes apart, destroying tissues beyond repair. If a human body were frozen using traditional methods, it would be shredded at a microscopic level.

The Breakthrough: Vitrification – Freezing Without Ice

To overcome this, cryonics researchers use vitrification – a process that replaces water in cells with cryoprotectants (antifreeze chemicals). This prevents ice from forming, allowing tissues to be cooled to ultra-low temperatures without crystallization.

How Does Vitrification Work?

In biological systems, water is a crucial component of cells, and when tissues are frozen, the water inside the cells typically forms ice crystals. These ice crystals can rupture cell membranes and damage internal structures, including proteins and DNA, often leading to cell death. In vitrification, the cryoprotectants are introduced into tissues before freezing. These substances essentially replace the water in the cells and prevent the formation of ice crystals during the cooling process. As a result, instead of freezing, the tissue undergoes a process of glass-like solidification.

“At very low temperatures it is possible, right now, to preserve dead people with essentially no deterioration, indefinitely.”

Robert Ettinger

This technique has already been used to preserve embryos, corneas, and organs. And in 2016, scientists successfully vitrified and revived a rabbit’s brain – intact, with its synaptic structure preserved.

The result? A brain that had been frozen and thawed, its connections seemingly untouched.

It was a crucial step toward proving that memory, personality, and consciousness might survive cryonic freezing.

But despite these advancements, there’s one major problem – no mammal has ever been revived from full-body cryonic freezing.

Cryonics offers hope. But what if there was another way?

Suspended Animation: The Science of Pausing Life

What is suspended animation, and how is it different from cryonics?

Instead of stopping biological functions altogether, what if we could reduce metabolism to near zero, allowing people to hibernate for months, even years – only to wake up without harm?

This is the promise of suspended animation, and scientists are already testing it in humans.

Mark Roth’s Game-Changing Discovery

In 2005, biologist Mark Roth discovered that exposing mice to hydrogen sulfide (H₂S) caused their metabolism to drop by 90%. Their body temperature dropped, and their oxygen needs disappeared – yet they remained alive.

Hours later, they were revived with no signs of damage.

For the first time, researchers had paused life without freezing.

How Suspended Animation is Already Saving Lives

Inspired by Roth’s work, trauma doctors are now using Emergency Preservation and Resuscitation (EPR), a technique where critically injured patients are cooled to 50°F (10°C) to delay death, giving doctors extra time to perform life-saving surgery.

“It is possible, although not certain, that the greater part of the damage occurs in thawing and not in freezing; hence these patients, after freezing, need not be considered dead, and their condition could be called ‘suspended animation.”

Mark Roth

At the University of Maryland, this technique is already being tested in gunshot and stabbing victims.

If we can suspend life for hours, could we extend it to decades?

Would You Take the Risk?

For now, the frozen bodies in cryonics labs remain silent time capsules, waiting for a future that may never come. But with each new discovery, the dream of pausing time itself moves closer to reality.

If given the chance, would you choose to be frozen today, hoping to wake up in a better future?

Would the future be a utopia – or a lonely, alien world where everything you once knew is gone?

Would you take the risk?