Whether as a means of traveling through deep space, a life-saving measure, or a process of slow time travel, placing humans in suspended animation is a well-worn trope in genre fiction. Futurama, Star Trek, and the Fallout games all prominently utilize some form of suspended animation as a plot device, but never has the concept of freezing one's self and waking up in the future been more ridiculously utilized than in 2006’s Idiocracy.
In it, U.S. Army Corporal Joe Bauers (Luke Wilson) follows in the famed footsteps of Phillip J. Fry, Khan Noonien Singh, and Han Solo, on an unintentional trip to the future. Flawed as the premise may be, suspended animation is an ongoing area of research and may one day assist in medical treatments and long-term space travel.
THE CASE FOR SUSPENDED ANIMATION
There are plenty of sci-fi tropes that stretch the bounds of credulity. Time travel, teleportation, invisibility — all potentially possible with sufficiently advanced technology, but not something we see a lot of empirical evidence for in the real world. At least not on the macro-scale. Suspended animation, however, is downright commonplace if you know where to look.
Rotifers, a collection of relatively simple microscopic animals, are common to freshwater environs all over the world. They feed on algae and dead bacteria, among other things, and are often preyed upon by the more famous tardigrade. These entirely female species reproduce asexually and have a lot of the same incredible abilities as tardigrades, namely the ability to survive in harsh environments.
In the event their watery home dries up, rotifers undergo anhydrobiosis, a process that involves contract into themselves and slowing their metabolism, perhaps even halting it altogether. In this state, rotifers and similar creatures lay in waiting for suitable conditions to return.
In the normal course of events, the waiting period should be relatively short, a few days or months, maybe a season. There have been documented cases of anhydrobiosis lasting for several years, but those instances pale in comparison to a recent discovery published in the journal Current Biology.
A team of researchers, studying permafrost in Siberia, recovered bdelloid rotifers from ice core samples dating back approximately 24,000 years. The researchers clarified that not all rotifers survive such extended deep freezes. In fact, only 1 in 20 or fewer samples result in successful reanimation. Still, those who do survive are able to exit their anhydrobiosis stage and even reproduce — a happy result of that asexual reproduction mentioned above.
The way in which small animals like rotifers and tardigrades accomplish these incredible levels of suspension aren’t wholly understood, but part of the process seems to involve the manufacturing of antifreeze-like chemicals which prevent the formation of ice crystals in their tissues. Understanding precisely how that unfolds could unlock an avenue for human cryonics.
Other animals, more complex than the humble rotifer, undergo different types of suspended animation which are nonetheless equally intriguing.
Hummingbirds have a staggeringly high metabolism, requiring near-constant consumption of nectar in order to survive. Their heart rates are so fast they sound less like the rat-a-tat drumbeat we’re used to and more like an incessant buzzing. It’s difficult to imagine an animal more diametrically opposed to the concept of suspended animation, and yet, in the Andes mountains of Peru, these fast-flying birds have adapted to slow down. At least at night.
Many birds, and other animals, enter a state known as torpor when necessary. Similar to hibernation, torpor allows an animal to severely decrease its metabolism in order to wait out lean times. For black metaltail hummingbirds, the lean times come every night when temperatures drop.
As night falls and temperatures decrease, these birds decrease their body temperatures to just above freezing, and their heart rates, usually thrumming at 1,200 beats per minute, decrease to as low as 40.
The common theme, whether you are a rotifer or a hummingbird is the slowing down of metabolism, decreasing the body’s energy needs until you can return to a more active state. Achieving such a state in humans has thus far proven difficult. Though there are some promising areas of research.
WHAT ABOUT US?
The human body is capable of at least temporary suspended animation, under the right conditions. We know this because it has happened, accidentally. The trouble is figuring out how to make it happen reliably.
Emergency preservation and resuscitation (EPR) has shown some promise in extending treatment timeframes in pigs, which are often used as a stand-in for humans in medical research. The process involves pumping ice-cold saline solution into the aorta, dramatically reducing body temperature to approximately 50 degrees Fahrenheit.
At this temperature, brain and body activity slows, buying doctors time to treat injuries. A small clinical trial began at the University of Maryland’s Shock Trauma Center, targeting patients with acute trauma and a low estimated chance of recovery. The aim is to extend the critical treatment window from minutes to hours. At the time of this writing, the results of that study are not available.
This process of freezing might be useful as a last-ditch treatment option or for those willing to throw in their chips on a chance at being resurrected in the future, but isn’t being seriously considered by space agencies as a method of deep space travel. Instead, both NASA and ESA are exploring torpor as a potential solution.
Vladyslav Vyazovskiy is part of the team put together by ESA to answer this question. He suggests there’s probably no biological barrier to human torpor, given that the process spans all types of mammals including primates.
Success in this area will require a more robust understanding of the precise mechanisms in place when animals enter and exit torpor. Today, we don’t know what’s happening biologically to induce this state, or what the potential impacts might be on humans. Finding answers to these questions could provide significant advancements in both medical treatments and the future of space exploration.
Research is ongoing, and with any luck, we might one day be able to nap through the hard times. What a world it could be. Hopefully, it'll be a smarter world than the one we see in Idiocracy.