If there were ever a time to hibernate, now would be just dandy. Coincidentally, researchers have been exploring the mechanisms behind human hibernation for decades now — and they appear to be nearing a breakthrough. “Hibernation works by a regulated suppression of metabolism that allows animals to survive periods of no or limited food,” explains hibernation researcher Kelly Drew. “Hibernation is all about energy conservation. Once we understand how hibernating animals regulate their metabolism, we should be able to achieve the same thing in humans. Shutting down the metabolism can be useful for critical care and maybe one day even for long-term space flight.”
Science may change your mind.
How would human hibernation even work?
Well, as Drew mentioned, we still have a lot to learn about the ins and outs of hibernation. However, a medical treatment called therapeutic hypothermia, which involves using ice packs and cooling blankets to temporarily lower the body temperature of patients, has been considered for its ability to replicate a hibernation-like state in humans. “In hospital settings, they’ll cool down a patient who had a stroke or a traumatic brain injury to lower their metabolism for a couple days,” says John Bradford, president and CTO of SpaceWorks Enterprises, where he researches human hibernation. “It gives the body time to recover.” More specifically, therapeutic hypothermia allows the brain and other organs to survive for longer while deprived of oxygen from the heart.
There are also some proposed pharmacological approaches to human hibernation that seem especially promising, such as adenosine receptor agonists. “They’re like the opposite of caffeine, and they build up in your body naturally,” says Bradford. “That’s why you get tired.” Researchers already know that activating the adenosine A1 receptors induces hibernation in rats, so we may very well be able to extend this process to humans.
And how exactly would hibernation help with space travel?
In many ways! For one, if we can extend the human lifespan by hibernating — a slower metabolism generally means a longer life — we can travel much further into space. Though, that may still be a long ways away.
But Bradford is currently looking into how hibernation could help us with basic interplanetary travel — say, from Earth to Mars. “It allows you to put the crew in a much smaller habitat, because they’re not as active all the time,” he says. “It also reduces the amount of food that they need and oxygen demand.” As an added bonus, being asleep staves off the boredom of floating through space for weeks and months on end, which again means less cargo.
Furthermore, Bradford says research shows that hibernation may also provide some protection against radiation, which is a unique challenge during space travel and would allow for more innovation in the world of spacecraft design (radiation shielding currently takes up quite a lot of space on rockets). “Lowering your metabolism may also mitigate some of the muscle atrophy and bone loss that you often experience during space flight,” he adds.
Are there any concerns?
During space travel, hibernating astronauts would need to be fed through a tube, since our bodies aren’t equipped to store food reserves. There are also some worries about how prolonged low body temperatures may impact the brain — research in bats shows that most memories are preserved even after many months, but some seem to be better protected than others. However, for these reasons, Bradford has his sights on starting with shorter bouts of hibernation, like only two weeks at a time, until we know more. Even being able to hibernate for a week would be a huge success, though.
When can we start hibernating, then?
Bradford says sending hibernating astronauts to Mars is still a ways off, but sending them to the moon could happen in the next few years, and he suspects humans will start applying learnings from hibernation research to processes like organ transplantation and even basic wellness sometime soon. “Within our genes, we have the capability to hibernate,” he emphasizes. “Some people probably would have appreciated the ability to just go to sleep for a couple weeks during these COVID times.”
In fact, just last month, the Translational Research Institute for Space Health held a seminar that dug into “the potential use of synthetic torpor for long-term human space exploration,” among other things (Drew was one of the speakers in attendance). So scientists are clearly making headway.
I’ll have my pajamas ready.
And I’ll be prepared to kiss my friends goodnight before they enter their extended sleep.