What's the longest you've ever slept?

The weather outside is frightful, but the fire is so delightful… …So why not crawl up beside it and go to sleep until the seasons change?

That’s what Russian peasants once did when food was scarce. For 6 frigid months, they would wake only once a day to consume a small portion of bread and ale, before going back to sleep.

Last century, it was called “lotska.” Today, we’re calling it human hibernation. And we’re getting closer to perfecting it.

So how would you like to stay in bed for a several weeks? Do you think human hibernation is the key to interstellar travel?

What kind of technology would we need to stay asleep for weeks? Using today’s technology, a flight to Mars would take 8 months.

Traveling anywhere beyond that would take several years. But if you could sleep through it, the long journey might not seem so bad. And it would certainly be easier on resources.

So that’s what NASA, and other world space agencies are trying to figure out. Can humans hibernate? What will it take? And what are the risks?

When you think hibernation, bears or hedgehogs might come to mind. Winter, for them, is usually spent in a state of reduced metabolism. Their heart rate, breathing, energy consumption, and body temperature all decrease to conserve energy when food is scarce.

This is a state known as torpor. Plenty of animals do it, plenty of mammals do it, including some primates. So why not humans?

There have been a few rare examples of how humans have, sort of, replicated the hibernation process, but we haven’t quite been able to pull off the real thing.

And that’s because we’ve never really needed to. Communities in the coldest parts of the world generally found different ways to adapt; such as changing their diet, building igloos, or wearing animal skins. These, ‘climate hacks,’ might seem old-fashioned compared to today’s innovative approaches to human hibernation, but keep in mind that there’s still lots of work to be done.

The biggest concern is brain damage. Because we still don’t know enough about torpor, it’s hard to determine how it would affect the human brain.

When animals hibernate, they’ll come out of torpor for a few hours a day to get some much needed rest. Yeah, you heard that right.

While we might think that hibernation is just one big, long snooze, animal brain scans taken during torpor look the same as when they’re sleep deprived. It’s hard to know if this would be the same for humans.

Your brain might think it’s sleep deprived simply because metabolism, body temperature, and sleep regulation are all administered in the same part of the brain. So lower metabolism and temperature might be confused for less sleep. Or it could be a lot worse, since the brain might actually be damaged from lack of oxygen, nutrients, and sleep while in torpor.

With the brain functioning at minimum power, torpor reduces and reorganizes synaptic connections that are important to creating memories. So while you might wake up months or years after being put in hibernation, what will you remember of your life before hibernating? Will your best memories, your family, and your friends simply become dreams?

Without knowing how our memories would be affected over a long period of torpor, hibernating could result in some serious psychological trauma. But it’s not just your brain you have to worry about. How would you go to the bathroom?

Animals are lucky, since their waste is often reabsorbed to preserve nutrients while they’re hibernating, so they don’t really have to go until spring…

…As you know, humans can’t do that. So you’ll probably have to get comfortable with wearing a catheter.

So far, the closest thing we have to human hibernation is a medical procedure known as therapeutic hypothermia. This involves cooling someone’s body to 0º Celsius (32ºF), to slow their cellular and brain functions.

This practice has enabled people to recover from serious surgeries or strokes, but the longest it’s ever been tested is two weeks. A body temperature lower than 2.7ºC (37ºF) can cause painful complications in your digestive tract. It also compromises your immune system, making you more vulnerable to infections.

So brain damage, memory loss, indigestion, and disease. And don’t forget the catheter. There are enough compelling reasons to never want hibernate. Not to mention you’d have to miss out on several months, years even, of your life.

But is a part of you still tempted? Ever wonder what it would be like to set foot on Mars? Then start shopping for PJs, because we’re getting closer.

A company called Spaceworks is currently working on hibernation pods, and is hoping to soon make the shift from animal testing to human testing aboard the International Space Station. So it might not be too long before the red planet is only a sleep away.