Humans In Dark Isolation Develop 48-Hour Sleep Cycles, Sleep 30 Hours

By Sophia Maddox | May 24, 2024

Isolation Changes Our Perception Of Time

Isolation messes with our heads. Humans who lose contact with other people and the normal stimuli that occurs during the day react in strange ways. One of the weirdest things that our iso-brains do is change our sleep cycle until we're out for up to two days at a time. Admittedly, this is an extreme example, but multiple researchers have found that they don't just lose track of time, their sleep cycle in isolation changes from seven or eight hours a night to 48 hours at a time. In every case, these researchers have no idea how long they're actually sleeping because it just feels normal.

Even if you aren't sleeping in a cave beneath the Alps, your body and mind can warp in isolation. Staying inside for days on end can make you lose track of time and sleep as if you're in a kind of soft hibernation. Researchers are still trying to understand why.

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(Alexander Kumar)

It's not a stretch to imagine that without any way to tell time, our grasp of the hours and days slip away. Researchers who've spent long periods in isolation have found that "time-shifting" is a normal part of isolation. In 1961, French geologist Michel Siffre abandoned his watch during a two-week expedition of a glacier beneath the French Alps in an attempt to discover how humans deal with darkness and extreme solitude, and before he knew it, two months had gone by. Siffre maintained contact with his team above ground, who discovered that his perception of time had stretched over the course of his stay beneath the Alps to the point that it took him five minutes to count to 120 seconds. It's no wonder he didn't realize that entire months of his life slipped away.

The 48-Hour Sleep Cycle In Isolation

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What researchers have found after studying the isolation of Maurizio Montalbini, as well as scientists Josie Laures and Antoine Senni, is that our isolated bodies adjust to a new schedule (if that's what you want to call it) in which we sleep for up to 48 hours in one cycle. In 1993, Montalbini spent 366 days in an Italian cave that was designed by NASA to simulate space missions, but when he returned to life above ground, he believed that he'd only spent 219 days in the cave. This lapse in his perception of time was caused by his sleep-wake cycles nearly doubling in isolation, without any clear reason why. 

As horrible as all of this sounds, Montalbini's research into isolation has helped scientists get a somewhat tenuous grip on what happens to our internal chronometer when we're left to our own devices for long periods of time. That being said, we're still a long way from understanding why our bodies lengthen our sleep cycles.