Since we spend a third of our lives doing it, you'd think we know by know exactly why we sleep. Sadly, all we have is best guesses.
Sleep has always fascinated me.
As a kid I got to have lucid dreams where I could fly around my town like superman, controlling where and how fast I few. It was exhilerating and the sense of complete freedom was fantastic.
By comparison, it made the real world seem rather dull.
Dreams -good dreams - are an amazing place where rules don't exist and you can make anything happen. It feels like a personal Matrix, where you get to control everything.
It also intrigues me that the sleep world and the dream world felt equally real, but disconnected, like they aren't allowed to touch. When I wake, the incredibly rich & vivid dream world often fades quickly from view... in just a few seconds, I can barely remember what I was dreaming about.
Where did it go? How can something so incredibly real suddenly disappear as though it were yanked from my short-term memory. Why does my mind do that? These expereinces raised some very interesting questions about the nature of consciousness, and the differences between waking consciousness, and sleeping consciousness.
My most unique sleep experience ever...
Perhaps the most interesting sleep experience I've ever had was a very brief one, lasting about 5 seconds, which I still remember vividly to this day.
At around 11 years old, my alarm clock woke me one morning before school and I was extremely tired. More tired than I think I've ever felt before - just unbelievably tired.
I felt like I'd been run over by a truck.
In that moment, I knew I absolutely had to get up right now for an important school test, but I was also completely dysfunctional, and had to sleep.
In a split second decision, I compromised....
I was going back to sleep ... for one more minute.
I set my alarm clock one minute ahead, and closed my eyes.
In my head, I knew I needed to get an entire night's sleep in 60 seconds flat. I had zero time to waste, and I needed to fall asleep fast. The feeling of forcing myself to fall asleep that quickly was a bit terrifying. There was a moment where I felt like I was diving into a mysterious black hole, between waking and sleeping, and it wasn't certain I would be able to find my way back.
The thought actually flashed through my head that I might die.
But I had no choice. 60 seconds. Tick, tick...
I dove in head-first.
Instantly I fell asleep completely, and just as instantly, I was wide awake again, feeling great.
I felt completely rested - like I'd just had the best sleep of my life... it was uncanny. I felt like I had just slept for an entire week.
It felt like hitting the reset button on the front of your computer. Boom, it's offline, and just second later it's back up, completely fresh, with none of the clutter that filled your screen moments before.
Ever since then, I've been left with the strong suspicion that sleep and rest, are not the same thing.
Why do we sleep?
You think we'd understand why we sleep, but we don't. There are a lot of theories that involve crucial physical, chemical, neurological, and psychological processes.
Some of these...
- DNA repair
- Physical repair ( requiring physical immobilisation )
- Hormonal balancing
- Waste management. Cleaning out the inter-cellular waste in your brain, using cerebro-spinal fluid and the lymphatic system.
- Long term memory and neural pathway formation,
I hope that scientists will understand more of the reasons, because it appears that at least some of these processes can occur during meditation.
Is it possible to never sleep?
Stories like Al Herpin's - the "Man Who Never Slept" - are quite popular, because if we could learn to turn off sleep, who wouldn't want 30% more time in their day?
There are actually quite a few legitimate-sounding stories of people who never sleep, however, to my knowledge, none of them have been subjected to rigorous scientific study. In cases that have been explored scientifically it's been observed that the subject does sleep in very short bursts, that they're not even aware of - which sounds very similar to my own 5-second sleep experience.
If someone suffered from a condition where they could not sustain sleep, perhaps their brain would adapt to short bursts of sleep to sort out its essential processes.
Learning from our animal cousins
One question that keeps occurring to me is...
Is 8 hours of sleep needed because we have big, powerful brains?
I turned towards a bit of evolutionary study to learn more. Logically, if sleep exists primarily for our brains, then animals with smaller brains might require less sleep, and animals with no identifiable brain may not require sleep at all.
In the words of this fascinating Wikipedia article...
If sleep were not essential, one would expect to find:
- Animal species that do not sleep at all
- Animals that do not need recovery sleep after staying awake longer than usual
- Animals that suffer no serious consequences as a result of lack of sleep
[However, ] outside of a few basal animals that have no brain or a very simple one, no animals have been found to date that satisfy any of these criteria.
In fact, most animals appear to need some sleep, which suggests that somewhere in the evolutionary process, the development of certain animal characteristics - perhaps our neurological systems - required a period of shutdown.
In fact, most lifeforms on Earth follow a cycle known as the circadian rhythm, which is a 24 hour "solar based" internal clock that affects our chemical, psychological and behavioural processes. It seems likely that this is at least one of the causes of the experience of jet lag.
But, not all animals sleep the same way we do
Even with overwhelming evidence that sleep is essential for pretty much all animals, there are some very interesting "special cases" in the animal kingdom, which raise interesting questions about sleep and how we approach it...
- Migrating birds must fly for extended periods, and aquatic mammals such as dolphins must surface to survive. Some of these species have developed a unihemispheric (USWS) sleeping pattern, in which only half of the brain sleeps at a time. This allows them to avoid death by plummeting from the sky, or drowning, while still achieving the necessary sleep. ( It does raise a lot of interesting questions about whether e.g. dolphins have different personalities, or lose language skills, during those hemispheric shifts.
- Some sharks species, must keep moving in order to oxygenate their gills. While their sleep habits ( as well as fish overall ) are not well studied, they perhaps represent the most interesting case of a larger non-sleeping animal, as they do not appear to engage in the USWS sleeping of dolphins.
- Mammals' feeding habits are associated with their sleep length. The daily need for sleep is highest in carnivores, lower in omnivores and lowest in herbivores. Many large mammals, such as horses, elephants, cows, and giraffes ( all herbivores ) only require half as much sleep as humans. As measured in captivity ( which may be different from in the wild ), horses require the least at only 2 hours of sleep / day.
- Animals which hibernate still need sleep, separately, and will stop hibernating in order to sleep.
Do we really need 8 hours of sleep?
Most people today believe that sleep is done best in a single 8 hour chunk. But where did we get that idea?
Prior to the industrial age, people slept in two chunks of about 4 hours each with a few hours of wakefulness and activity in-between.
This is known as bi-modal sleep and was apparently the preferred way to sleep, for millennia.
One hypothesis here is that prior to the invention of electricity and electric lighting, it was difficult to do much that was useful at night. As winter nights in some parts of the World often last longer than 8 hours, perhaps people simply adapted to that reality as best they could.
Another interesting approach is known as polyphasic sleep, in which humans can reportedly train their minds to enter REM-sleep more quickly, and sleep on a cycle of 20 minutes every 4 hours. Altogether this is a grand total of 2 hours sleep per day, which some report is sustainable and may even be the most natural sleeping pattern for humans.
Exploring your own sleep
If you're interested in this, it's worth exploring your sleep just as you would any other area of self-development. Learn about it, explore it first-hand, experiment wildly and journal everything. You'll be better for it.
Key questions you can explore...
- Am I better suited to bi-phasic sleep, with an awake chunk in the middle of the night where I read, study, clean, etc.?
- Does poly-phasic sleep work? Can I actually reduce the total number of hours of sleep I need by taking the cat-nat approach.
- Does what I eat affect how much sleep I need, and how well I sleep? What does cutting out meat & dairy do to my sleep?
- Can I use sleep more effectively, to benefit ot areas of my life such as learning, problem-solving, or creativity?
Can I use sleep more effectively?
With question #4, things get interesting.
There's a lot we don't know about sleep, but one thing we can be certain of is that while we're sleeping, we're in a different conscious state.
Recently I have been exploring the edge of sleep - the space between when you are in sleep-consciousness state, and in our normal "fully conscious" state. For me the best time to do this is while I'm waking... I notice the world, and become aware of my consciousness, but I am not awake yet.
That boundary is interesting, because at least for me, my mental state is much different. It's more fluid and less constrained by a sense of "reality" and physical constraints.
In particular I notice-
- Problem solving feels supercharged, because there are no rules to obey. This creates a sense of unlimited possibility. It doesn't matter what kind of problem it is either, I've tried technical problems, relationship problems, philosophical problems...
- Thought is not so much linear, as it is simultaneous - a million different approaches can be considered at the same time. In my perception, this feels a bit like the difference between modern threaded computer processor architectures ( one thing at a time ), and quantum computing ( everything at once ).
- Emotion doesn't interfere. Even personal relationship conflicts that I'm facing in my real world can be explored with zero negative emotion, and seem so much clearer and easier to solve.
I've read of people using this by setting themselves a problem to solve ( as they go to sleep ) and then discovering they answer to that problem on awaking.
Some believe that sleep is a fundamental part of our learning process. It's thought that sleep might be the place where-
- Your mind reviews all of the information you collected that day
- It determines what's important to keep, and moves it to long term memory. Often this is done with the help of emotion. This is why things that you experienced with emotion are more easily remembered, whether or not you want to.
- It discards everything else, clearing out your short term memory stores.
I've experimented with this to great effect. Try learning a dance move, martial arts kata, guitar song, some Russian vocabulary, etc. just before you take a nap.
On waking, my experience is that that new information feels solidly "learned" and easy to recollect.
Some key points to take away...
- If it's going to cost you about a third of your life, you should probably learn what you can about sleep, and how to get the most out of it.
- Chances are, you could be sleeping better and more naturally than you currently are.
- Maybe, possibly, you might be able to sleep less than 8 hours, with all the rest benefits.
- Sleep state may offer some advanced mental states that we don't know how to use well yet, which can be applied to things like learning and problem solving.
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Personal note on jet lag- I used to fly regularly between Chicago and Moscow, and discovered that in one direction I would experience noticable jetlag, but in the other direction, none at all.
Hypnosis and its relationship to REM sleep state
A TED Talk discussion by hypnotist Albert Nerenberg;
Professor Michel Jouvet - "The Christopher Colombus of Dreams"
Experimental Medicine at the University of Lyon