The 5 Stages of Sleep

Sleep is a strange thing.

We spend a third of our lives doing it, but it’s actually one of the most poorly understood aspects of modern psychology.

It wasn’t until the 1950s, in fact, that researchers started to uncover the true complexity of the sleeping mind.

It’s not as simple as just drifting off to dream-land and waking up in a couple hours – in the time between clocking out at night and waking up in the morning, your unconscious brain has actually passed through a whole rollercoaster of various states and stages.

As we progress through the night, our mind takes us into a baffling, bizarre journey that remains every bit as mysterious as human nature itself.

Stage 1: Light Sleep

Your sleep is divided into a total of five stages, all of which your brain passes through at some point throughout the night.

The first of these, uninterestingly titled “Stage 1,” typically lasts for around seven minutes right after you’ve drifted off.

Image: A woman asleep in bed

Many people experience random, vivid hypnogogic hallucinations during this period, where you might sometimes feel as if you’re falling or imagine you hear someone calling your name.

Although it might not always feel like it as its happening, there actually is a precise moment at which you fall asleep.

Your brain starts emitting things called “alpha” and “theta” waves during Stage 1 sleep, and researchers can actually pick up on this stuff with device known as an electroencephalogram. 

Basically, the electrical currents that continually run through your brain start to take on a different pattern, reflecting your current state of mind.

By sticking a couple electrodes to your skull and checking out your brain waves as you drift off, researchers can actually track the journey of your mind as you travel deeper and deeper into your subconscious.

Because stage one is a very light period of sleep, a lot of people sometimes don’t even realize that they’ve drifted off.

This is especially common in people with insomnia, where your brain is generally in a state of hyperarousal.

Your waking thoughts can intermingle with your dreams during this period, so if you’re having a rough time sleeping and check the clock frequently, you might think you’ve been awake for hours and hours when really you’ve just been drifting out of Stage 1 sleep!

If you’re severely sleep deprived, researchers have also found that some people can drift off into “microsleeps” throughout the day without even realizing it.

 These periods of unnoticed unconsciousness can last anywhere from a fraction of a second to up to 30 seconds, and as you can imagine, they’re often quite dangerous.

Stage 2: The Body Slows Down

In Stage 2 of your sleep cycle, your body drops into a slightly deeper sleep, although you can still be fairly easily awakened.

Your heartrate slows down, your body temperature drops, your breathing deepens, and your body as a whole gets ready for deep sleep. 

Even as your processes get slower, though, your brain also begins to produce this short, high-frequency jolts of electricity known as sleep spindles (not to be confused with the Spindle mattress!).

Science still isn’t entirely sure what these spindles are supposed to do, but they might help your brain sort through your memories from the day and strengthen specific synaptic connections.

Sleep spindles become more common in Stage 2 after intensive learning experiences, and they may also help keep your brain from being woken up by outside stimuli while you’re asleep.

Stage 2 of the sleep cycle usually lasts around 20 minutes.

A well-timed nap will usually end somewhere in the middle of Stage 2 sleep, since the effects of sleep inertia aren’t usually that severe – that is, you’ll be able to snap back to the waking world pretty quickly, instead of getting bogged down in that grogginess you’ve almost certainly experienced. 

Stage 3: The Brain Transitions

In Stage 3, we really start to see the brain prepare itself for the very deepest sleep.

Slow delta waves began to emanate from your brain, and as your brain sinks ever further away from the waking world, it becomes increasingly difficult to rouse you.

If you’re woken up during Stage 3 sleep or later, you’re probably going to feel pretty sleepy.

Your brain is now getting ready for a full night of sleep.

Stage 4: Deep Sleep

At Stage 4, we finally get to the last stage of non-REM (NREM) sleep.

Image: A forest in the dead of night

Delta waves are very common now, and in fact, sleep stages 3 and 4 are sometimes referred to as Slow Wave Sleep, or SWS.

Sleep-deprived patients have been found to have much longer periods of SWS, suggesting that it’s critical for proper function.

Deep sleep is where your body repairs itself—healing damaged tissues, strengthening your muscles and your bones, beefing up your immune system, etc.

Stage Five: Dreams and REM

The fifth and final stage of sleep is commonly referred to as rapid eye movement, or REM.

This period kicks in between 80 and 100 minutes after falling asleep, and it’s where a lot of the freaky sleep stuff starts to happen.

Your body paralyzes all voluntary muscles with the sole exception of the eyes, which dart around erratically (about seven times every minute).

This near-complete paralysis is actually highly useful, since your brain has now passed into that realm of bizarre hallucinations we like to call dreams.

REM sleep has been found to substantially improve many different kinds of learning, especially new skills and problem-solving techniques.

Unlike other sleep cycles, which have been observed in many different, REM sleep is unique to mammals and birds.

This is interesting, since mammals and birds are both substantially more intelligent than any other vertebrates, but their most recent common ancestor was a reptile.

Since reptiles don’t undergo REM sleep, this sleep stage apparently evolved independently in both mammals and birds!

How Your Body Cycles Through Sleep Stages

Now, although the five stages of sleep take place cyclically throughout the night, it’s important to realize that the cycles your body goes through aren’t as simple as you might expect.

Healthy individuals shuffle through these stages several times throughout the night (usually around five times).

Image: A child travels through the landscape of a dream

However, we don’t go through the five stages one by one.

 We start out at Stage 1, and then progress through Stages 2, 3, and 4.

After we hit Stage 4, though, we don’t just immediately shift into REM sleep before starting the cycle again.

Instead, we switch back to Stage 2, and then go through Stages 3 and 4 again before finally going back to REM.

After REM is over we’ll usually pop back up at Stage 2, although we may also wake up briefly in the night at this point.

The amount of time we spend in REM and deep sleep becomes longer and longer throughout the night.

Near morning, in fact, the REM stage may last as long as a whole hour!

This is part of why it’s so important to get the amount of sleep you need.

When you’re sleep deprived, your body will often progress more quickly into deep sleep and REM, and it’ll also spend more time there.

That said, though, there’s no way to completely make up for lost sleep other than simply sleeping more.

Your body takes a lot of maintenance to keep running smoothly 16 hours a day, and it really does need those extra eight to keep in top-notch shape.

How to Get Better Sleep

There are a lot of different tricks you can try to increase the amount of time you’re spending in the most crucial stages of sleep.

The most obvious one is to simply budget more time into your schedule for sleep.

It really is important, and you can’t just expect your body to keep running on empty forever!

That said, there are a lot of reasons why merely finding a couple extra hours in your week may not be a viable solution for you.

A lot of us are running some pretty tight schedules, and we’re frankly lucky if we can work in anything close to the amount of sleep time we need.

For others, just getting to sleep and staying asleep may pose a serious challenge in and over itself.

After all, the amount of time you spend sleeping isn’t the only thing that matters.

Quality of sleep is just as important!

Because of this, it’s critical that you spend some time working out the most comfortable sleeping environment you possibly can.

You need the right blankets, the right pillow, and, of course, the right mattress. 

This last item is arguably the most important part to get right, since it’s pretty much impossible to get reasonably comfortable on a poor-quality mattress.

Good mattresses aren’t just reserved for the uber-rich, after all—there are plenty of affordable, highly comfortable out there just waiting for smart shoppers to buy.

If you think that’s something you might find helpful, here’s a quick link to the top products out there today.

I’d especially recommend the Saatva and Amerisleep3, but it’s all about personal preference.

The point is, take some time to get this part of your life right.

Your sleep is a complicated thing, and you certainly don’t need something as silly as a bad sleep environment standing between you and a better-rested, happier, and more productive life.

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