Sleep Awareness Week: The Different Stages of Sleep and Their Importance

March 8-14 is Sleep Awareness Week, and to celebrate, we are reviewing the different stages of sleep, their importance, and what that means for overall health.

Good morning! Or, depending on when you read this article, good afternoon, evening, or night. No matter what time of day it is for you, you have almost certainly engaged in something every human does very often – sleeping – in the last little while.

But how good did you sleep? Did you wake up feeling refreshed and ready to take on the world, or did you find yourself sore, struggling, and annoyed at yet another night of chronic insomnia? In honor of Sleep Awareness Week, we want to help you understand what’s happening at night and how you can improve the quality of your sleep, too.

What Exactly Happens When You Sleep?

In an otherwise healthy person who tends to sleep well, the process of falling asleep and staying asleep is actually quite similar. You lie down, close your eyes, and slowly drift off into a semi-conscious state. From there, you eventually drift into an even deeper state of unconsciousness – this is when your body goes into self-repair mode.

These different sleep states are referred to as stages of sleep, and we’ll talk a bit more about them shortly. But for now, what we want you to know is exactly what’s happening in your body chemically and neurologically when you sleep.

First, your brain releases chemicals that induce each of the five unique sleep stages; these “states” cycle over a 90 to 110-minute period. Brainwaves change, becoming slower or faster, and your body relaxes. Eventually, the brain begins to ignore external stimuli, such as small noises and movement. The deeper sleep becomes, the less likely you are to awaken to these minor sensory inputs.

In the deepest levels of sleep, your brain actually releases chemicals that have a mild paralytic effect on your muscles. This might sound scary, but it’s really just to protect you from falls and other accidents while you’re snoozing. This may also be why some people struggle with sleep paralysis!

Next, let’s talk more about the actual stages of sleep and how they differ.

The 5 Stages of Sleep

In theory, most forms of sleep actually fall within two distinct categories: Rapid-Eye Movement (REM) and Non-Rapid-Eye Movement (NREM). However, this doesn’t really tell us everything we need to know about how we progress through the stages or the kind of impact each stage has on your health. Each individual sleep stage is important or carries some kind of unique benefit. A good sleep contains all of them.

Stage 1 – Wakefulness

This one’s pretty straightforward – it occurs when you are still awake and includes the moments when you are preparing to sleep by relaxing your body or maybe closing your eyes. It isn’t a true “sleep stage” per se, but most resources do include it because you can’t really have true sleep without it!

Stage 2 – Light NREM

This stage occurs when you have been lying down trying to sleep for a time. You may be aware that you aren’t quite asleep yet, but find your mind daydreaming or even experiencing small little “quick dreams” that seem to evaporate as you float in and out of consciousness. Someone who is napping on the couch for 10 minutes or less is likely to experience this stage only – and they may even deny being asleep!

Stage 3 – True NREM

If you spend enough time in Stage 1 sleep, you will eventually transfer into a state of defined NREM sleep. Your brain sends out signals to your body to reduce temperature, relax the muscles, and slow your heart rate. Brain waves also change in nature, switching into a pattern that’s less likely to allow you to awaken easily. However, you can still be woken with only minimal sensory input.

Stage 4 – Deep NREM

Deep NREM is considered the deepest and most important form of sleep. This is because it is when your body goes into self-repair and restoration mode. Brain waves shift into delta waves, slowing dramatically, and you become much harder to awaken even with prompting.

Research also shows that failing to get enough deep sleep can also be directly harmful; in fact, it may even greatly raise your risk for certain illnesses. Science isn’t sure yet whether this is a result of impared self-healing or some other mechanism. Still, we know enough about it to know that it’s extremely important.

Stage 5 – REM

Rapid-eye movement sleep is when your brain is actively “dreaming.” Brain waves become much, much more active, and dreams are experienced – but you may not always remember them after you wake up. You also remain very difficult to awaken, but less so than if you were in deep sleep. If you are woken up, you will very likely feel groggy as the brain struggles to transition into full wakefulness from REM.

Why the Stages of Sleep Matter So Much

There is still so much to learn about why a good sleep is so beneficial, but that doesn’t mean we don’t know anything already. Science has proven, time and time again, that all five stages of sleep directly influence health, rejuvenation, healing, and even how well the systems within your body function.

Not getting enough of even one of these stages can leave you feeling exhausted and suffering an increased risk for certain medical conditions, like heart disease and diabetes.

How to Improve Sleep Cycles

If you have been struggling to sleep or find yourself waking up exhausted, your sleep cycles may be struggling. There are a few ways to improve things.

• Skip the caffeine before bed. In fact, stop drinking anything caffeinated by two in the afternoon if you plan to go to bed around 9:00 p.m. or 10:00 p.m. This may seem excessive, but some people do process caffeine more slowly, which could leave you feeling too awake to sleep.
• Turn the lights down at least an hour before bed. This includes smartphones, televisions and tablets, which all emit wakeful blue light. You might try using the “night filter” option, if your device has one (this eliminates blue light, making the screen appear slightly orange). Or, you might just knock the brightness setting down a few notches.
• Don’t have a nightcap. While alcohol may help you fall asleep, it interferes with the stages of sleep, which can leave you waking up suddenly within an hour or two. You may also find you can’t fall asleep again once you awaken.
• Get on a schedule. As much of a pain as it might seem – especially if you’re on vacation or retired – sticking to a sleep schedule is the best thing you can do for your sleep. Get up and go to bed within an hour or two of the same schedule every single day. Over time, this will improve your cycles.

Time for Sweet Dreams

And we’ve saved the best tip for last – ask for help. Lack of sleep or feeling as if you don’t sleep well may be a sign of sleep apnea, mental health struggles, and other common illnesses. Don’t feel that you need to struggle with this alone. There are excellent options available to help get you back on track.