What Are The Components of Sleep
we go to sleep, have a few dreams, and then wake up. But there’s a lot going on that you likely aren’t aware of. Sleep is made up of two major, distinct components -REM sleep and Non-REM (NREM) sleep.
Author:Paolo ReynaReviewer:James PierceJan 22, 2021160.2K Shares2.7M Views
What Happens When You Sleep?
For most of us, we go to sleep, have a few dreams, and then wake up. But there’s a lot going on that you likely aren’t aware of. Sleep is made up of two major, distinct components -REM sleep and Non-REM (NREM) sleep. REM is short for rapid eye movement (that’s what we do under our eyelids when we’re in this phase), and Non-REM describes all the other stages of your sleep. REM, besides the noticeable eye movement, is the time during sleep where we dream – most of our dreaming is here, although it can rarely be during some N3. It’s also where the major muscles of our body are frozen or paralyzed (researchers believe this is so we don’t harm ourselves or others by acting out our dreams). The are some specific brainwave patterns we see during the different parts of sleep, and REM is easily identified through these. NREM is divided up into three distinct phases (there used to be four, but in 2007 it was decided to group N3 and N4 together). Note that the Simply signifies a stage of Non-REM.
- N1 is the first stage, and it’s considered light sleep. This is the transition from being awake to falling asleep. People are very easily awoken from this stage. Actually, if you’re awoken here, you likely won’t believe you were asleep at all. If you’ve ever had sudden jerky movement of your leg, your foot or your arm while falling asleep, it’s because you were in N1. Very normal.
- N2 is much like N1, and it’s still considered light sleep. It’s also very easy to be awakened here, but it signifies some changes that are drawing us deeper into sleep. Our heart-rate slows, our body temperature begins to drop, and our brainwaves are exhibiting more sleep-related activity (“sleep spindles” and “K-complexes”). During N1 or N2, it’s very unlikely that you’re dreaming.
- N3 is the deepest part of our sleep – so that’s why it’s called deep sleep. This segment, like all the others, is easy to identify with our brainwaves – much slower than when we’re awake. It’s very difficult to wake someone in deep sleep, and if you succeed (sometimes an alarm clock will do this – but often you’ll sleep right through it), you’ll feel groggy and unfocused for quite some time. You’ve probably experienced this – it means you were awoken during some deep sleep.Because the body isn’t frozen during any of the N stages, N3 is is where you’ll find the parasomnia’s like sleep-walking, night-terrors and teeth grinding.
A Full Sleep Cycle
A “normal” sleep cycle for a “typical” adult will last for about 90 minutes – and we would go through 4-6 of these in a night:
It’s important to note that everyone’s “cycles” are different-different timing for a sleep cycle and different phases for each cycle. The time it takes for an entire cycle will tend to be static for one individual, but will vary from about 90-110 minutes from person to person. There are techniques to figure out what your cycle is. The route your sleep takes between phases (N1, N3, REM, etc) will be different for everyone, and likely different between cycles for each person (as you can see in the diagram – it’s different throughout the night). In the final analysis, a normal person will go through all the cycles – but in their own way on their own schedule.
Everyone is unique. And now you know what a night really looks like when you’re fast asleep…
Paolo Reyna
Author
James Pierce
Reviewer
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