Your Sleep Cycle
I woke this morning at the wrong point in my sleep cycle.
The first thing I knew was an annoying cock crow that confused the fuck out of me. Not a real rooster mind you – I use a random selection of bird noises to get me up each morning. I’m not even sure why… maybe the different sounds stop me getting used to the alarm? And, generally, I do like to wake to more natural sounds than the ‘Reveille’ (that bugle call used by the military to wake everyone at sunrise), or a version of ‘the Auld Triangle’ going jingle jangle, like they used in Mountjoy prison to wake the inmates.
Alright so I know there’s other options for alarm noises to disturb your sleep cycle, but I was going for the most annoying but effective ones I could think of. Your methods may vary.
What is the Sleep Cycle though?
A sleep cycle lasts about 90 minutes, and during that time we move through five different stages of sleep – some of which you might already be familiar with, at least in passing. The first four stages make up our non-rapid eye movement (NREM) sleep, from very light sleep during Stage 1 to very deep sleep in Stage 4, where it’s really tough to wake someone from. When we’re in NREM sleep, we don’t have much (or any) muscle activity, and our eyes don’t usually move. But all of our muscles are still functional, which changes when we move to the fifth stage, when rapid eye movement (REM) sleep occurs.
REM sleep is when most of our dreaming is going on, and though our eyes are not constantly moving, they do dart back and forth, up and down. Nobody really knows even yet why our eyes move, but one of the generally accepted theories is that it’s related to visual images we’re watching play out in dreams. During this stage of the sleep cycle, our eyes are going like nobody’s business… but the muscles that move our bodies are paralyzed (except things like the heart and diaphragm, coz obviously we’re still alive and breathing).
This paralysis sounds a bit grim, but it’s actually stopping us from getting up and moving around while our subconscious and unconscious are doing their thing, which is useful for those of us who don’t want to walk out into traffic in our nighties, or attack the person sleeping next to us because we think they’re doing something nasty due to a dream that’s going on. A breakdown of this natural paralysis is why people go sleepwalking or get night terrors in which they do some pretty awful things while effectively unconscious.
Honestly, you don’t want that.
A typical night’s Sleep Cycle
Unfortunately, it’s not as simple as just running together a couple of 90 minute sessions and calling it a night. To understand your sleep cycle, we have to get that they change throughout the night.
During the first two to three sleep cycles, you’ll spend most of your time in deep NREM sleep (stages 3-4), but in the final two to three sleep cycles, you’ll be more in REM sleep with some lighter NREM sleep. It’ll also change according to when you fall asleep, as the earlier parts of the night tend to bring more NREM sleep, and also what stage of life you’re at, as kids tend to get more deep NREM sleep than adults.
How to Optimise your Sleep Cycle
Getting woken in the middle of REM sleep, like I was today, is not ideal.
It leads to that sensation of grogginess, a poor reaction time, and general fog that’s actually called sleep drunkenness, or confusional arousal. Being woken from REM can cause significant mood problems, and your blood pressure goes up. Like, it’s not optimal at all at all.
There’s tech you can use to track your sleep cycle and wake you naturally based on finishing one and before you start another. That’s amazing, but I don’t have that tech. (If you use something like that and find it useful, would you mind popping over to Our Facebook Group and giving a recommendation?)
Generally, I stuck with analog, and just tracked my sleep and how I feel the next day in my bullet journal, over about two months (not perfectly, as we’ve seen I’m not good at filling in trackers) to try to figure out what’s best for me.
I came up with a minimum of 7.5 hours and a max of 9 hours, if I can get it. That’s 5 or 6 sleep cycles, respectively. So I figured out that if I need to be awake by 8am, I’m going to sleep by 11pm to get my 9 hours, and that means tech off by 10pm and reading, journalling or talking (or Jon reading something not too interesting to me!) til I fall asleep, which usually takes around the hour to wind down.
Have you figured out your own sleep cycle yet?