Author: Mike and Matty
I used to think that sleeping was a complete waste of time. Your eyes are closed and your body is motionless. You are literally doing nothing. How could sleeping be productive?
But the more all-nighters I pulled (to study or keep productive) the more I started to notice the effects of poor sleep. This motivated me to learn more about how the brain works while we sleep.
I’m sure you already know that getting enough sleep helps you recover energy for the next day, so I’m not going to bore you with that discussion. But if you look at the science of sleep, you’ll realize that not only is sleep productive, it might be the most productive thing you do all day (and all night).
During a full night of sleep, our brains transition between three different types of sleep: Deep sleep, light sleep, and REM sleep. We cycle through all three of these phases about every 90 minutes, and each subsequent cycle is a little different from the previous. The first sleep cycles right when you fall asleep contain more deep sleep, and the last sleep cycles right before you wake up contain more light sleep. It’s important to understand what happens in each of these phases in our brain to see the full picture.
You can think of deep sleep as taking and storing notes. Throughout the day, when you learn new information, such as from class or at work, your brain stores that information temporarily as notes in an area called the hippocampus. During deep sleep, your brain attempts to file away each of your new notes into a more permanent place in your brain, in an attempt to save your work.
If you decided to stay up late and miss out on the first sleep cycles that are heavy in deep sleep, you risk not saving your work. The hard-earned notes that you gathered that day could be lost forever. Because right after deep sleep comes light sleep, which is analogous to the cleaning phase. During light sleep, your brain gets rid of all the leftover notes that you didn’t care to save from your hippocampus. Without this cleaning phase, your hippocampus will remain full, which makes it difficult for you to learn and add new information.
Just as how going to sleep late sacrifices your deep sleep, waking up too early sacrifices your light sleep (see the chart above). When you wake up too early and get only 4–5 total hours of sleep, you aren’t efficiently preparing your brain to learn new information.
And finally, REM sleep is when your brain makes new connections between all the old and new notes you’ve stored in your memory. The later sleep cycles contain the majority of your REM sleep, which could explain why some people might discover creative new ideas in their vivid dreams soon before waking.
In summary, deep sleep helps us save information, light sleep helps us learn new information, and REM sleep helps us make sense of our information. To put it into RemNote terms, deep sleep is when we put tags and references on our notes, light sleep is when we prepare a new daily doc for tomorrow’s notes, and REM sleep is when we better understand our notes through bi-directional linking and spaced repetition.
