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The Science of Sleep

Sleep is a natural process that leaves us feeling refreshed.

Lack of the same links to mental & physical health problems like stroke, heart disease, etc.

Let’s see the science behind sleeping, and how to effectively sleep

The Science of Sleep

The core of how we sleep can be understood by understanding the Circadian rhythm, sleep cycles, and chronotypes.

What leads makes us sleep? Adenosine. It’s a chemical compound that regulates brain activity and mood, when it binds with an ‘A1’ receptor, it promotes relaxation and sleep. As the day goes by, more Adenosine binds with these receptors. This is then broken down when we sleep.

Does coffee make you feel refreshed? It binds with A1 receptors so Adenosine doesn’t.

The Circadian Rythm

You’ve probably heard of this before. It’s commonly called our internal clock.

It plays a part in sleep-wake cycles. When exposed to light, it promotes alertness. When exposed to darkness, it creates Melatonin, a hormone that promotes sleep.

This is the reason we usually feel sleepy around 1–3 P.M

Sleep Cycle

The first stage of the sleep cycle relaxes our muscles, heart rate, and breathing. It usually lasts a few minutes.

Stage two is the longest of the four. During this stage, our brain wave activity remains slow, heart rate and breathing continue to slow down as our body temperatures also drop and muscles relax further.

Stage three plays a big role in feeling ‘refreshed’, during this stage muscles are the most relaxed. Breathing, heart rate, and brain wave activity are the slowest. This stage decreases in duration as the night goes on.

The fourth stage is REM sleep, which is rapid eye movement. As the name suggests, our eyes move rapidly beneath our eyelids, and our brain starts to become more active, we start having dreams + our hands and legs become paralyzed! This is believed to stop us from acting out our dreams.

This entire cycle lasts about 90 mins. It’s likely that if we wake up in the middle of REM/deep sleep we’ll feel groggy.


This is something else that regulates when we sleep. But chronotypes are not necessarily trainable. They’re cooked into our genetics.

There are 4 types.

How To Sleep

Now that we know the science behind sleep, how does one improve sleep quality/quality?

The first thing we can do is something you’ve probably heard before, no caffeine 10 hours before bed. This is because that’s how long it takes caffeine to get out of our bodies. We may be able to sleep with a little caffeine in us, but that affects quality. This also includes things like dark chocolate.

Keeping the room temp around 19c. Warmer room temperatures result in fatigue and lead to feeling stuffy — making it hard to fall asleep.

Training out circadian rhythms — keeping a routine of sleeping and waking up at the same time every day (doesn’t matter if it’s a weekday or weekend) regulates the circadian rhythm. Not doing so can result in feeling tired at the wrong times and little and low-quality sleep.

Screens emit blue light. This messes with the circadian rhythm, making our bodies think it’s daytime and producing less melatonin. Hence, it’s best to avoid screens and bright lights before sleeping. It could be advisable to have a bedtime/wind-down routine.

On similar lines, when waking up it’s best to get some natural light to make our bodies realize it’s daytime and it’s time to feel energized/alert.

Another thing to keep in check is reserving our beds solely for sleeping. If we are used to scrolling through Twitter in bed, the next time we go to bed, our brains will seek a dopamine release instead of wanting to sleep.

Lastly, high-intensity workouts 60–90 minutes before bed can disrupt sleep. However moderate-intensity workouts such as Yoga or walking seem to have no effect.

How to Nap

Yes, there is a way. Napping can be a great way to restore energy from that afternoon dip seen in the circadian rhythm graph above.

However, doing it the wrong way may result in feeling more tired than we were before taking a nap.

The ideal nap is anywhere from 15–20 mins, before 3–4 pm, and in similar conditions as proper sleep (dark, and temperature around 19c)

Learning and Sleep

The correlation is simple. Our brains tend to absorb information better after a good sleep and tend to remember what we learned better because our memory consolidates as we sleep.

Hence, a lack of sleep because of pulling an allnighter actually reduces the quality of learning.

In all honesty, I don’t really do most of this either, however, I’m trying to get better at it. I’ve just been finding the science of sleep interesting and wanted to share everything I’ve learned.

If you’ve found this interesting, I highly suggest giving Mathew Walker’s Why We Sleep a read, this blog was mainly inspired by it.

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