Why we sleep

 

"Scientists have discovered a revolutionary new treatment that makes you live longer. It enhances your memory and makes you more creative. It makes you look more attractive. It keeps you slim and lowers food cravings. It protects you from cancer and dementia. It wards off colds and the flu. It lowers your risk of heart attacks and stroke, not to mention diabetes. You’ll even feel happier, less depressed, and less anxious. Are you interested?"

The ad isn't about a miracle cure-all drug, but rather the scientifically proven benefits of a full night of sleep.

How much should you sleep(optimal amount)?

According to Matthew, it's 8 hours of sleep opportunity at night and 30-60 minutes nap in the day (before 3 PM). During the afternoon, it's natural to feel sleepy. If you have to give a presentation or any performance, better not schedule it in the afternoon.

You might think that you're able to function properly by sleeping 6 hours. If you regularly sleep 8 hours and choose to sleep 6 hours for a day, you distinctly feel sleep-deprived. But if you regularly sleep 6 hours, you don't feel sleep-deprived. The thing is you don't feel sleep deprived when you're always sleep-deprived.

Modern society and sleep

Sleep is so fundamental to life that every single organism on the earth has a state physiologically similar to it. Sadly, modern society fueled by capitalism views sleep almost as a waste of time. People get praised for sleeping 5 hours to grind more while sleeping for 8 hours is termed as being "lazy". Even if you have a lot of work, not sleeping for 8 hours doesn't make sense. Your learning capacity, concentration, energy levels, mood stability, and creativity are all dampened by the lack of sleep. As a result, you become highly inefficient and the quality and quantity of your work are reduced.

Alzheimer's is caused by the accumulation of amyloid protein in the brain. One function of sleep is to clean the brain by removing such proteins from the brain. Therefore, Alzheimer's is closely related to sleep (so is Dementia). Currently, Alzheimer's and Dementia among the elderly are rising rapidly (especially in the first world). This also happens to be the generation where sleep neglect became mainstream. Matthew argues that the accumulation of sleep neglect in adulthood significantly increases your risk of developing Alzheimer's and Dementia when you grow old.

Two phases of sleep (NREM and REM, latter linked with dreaming)

We have two memory storage sites: temporary and permanent. NREM sleep transfers your memories from the temporary site to the permanent site, freeing up space in the temporary site for the next day. So from a learning perspective, sleep is undeniably important. The memories you form when sleep-deprived evaporates quickly. You might retain it for a day, but it's gone after that.

When our ancestors moved from sleeping on top of trees to the ground, we started having a lot of REM sleep. One function of it is that it helps us understand emotional nuance. Humans can predict when someone is sad/happy by simply looking at their facial expressions and body gestures. The gift of REM sleep made us capable to form civilizations larger than any other animal. Humans are vastly superior to other animals because we dream more and better.

During the REM phase, your body is paralyzed so that you don't act out your dream movements.
Sometimes, your brain forgets to undo this even after you're awake. REM sleep still lingers in your body and you hallucinate when this happens. This is called "sleep paralysis". It happened to me when I was in grade 7. I thought I had seen a ghost at that time. If you've encountered a similar experience, don't worry since this is quite common.

Inside the mother's womb, most of the brain development of the child happens during REM sleep. The paralyzing ability isn't fully developed in them. The kicks that the mother feels are actually the baby moving during its REM sleep.

Driving while sleep deprived 

More accidents are caused by drowsy driving than alcohol or drugs. If you have ever stayed awake continuously for more than 16 hours, don't consider driving.