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Why We Sleep: The New Science of Sleep and DreamsI just finished reading
the book about sleep and, as usual, want to share my findings from the book with you. Often there is a perception that sleep is something that is NOT that important, it is something that is stealing our time, something that prevents us to live our life more hours. It turns out that it is...not true.
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Is sleep a time when we relax? No, sleep is the time when our brain works and, sometimes, works as hard as if we are awake. We need sleep to process what we had today and prepare ourself for being awake the next day. So we can ... sleep again. Author also slightly asks the question — what if we live to sleep and not otherwise? Because of us as biological creatures sleep is one of the best states, why do we bother to awake?
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Why do we want to sleep? First — we have suprachiasmatic nucleus in our brain. This thing tracks light and sets our circadian rhythms, so that we live within the 24-25h cycle. This rhythm gives us the "awake" urge. Secondary — when it is getting darker our brain starts to release melotonin. This way our body knows that, in principle, we can go sleep. Third — when we are awake we accumulate adenosine. When we have enough of it, than we want to sleep.
Together — when our circadian rhythm tells us that we do not need to be awake, melotonin tells that we may sleep and adenosin makes us sleepy, than we want to sleep.
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Coffee, does it make me awake? Coffee does not make you awake, it just blocks those receptors that feel adenosin. So that you do not feel the sleep pressure. But when the effect from the coffee dissolves, then you still will feel the same adenosine. Half-life of the coffee is 4h. That means, that if you drink coffee at 4 p.m., that it will still affect you at the time you go to bed. Be careful taking coffee after midday, it might affect your sleep.
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What happens when I sleep? We sleep in 1.5h cycles. There are three phases — deep sleep (NREM), light sleep and REM (rapid eye movement). At the start of the night we experience more NREM sleep, closer to the awake time — more REM. All phases are needed.
NREM — during this phase our brain distributes what we have learned today (and not only) through other parts of the brain. This is why sleep is important when we study. Even more, based on our perception our brain knows what it should remember and what not. After this phase our operatin memory is fresh and we can operate the next day.
REM — our brain bumps into each other the information we already know. This way we can derive new ideas. We see dreams in this phase. This phase is very important for the emotional development and processing of the emotions. Our brain reviews the emotional experience of the day, removes the emotional part and writes it as autobiographical memories. This is why the next day we have less pain thinking about the loss of our favorite football team.
light phase — nothing specific is said, but our brain also cleans itself up from the chemicals from yesterday (glia), so that the next day we feel ourself fresh.
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When we are sleep deprived. In case you do not sleep 7-8h daily you ARE sleep deprived. When we have not enough sleep — everything is bad. We control our emotions worse, we take less initiative, we drive worse, our immune system underperforms. There is another trick, people just do not feel that they underperform, they think they are fine.
It is proven, that you can not sleep it over on the weekends. I mean, you sleep <7h daily, and then sleep 10h on the weekend. It will not compensate your sleep deprivation. We, we as a species, have to sleep 7-8h daily to be in top shape.
There is no hack to sleep. Sleep is integrated very deeply to our biological body. We have to sleep 7-8h. Sleep deprivation leads to the illnesses and all the bad things.
