Sleep: A goodnight story
It’s the end of the day. You were busy all day long. Working, thinking, laughing, eating. Now it’s getting dark outside, and you are just watching some Netflix series. And start yawning. Your eyes are sleepy as hell. And now something strange happens...
You stand up from the couch. Go upstairs. Lay yourself on a square box with a fluffy topping. Close your eyes and then do nothing for around 8 hours…
Sleeping. It’s a daily ritual. Everyone does it. And not only humans, also other animals. When we don’t do this we might even die. When we do it, we dream some nonsensical stuff and start fresh the next day.
When you think of it, sleeping is really strange. Why do we need to do it? What’s the purpose of sleeping and dreaming? How do other animals do it? And what are the latest findings on sleep research? Let’s find out.
Do we die?
It was a cold and dark winter in 1963. In December at the end of the year 17-year-old Randy Gartner stopped sleeping. He stayed awake for 11 days and 25 minutes (264.4 hours). A record attempt in which he had mood changes, but seemed OK just before ending his record attempt and recovered well afterwards.
Sleep deprivation causes mood swings, cognitive impairments and even hallucination, paranoia and delusions. When not sleeping for days it can cause reasoning, memory and speech gets mixed up because of extreme fatigue. Most people fall asleep after staying 3 days awake.
But do we die? Studies show that almost nothing happens physically, but mentally there are a lot of negative effects. Thus, there is actual no evidence that we will eventually die without sleep. The only clue we have is from rat studies. Rats died after a certain time of sleep deprivation.
What’s the purpose?
The next question is what’s the purpose of sleeping? Couldn’t I write a book much faster when I wouldn’t sleep? Couldn’t I be more productive 8 hours a day? This is probably thought from a 24/7 economy perspective where you have artificial light, always have some food in the fridge, and you can shop online at 2 o’clock.
When you think that the night is really dark and there is not much you can do, it makes sense that you go into ‘saving’ mode. This saves energy. But a lot more is going on in our brains. Recent research has shown that during our sleep damaged nerves are being repaired. It’s also thought that new brain connections during the day are strengthened while sleeping and unimportant ones are pruned.
Thus, on an information level, information is better stored and maintained, while on a physical level nerves are repaired and the brain gets rid of toxic waste. Scientists are still finding out all the purposes of sleep. We already talked about energy conservation and the brain, others are:
- cellular restoration
- weight maintenance
- emotional well-being
At the end we do this a third of our lives, so it is probable that these factors together form an important purpose. Still it’s strange that we don’t learn a lot about this at school.
Another strange thing even with all these factors is why don’t just sleep, but go through several cycles every night (mostly three or four) like shown in the following diagram:
During the NREM phase we sleep the deepest. It’s during this NREM (non-REM) phase that the body repairs and regrows tissues, builds bone and muscle, and strengthens the immune system.
In the REM (Rapid-Eye-Movement) phase you can see the eyes moving under the eyelid. Beside that it is funny to see the eyes moving of someone that’s sleeping, it’s also the phase where most of the dreaming occurs. But outside the eyes your brain paralyzes your muscles, so you do not act out the dreams. That makes it even more curious what the role of dreams is.
In the dream things just are, but when you tell it to someone else there doesn’t seem any logic behind it. In a lot of cultures there were dream casters. Especially in the Native American cultures it was an important position in a tribe or society. In a sense Jung and Freud were somewhere in between the dream interpreters and scientists. And what do scientists know nowadays about dreams? Long story short, this is still not cleared area.
Sleeping at animals
All animals sleep. Sometimes it’s interesting to just watch them:
In general, it turns out that small animals sleep more than large animals. For example a mouse sleeps more than 6 times as much as an elephant. It also depends on energy conservation. That’s why lions for example sleep a lot. Cats at home sleep around 16 till 18 hours. And we envy them…
Above you can see an infographic with the sleeping habits of several animals. Thus even an Octopus or snail sleeps. Some, like horses, can sleep even standing. Sloths, who are day sleepers, actually sleep not that much (10–15 hours). An albatross can sleep while flying above the ocean. More on the sleeping habits of other animals can be found in this article:
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One animal that has interesting sleeping habits are dolphins. They sleep with one brain half, while the other half is active. This is also the reason why their brains are big and the left and right brain hemispheres are separated from each other.
There is still a lot we don’t know about sleep. Fortunately now sleep research is a central field to study. And there is still a lot to find out. In the leading journal “Sleep Health: Journal of the National Sleep Foundation” just 5 years ago the guidelines how much sleep we need, changed based on 320 studies. The current guideline is:
- Newborns (0–3 months): Sleep range 14–17 hours (before it was 12–18)
- Infants (4–11 months): Sleep range 12–15 hours (before it was 14–15)
- Toddlers (1–2 years): Sleep range 11–14 hours (before it was 12–14)
- Preschoolers (3–5): Sleep range 10–13 hours (before it was 11–13)
- School age children (6–13): Sleep range 9–11 hours (before it was 10–11)
- Teenagers (14–17): Sleep range 8–10 hours (before it was 8.5–9.5)
- Younger adults (18–25): Sleep range is 7–9 hours
- Adults (26–64): Sleep range is 7–9 hours
- Older adults (65+): Sleep range is 7–8 hours
The question remains on the origin of sleep. It seems that even animals without a nerve system and without brain, have some form of sleep. A recent study published at the beginning of 2021 suggest that “many sleep-related mechanisms developed before the brain and may have been conserved during the evolution of central nervous systems”.
One thing remained true, sleeping is healthy. Especially for mental health. Poor sleep can lead to depression in adolescents and emotional instability at kids. Especially true for teens is that sleep loss can cause learning problems. This is all due to that sleep can strengthen or weakening memories.
For teens not only learning can be improved, also coping with social stress. Much more in general deep sleep can relief stress: “anxious brain is deep sleep, also known as non-rapid eye movement (NREM) slow-wave sleep, a state in which neural oscillations become highly synchronized, and heart rates and blood pressure drop”.
Recent findings have clues that sleep deprivation can also cause physical damage. Interesting that it even can be a risk factor getting Covid-19. Other research found links with higher risk of heart failure, higher risk at dementia and obesity.
Sustaining good sleeping habits is thus important for a goodnight sleep. Well-known is the negative impact of blue light in our mobile and computer screens. Recommended is to avoid looking at bright screens beginning two to three hours before bed. Lesser-known is that our gut microbes are one of the keys to a goodnight sleep: “Changing which microbes are in the gut by altering diet has the potential to help those who have trouble sleeping.”
Final goodnight thought
It’s interesting how something passive and often forgotten thing as sleep, is linked to so many things in our lives. A good diet and avoiding blue light before sleep can cause better sleep, which in turn can improve learning, our mental being and coping with stress. Sleep well.
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