This story is about to fall asleep! No seriously. The science of dream and recovery provides new insights into what healthy sleep looks like. And why we should avoid blue light.
Almost every night of our lives, we undergo an amazing metamorphosis. Our brain fundamentally changes its behavior and purpose. It drives down our consciousness. For a while, we are almost completely paralyzed. Sometimes we think we can fly. We sleep.
Around 350 BC Aristotle wrote an essay “About sleeping and waking”. In it, he wondered what we actually do and why. For the next 2300 years, no one could give a satisfactory answer. Then, in 1924, the German neurologist and psychiatrist Hans Berger invented the electroencephalograph, which records the electrical activity of the brain. In order for the changed sleep from philosophy to science. Everything we learn about sleep underscores its importance to our mental and physical health.
The majority of Germans sleep seven hours or less per night on a normal working day, which is on average two hours less than in the 19th century. This is mainly due to the spread of electric light, followed by televisions, computers, and smartphones. In our restless society, we often regard sleep as an adversary: a state that prevents us from being productive. On a good night, we glide through different stages of sleep four or five times, each with a specific value and purpose.
Stages 1 and 2 – We fall asleep and our brain starts its processing process
The human body does not like to dwell between two states. We prefer to be awake or to sleep. When our biorhythm is docked to the cycle of daylight and darkness, our pineal gland produces melatonin in the brain base, which is “evening!” signals, – then our neurons go to sleep.
Scientists call this stage Stage 1, the shallow phase at the beginning of sleep. It may take five minutes. After that come from the depth of the brain a lot of electrical sparks. They bombard the cerebral cortex. These half-second salvos, visible in the EEG as so-called sleep spindles, indicate that we have entered stage 2.
It has long been assumed that our brain is less active during sleep – in fact, it is only active differently. The Spindles of Stage 2 will eventually become less. The little bit we’ve seen from the outside world is now completely lost in the dark. We dive into a deep sleep.
Stages 3 and 4 – We enter a deep sleep that is especially important to our brains
Sleep is life support: a living creature, no matter how big or complex it is, cannot run full steam 24 hours a day.
During deep sleep, our cells produce most of the growth hormones that supply bones and muscles. Sleep also seems important for a healthy immune system, body temperature, and blood pressure. Usually, we do not dream at this stage. It could be that we do not even feel pain. We stay in stage 4 for a maximum of 30 minutes, then the brain gets out and we usually go back into the waking state. Even healthy sleepers wake up several times during the night, but most do not notice it.
As the US health authorities know, more than 80 million adult US citizens suffer from chronic sleep deprivation. About one-third of humanity suffers from at least one diagnosed sleep disorder in the course of life, from chronic insomnia to sleep apnea and restless leg syndrome.
But insomnia is by far the most common problem. But if sleep is a natural phenomenon that has been refined over millions of years, why do so many people have such problems with it?
Evolution, like all living beings, has provided us with sleep that is flexible and easy to break in timing. In the brain, a control system is active in all sleep stages. It can wake us when it registers danger. The only problem is that this age-old, inborn wake-up call is constantly being triggered by situations that are not life-threatening: the fear of testing, financial worries, or the car alarm system in the neighborhood.
Those who sleep less than six hours regularly at night have an increased risk of developing depression or psychosis or having a stroke.
REM – We dream, regulate our mood and consolidate memories
Rapid Eye Movement or REM sleep was discovered in 1953 by Eugene Aserinsky and Nathaniel Kleitman at the University of Chicago. The inconspicuous pattern on the early EEGs meant that this phase was initially considered a variant of stage 1. But the characteristic rapid eye movements and the associated swelling of the sexual organs made it clear: the lively dreaming happens in this phase.
Overall, REM sleep in adults accounts for about one-fifth of the total rest period. In REM sleep we are practically crazy every time. Some sleep researchers say that dreams are a psychotic state – that is hallmarked by hallucinations and delusions. Even if you can not remember a single picture after waking up, you’re dreaming. Dreams are falsely mistaken for fleeting flashes. In fact, they cover almost the entire REM phase, usually about two hours a night.
When We Are Alive, the Brain is Busy But when we sleep and enter the REM stages, this most sophisticated and complex tool in the world can finally do what it pleases. It is dreaming. “Sleeping is good for the brain and the body, but also an experience,” says Michael Perlis of the University of Pennsylvania. “REM sleep is perhaps the element that makes us the most human.”
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