We do it every night; we lay down in bed, close our eyes, the external world slowly varnishes, and we begin to fall asleep and drift into unconsciousness. While it might seem like everything slows down and stops, a lot is going on inside our brains. Sleep was believed to be a passive state for a long time, but neuroscientists now distance themselves from this thesis. From the outside, you can barely distinguish whether a person is really sleeping or just pretending to do it, but with an EEG instrument, you can easily define the state of sleeping by looking at the brain activity. But what happens during sleep, and is it true that it actually affects our creativity?
To clarify this, we have to take a look at the different phases of sleep. In total, there are four stages, and the entire sleep cycle repeats itself four to seven times a night. The first three stages are so-called non-REM stages, and the last forms the REM sleep; what this exactly means will be explained later on. So let’s start with the first stage, the “dozing off” stage, when the body has not fully relaxed yet, but brain activity starts to slow down. This phase is approximately one to five minutes long and marks the transition from wakefulness to sleep. In this stage, it is easy to wake someone up. This gets harder in the second phase: the light sleep phase, which lasts around twenty to sixty minutes. The temperature drops, the heart rate decreases, the muscle become relaxed, and we begin to breathe slower. After this, we are ready to enter stage three, also known as deep sleep. This is where things get really interesting. In this phase, the body starts to repair itself physically. But not only that, during this phase of sleep, our brain consolidates and edits our memories, like general knowledge, facts or statistics, personal experiences and other things we have learned in a way that after sleep, they are in a different structure and order. Through this order process, we are capable of recognising hidden structures. So there might be a truth in the german saying to “sleep the night on it” whenever you have to make an important decision, or in the Italian version, “the night will bring you advice”, since during sleep our brain is busy forming, organising, and storing all our memories and impressions we gained throughout the day. In this phase, the heart rate and blood pressure decrease like in all the others.
This changes in the fourth phase, during REM sleep. Even though it is the deepest phase of sleep, scientists record an increase in heart rate and blood pressure as well as an uptick in brain activity. Looking at the brain activity, it actually has more similarities to being awake than with the deep sleep phase. This phase is also known as paradoxical sleep because the brain is very active, but the body remains completely still, and many of our muscles become temporarily paralysed. This is important for keeping us in place while we sleep and prevents us from kicking our legs as we dream about running. Just our eyes are quickly moving, what’s called rapid eye movement, and that is where this phase got its name from. As already mentioned, dreaming in this phase is not uncommon. Since its discovery, REM sleep has been closely associated with dreaming. If you wake someone up during sleeping in this stage, 80% of the people can give some dream report. Furthermore, it is proven that dreams in this phase tend to be more vivid and richer in imagination than the ones in other phases that also occur but are just not as intense. Regarding the length, REM sleep comes about after ninety minutes; during the first period, it only lasts ten minutes but becomes increasingly longer with later periods. Like deep sleep, this period is essential to cognitive functions like memory, learning and creativity.
But not only our brain is active. In the first half of the night, growth hormones that support relaxation and renewal of bones, muscles and inner organs get released, and our metabolism works at full pace. Also, the immune system is working. During sleep, there are more immune cells and antibodies in our blood, which is the reason why it is so important to get enough sleep while you are sick. One last but very essential process is a disposal system. Whenever chemical processes occur in any part of the body, we get the product we need, but at the same time, useless “garbage” is created for which the body has no use. Usually, the disposal of these garbage takes place via the lymphatic system, but the brain and the central nervous system in general are not directly connected to it. Nevertheless, there is a lot of chemical trash produced in the brain. This trash can only enter the lymphatic system through the brain tissue, and now comes the surprising point, this waste disposal in the brain happens four times more quickly during sleep than in the awake state.
Knowing all the processes happening at night, it becomes obvious why sleep is essential; it allows the brain and body to recuperate and develop. On the other hand, not getting enough sleep can have severe consequences on our thinking, our emotions and our physical health. Among the problems caused by sleep deprivation are limited capacity for learning and focusing, solving problems, being creative, recalling memories or information, making rational decisions and controlling your emotions and behaviour. Additionally, it puts us at a greater risk for heart disease, inflammation, high blood pressure, overweight, and diabetes. In general, it can be said that it reduces our overall quality of life. Even after only one night of bad sleep, we begin to crave sweets & fatty foods more, and our mood suffers. One thing that can become really dangerous, too, is the shortened attention span. Scientists found that moderate sleep deprivation has similar effects as alcohol consumption on the attention span level. Now just imagine traffic full of tired drivers unable to react as quickly as they have to.
But how can we improve our sleep?
ASMR videos, CBD oils, thousands of meditation podcasts, mattresses start-ups, therapy blankets and lavender diffusers, the market is full of products promising to help us with our sleep “hygiene” – a word that has only recently become a trend. Sleeping problems are not uncommon; many people suffer from them, and in their desperation, they are willing to try out anything that claims to help them sleep. While the effectiveness of the products mentioned above is not always scientifically proven, there are some common tips that are probably known by all of us which actually help. Some of them are having a small ritual before going to bed, which signals our body its time to sleep now and eliminate noise and light disruption. Avoiding blue screen lights right before bedtime is also crucial since it confuses our brain and prevents it from releasing melatonin, which is only released in the dark, which is why it’s also sometimes called the Dracula hormone. Another thing that is commonly believed to help us fall asleep is alcohol. While it is true that it helps to fall asleep, it decreases our REM sleep phases and causes us to wake up more often in the second part of the night.