On average, adults need 7-8 hours per night, while children can sleep up to 10-12 hours a day. Having said that it is also true that the need for rest is an individual characteristic. The transition from wakefulness to sleep is regulated by a timing that changes from individual to individual and even in the same person it can vary according to age and time of life. The first rule to sleep well is precisely to identify your needs and then do everything to respect them, because the variations (early awakenings or long nights without sleep) constitute an alteration of the natural balance and can lead, in the long run , to suffer from sleep disturbances and insomnia.
What happens during sleep
During sleep the body slows down its physiological functions. The temperature drops, the metabolism slows down, the blood pressure stabilizes and the tissues regenerate. Good hours of sleep also allow you to give new life to your memory and make us more alert and attentive. If it is true that afternoon naps can be a valid support, it is essential to sleep well at night. Our body, in fact, is programmed to sleep right at night, which is why when we are late for various reasons and we believe we can recover „lost“ sleep perhaps on the weekend, this does not actually happen. Indeed, according to some research, sleeping too much on the weekend would even endanger health.
American researchers have studied and observed that the predisposition to wake up early or not to sleep at night would lie in the genetic makeup of each individual. This is what they say in a study published in the journal Nature Communications, which reads that there are 15 regions of DNA that would be connected to the chronotype, that is, to the tendency of human beings to be more active during a particular moment of the day.
Human studies have shown that rest serves, among other things, to consolidate memory and improve learning, but there must be something even more important for a function that in fact is primary and indispensable such as feeding or drinking. Research published in the journal Science explains that perhaps the main purpose of sleep is to allow the brain to „clean up“ by eliminating the waste produced by brain cells; moreover, some neurological pathologies could depend on the lack of «washing» of toxic proteins during the night.
The research was conducted by visualizing the brain activity of awake and sleeping mice, focusing mainly on the so-called glymphatic system: these are ways, identified by the authors themselves, that would be responsible for cleaning the nervous system by disposing of „metabolic waste“ of the brain. In fact, although it is one of the most delicate organs in the body, it is devoid of the lymphatic vessels that everywhere, in the rest of the body, are used to remove waste. „We noticed that the glyphatic system is ten times more active when mice are asleep – explains Maiken Nedergaard, head of the study and director of the Laboratory of studies on glial diseases at the University of Rochester -. Some brain cells, probably the glial ones that serve to keep neurons viable, get smaller during sleep: the space between these cells increases by 60 percent and this allows the entry of a greater quantity of fluids that help drain toxic substances and waste. „
It is a vital function for neurons, but it seems that it is not possible to perform it while the brain is awake: „It seems that a lot of energy is needed to pump fluids into the brain and clean it, and this may be incompatible with normal cognitive activities – says the expert -.
After all, in a house you can have a party and you can do the cleaning, but these two activities cannot be performed simultaneously: it is as if the brain had to choose between two possibilities, awake and alert or asleep and intent on clearing the field from waste ‚.
The researcher notes that having confirmation of these data in humans will be relatively simple, in fact it will involve carrying out magnetic resonance imaging studies in awake or asleep volunteers; the implications, however, could be significant, because a poor brain purification capacity due to inadequate sleep could contribute to the appearance of neurological pathologies characterized by the uncontrolled increase in metabolic waste. In some diseases such as Alzheimer’s or Parkinson’s, for example, many toxins are produced and if the brain cleansing mechanisms do not work well the situation could further worsen. For the moment they are only assumptions, which however open new paths to research.
Confirmation of the usefulness of rest for the brain also comes from a study by the Swedish KTH Royal Institute of Technology: according to the researchers, a spare brain is doing important work because it is storing the data it deems necessary by discarding what it does not It serves. The problem is that today we are constantly bombarded with information: it happens by surfing online and, according to the expert Erik Fransén, this is having a harmful effect on our memory capacity.
„When we communicate we need working memory, the short-term one: it is the one that helps us to filter information and decide which to use to communicate, but it is a limited resource that can only contain a few data at a time – explains Fransén -. When we surf the web, however, we infuse concepts with short-term memory and our ability to process them, choosing what to hold back, it begins to lose blows.
Furthermore, when we try to store too much in short-term memory we are also stealing from the brain the time and resources it needs to do the cleaning, transferring what really matters to long-term memory. Staying disconnected from the Internet for a while is good, in other words „. In short, time spent in idleness or sleeping is not wasted time: the brain works hard for us even in these situations and sleeping little while always connected to the web would seem to be the fastest way to go haywire.