© Andrea Piacquadio/Pexels
During Antiquity, philosophers like Theophrastus and Plato were already interested in sleep. However, the latter nevertheless remained very mysterious until the 20th century. This is when the electroencephalogram was developed, which allowed scientists to better understand its role. It is a fundamental pillar of our health and still remains one of the most fascinating and complex phenomena in human biology.
Far from’ being a simple state of rest, it is constituted of a series of precise neurological and physiological events which remain essential to our survival. Extremely rare cases exist, like that of Paul Kern. During the First World War, he received a bullet in the head which deprived him of part of his frontal lobe. Following this injury, he never slept again for 40 years. A mystery that still remains unsolved to this day.
Sleep, an indispensable ally
When we return In the sleep phase, our brain is far from being inactive. In reality, he is even engaged in a rather intense activitymemory consolidation. It organizes and strengthens neural connections in order to transform the sum of information learned during the day into lasting memories. This cerebral phenomenon occurs mainly during deep and paradoxical sleep (we will return to this later).
Fundamental for learning and memorization, this phase allows our brain to correctly organize new knowledge, to process and store experiences without interference.
< p>According to the Foundation for Medical Research, not getting enough sleep, even if it is not regular, already carries risks. “ After too short a night, there are immediate risks: mood disorders, reduced attention and alertness problems. In the medium term, significant irritability can set in, a risk of depressive syndrome and above all learning difficulties » she explains on her site.
Of course, sleep also serves to the body's energy recovery . Paradoxically, this energy saving is not as significant as one might think. Compared to a subject in a passive wakeful state, sleep reduces the body's energy consumption by between 5 and 11%. It's not much, but this energy optimization strategy is essential.
Another fundamental aspect of sleep is its impact on the immune system. When we sleep, a natural process of repair and strengthening of defenses takes place, which equips us to fight infections and diseases more effectively by optimizing the body's immune response.
This is also when our body adjusts the production of certain hormones essential for life, such as cortisol (physical and emotional stress) or ghrelin and leptin (regulation of hunger).
L’complex architecture of sleep phases
If we were to compare sleep to a piece of music, it would be conducted by two different conductors and could not begin to be played without them. The first is the biological clock, which schedules our sleep at a certain time of the day, usually at night. The second is called sleep pressure, which corresponds to the gradual accumulation of the need to sleep as we stay awake.
Sleep is a very organized process, composed of several distinct cycles, which we go through several times during a complete night.
The first cycle is called light sleep (Stage N1 and N2), which corresponds to the transition phase between wakefulness and deeper sleep. It is this cycle that accounts for the majority of total sleep time. During this phase, the muscles begin to relax, the heart rate and breathing rate drop. Body temperature also drops: for the brain, this is the signal that it is time to sleep. At this time, it is still very easy to be awakened by external stimuli.
Next comes deep sleep (stage N3) , also called slow wave sleep. This is the most important cycle for physical recovery and memory consolidation. When we are in this sleep phase, the body repairs itself: repair or regeneration of tissues, construction of muscles and bones, and strengthening of the immune system. As its name suggests, it is much more difficult to be awakened during this cycle.
The paradoxical sleep or REM (Rapid Eye Movement)is characterized by rapid brain activity, almost similar to that of the waking stage. The muscles are paralyzed, involuntary eye movements are rapid and it is during this phase that most dreams take place. This cycle plays a key role in processing the experiences of the day that has just passed and in consolidating emotional memory.
All these cycles repeat several times over the course of an entire night, and usually last between 90 and 120 minutes each. On average, we go through 4 to 6 sleep cycles each night.
Sleep can be compared to one of the architects of our body, working silently to make it work optimally. It regulates and harmonizes the different systems of the body; physical or psychological; and ensures our overall well-being. However important it may be, “ between 30 and 50 % of adults in France declared the presence of a sleep disorder » according to Public Health France. A condition affecting women more than men.
- Sleep plays a key role in the proper functioning of our body .
- It consolidates memory, strengthens our immune system, allows the body to recover and regulates the production of hormones.
- A night is broken down into several sleep cycles, each with different characteristics.
📍 To not miss any news from Presse-citron, follow us on Google News and WhatsApp.
[ ]