The functions of sleep discovering the mystery of the night

The dream is an essential biological function that all human beings experience throughout our lives. Despite We spend approximately one third of our lives sleeping, There is still a lot of mystery around the functions of sleep and its benefits for our health and well -being. The fact that the dream has persisted throughout evolution, shows us that it is functionally important. But the nature and functions of the sleep are still subject to many discussions and different hypotheses have been proposed that can become complementary to each other.

In this article, we will explore some of the theories and scientific discoveries that have emerged in recent years on the functions of sleep and its impact on our daily lives.

Content

• Sleep functions
  • 1. Energy conservation
  • 2. Body recovery and repair
  • 3. MEMORY CONSOLIDATION AND LEARNING
  • 4. Emotional regulation
  • 5. Cerebral waste elimination
  • 6. Maintenance of the immune system
• What happens when we don't sleep?
  • Bibliographic references

Sleep functions

Sleep functions are essential for our physical and mental health. Ensuring to have enough quality of quality is essential to maintain a healthy and balanced life. Below you can see all the functions that sleep:

1. Energy conservation

When we sleep we spend less energy, since when we are in the sun (dream dream), there is one decrease in blood pressure, heart rate, respiratory rhythm, muscle tone, body temperature, etc. All this suggests that the possible role of sleep would be the conservation of energy.

The idea that the dream strength to rest is supported by the fact that small mammals sleep much longer, proportionally, with respect to large mammals. They are animals with a great demand for energy for thermoregulation and locomotion, but with few reserves.

But how do we explain that during the dream REM there is a high metabolic expense? F. Snyder in 1969 suggested that ReM dream could be a period in which there is more brain activation, in case you have to be alert to possible dangers. Some species, to avoid possible dangers that involve the fact of entering into sleep, have developed a different sleep pattern for each cerebral hemisphere. For example, Delphin Tursiops truncatus, in which each hemisphere sleeps separately.

2. Body recovery and repair

One of the best known functions of sleep is its role in the recovery and repair of the body. During sleep, our body performs various functions, such as fabric repair, release of growth hormones and the elimination of waste products. These processes are crucial to maintain good health and prevent diseases.

The metabolic rate during sleep represents 15% of the one we keep in vigil. The reduction of metabolic processes are also related to the characteristic of body temperature.

However, sleep deprivation studies have not provided convincing evidence that the dream is necessary to maintain a normal functioning of the organism, since in these studies there is no important stress response of the organism. In addition, on the one hand, sleep deprivation does not hinder people's ability to carry out physical exercise; And on the other, we have that physical exercise does not make the person sleep more hours (although he may sleep before).

He dream would be a process in which different anabolic processes are given that try to compensate for the physical and emotional wear of vigil; This would be a vital physiological need, we sleep because we need to rest and regain strength. The fact that during some periods of sleep there is a hormone release, could support this hypothesis.

3. MEMORY CONSOLIDATION AND LEARNING

The dream also plays a fundamental role in the consolidation of memory and learning. During the dream, Our brain processes and organizes the experiences and knowledge acquired throughout the day. This allows our mind to create more solid and lasting connections between different concepts, which facilitates the memory and understanding of new information.

Humans show few physiological deficits after some days of deprivation; instead, Yes, intellectual abilities are altered. After a period of sleep deprivation may appear perceptual and hallucinations alterations.

After prolonged sleep deprivation periods, the subjects show a greater amount of REM dream and, above all, of sun.

The dream seems necessary for the normal functioning of the brain.

Many studies, especially with animals, have studied the relationship between REM dream and Learning and Memory Processes, especially from the following observations:

• Existence of cortical deincronization
• Theta hipocampal rhythm appearance
• Increased blood flow
• Increase in protein synthesis
• A certain phylogenetic correlation between REM dream and the learning ability of species.
• Existence of significant correlations between REM dream and the learning capacity and memory of the subjects.
• Activation during Sleep Rem of structures with a strong affective component of memory, such as the tonsil.

In an experiment conducted in 1994 by Karni and others, it was observed that the deprivation of sleep ReM after a learning session implied a poor retention of the task the next day. On the other hand, the deprivation of the sun did not produce these deteriorating effects.

In another experiment it has also been shown that the brain patterns that are recorded in the hippocampus of rats that during the day have traveled a maze (they were rewarded with food), they reproduce very accurately when the rats sleep. This relationship becomes so precise that researchers could say in which part of the maze would the animal be if it was awake.

Some authors, like F. Crick, believe that ReM dream would allow the memory of the memory of those information that is not useful to us, that we do not need to retain. On the other hand, other authors believe that this would be a function of the sun. It may also be that each period contributes differently to learning and memory processes.

4. Emotional regulation

Sleep and emotional regulation are intimately related, and a good break is essential to maintain optimal emotional health. During sleep, the brain processes and organizes the emotional experiences lived during the day, allowing better understanding and adaptation to emotional stimuli. Lack of sleep, on the other hand, can have a negative impact on our ability to regulate our emotions and manage stress. Next, some key aspects of the relationship between sleep and emotional regulation are described:

1. Emotional processing during sleep: During sleep, especially during the fast movement sleep phase (REM), the brain processes and consolidates the emotional experiences of the day. This process helps to reduce the intensity of negative emotions and integrate them more adaptively in our emotional memory. In addition, REM dream is essential for the processing of emotional information and the formation of stable emotional memories.
2. Impact of lack of sleep on emotions: Lack of sleep can alter emotional regulation and increase susceptibility to negative emotions such as irritability, anxiety and sadness. Studies have shown that sleep deprived people tend to experience greater emotional reactivity in the face of negative events and a lower capacity to enjoy positive experiences. They can also have more difficulty managing stress and emotionally recovering from adverse situations.
3. Sleep and mental health: The quality and quantity of sleep are closely related to mental health. The chronic lack of sleep has been associated with an increased risk of mood disorders, such as depression and anxiety. Early sleep problems can be key to preventing or treating these disorders.
4. Sleep and emotional decision making: Lack of sleep can also affect our ability to make emotional decisions and properly evaluate social situations. People deprived of sleep can have difficulty recognizing emotions in others and to correctly interpret emotional signals in their environment, which can result in less empathy and social skills.

5. Cerebral waste elimination

The dream plays a fundamental role in the elimination of brain waste, which is crucial to maintain the health and proper functioning of the brain. During the dream, especially in the sleeping phase of slow waves or deep sleep, the brain is actively dedicated to eliminating toxic substances and waste products that accumulate during the hours of vigil.

A key system in this cerebral cleaning process is the glinphathic system. This system, discovered in 2012 by DRA. Maiken Nedergaard and his team, consists of a network of perivascular channels where the cerebrospinal fluid circulates. The glinphathic system works as a "cleaning system" that eliminates waste products and toxic substances from the brain, including beta-amyloid and TAU proteins, which are linked to neurodegenerative diseases such as Alzheimer's.

The operation of the glinphathic system is more efficient during sleep due to several factors:

1. Changes in extracellular space: During sleep, the extracellular space of the brain expands, which allows the cerebrospinal fluid to circulate more easily and effectively through the perivascular channels of the glinphathic system.
2. Decrease in neuronal activity: The decrease in brain activity during deep sleep reduces the energy demand of the brain, which allows more energy to be dedicated to the processes of cleaning and elimination of waste.
3. Changes in glial cell activity: Glial cells, such as astrocytes and microglia cells, are involved in the brain cleaning process. During sleep, the activity of these cells is modulated to facilitate the elimination of waste.

6. Maintenance of the immune system

The dream also has an impact on our immune system. Lack of sleep weakens our defenses and makes us more susceptible to infections, diseases and chronic disorders. During sleep, our body produces proteins called cytokines, which are crucial to combat infections and maintain a strong immune system.

The relationship between sleep and the immune system is based on several aspects:

1. Cytokine production: During sleep, especially in the phases of deep sleep, the body produces proteins called cytokines. These cytokines, such as interleucin-1 (IL-1) and the tumor necrosis factor Alfa (TNF-ALFA), have anti-inflammatory properties and help regulate the immune response. Cytochin production is essential to combat infections, inflammations and other diseases.
2. Immunological cell activity: The dream also influences the activity of different cells of the immune system, such as T lymphocytes and natural murderous cells (NK). These cells play an important role in the immune response and defense against infections and diseases. During sleep, the activity of these cells is modulated to optimize immune function.
3. Balance between the nervous system and the immune system: The dream helps maintain an adequate balance between the nervous system and the immune system. Lack of sleep can cause an increase in stress and activation of the hypothalamus-hypophysis-supranal axis (HPA axis), which can lead to a decrease in immune function.
4. Recovery and repair: The dream allows the body to recover and repair itself, which is essential to maintain a healthy immune system. During sleep, the body carries out various cellular repair and regeneration processes that are crucial to maintain a strong and efficient immune system.

Lack of sleep, on the other hand, can weaken the immune system and increase susceptibility to infections, diseases and chronic disorders. Studies have shown that lack of sleep is associated with a reduction in cytokine production and a decrease in the function of immune cells. In addition, sleep deprivation can increase the risk of infections, such as colds and flu, and negatively affect the body's ability to combat diseases and recover from them.

What happens when we don't sleep?

The different experiments with sleep deprivation indicate that this must have an important role in the body homeostatic system, temperature control and balance of the immune system and that probably participates in cognitive functions.

For example, it has been observed that private sleep rats for 3-4 weeks end up dying; If they are deprived of the ReM, they survive twice as much time. At the beginning of deprivation they eat more than normal, it is supposed to not lose weight, but they still do not recover caloric balance, then lose control of temperature and also weaken the immune system.

In any case, the fact that we find the dream as a phenomenon in all species of mammals and birds, indicates that, at least in part, It is physiologically necessary.

The effects of sleep deprivation do not seem to be as drastic in humans as in animals. One of the most spectacular cases described in humans is the case of a boy who spent eleven days without sleep. The symptoms that appeared progressively were bad mood, dizziness and nausea, memory problems, feeling of tiredness and tremors. When he decided to sleep, he did it for fifteen hours in a row, then he held twenty -three three hours awake, to go back to sleep for ten hours. Against any forecast, there were no side effects and after a week its sleep rhythm was totally normal.

How long can a sleeping person spend?

What is safe, is that the dream seems that physiologically is necessary to survive and for a good brain functioning.

Bibliographic references

• Alcántara-Montero, a., & Alvaro, P. K. (2017). The importance of sleep: health repercussions. Las Condes Clinical Medical Magazine, 28 (5), 605-615.
• Diekelmann, s., & Born. (2010). Memory in sleep: consolidation of memory during sleep. Neurology Magazine, 50 (2), 103-110.
• García-García, f., Drucker-Colín, r., & Fernández-Mas, R. (2010). Sleep and synaptic plasticity. Mental Health, 33 (4), 299-306.
• Guzmán-Marín, r., Soto-Rodríguez, s., Rodríguez-Velázquez, e., & Arias-Carrion, or. (2012). Dream and Dream Functions Rem in memory. Mental Health, 35 (5), 359-364.
• Xie, l., Kang, h., Xu, q., Chen, m. J., Liao, and., Thiyagarajan, m.,… & Nedergaard, M. (2013). The dream drives the metabolic clearance of the brain. Science, 342 (6156), 373-377.
• Besedovsky, l., Lange, t., & Born. (2012). Sleep and immune function. Pflügers Archiv - European Journal of Physiology, 463 (1), 121-137.