Why Our Body Needs Sleep


Sleep: an approach to the vital importance of resting adequately for your physical and mental well-being

Sleeping is one of the most important biological actions for the

functioning of the human body.

Sleep is a fundamental part of our daily routine, representing approximately a third of our time. Its quality and quantity are as essential to survival as are food and water. Just like animals when they hibernate, human beings without adequate sleep cannot form or maintain neural connections in the brain that allow us to learn and create new memories. Furthermore, the ability to concentration and rapid response are negatively affected in the absence of a restful sleep.

Sleep and brain functions

Various brain functions are impacted by sleep, including communication between nerve cells or neurons. Contrary to the belief that the brain is inactive during sleep, recent research suggests that remains surprisingly active. In fact, it has been discovered that during sleep, the brain performs a cleaning function, eliminating toxins accumulated while we are awake.

The biology of sleep

Although we all need sleep, the exact biological purpose of the dream remains a mystery. It affects virtually all tissues and systems of the body, from the brain, heart and lungs to metabolism, immune function, mood and disease resistance. Studies reveal that chronic lack of sleep or its low quality increase the risk of disorders such as hypertension, cardiovascular diseases, diabetes, depression and obesity. To avoid all this, there are apps that monitor the quality of your sleep.

Sleep, essential for our biology, triggers vital processes that nourish mind and body.

The anatomy of sleep

The hypothalamus and suprachiasmatic nucleus (SCN)

Located deep in the brain, the hypothalamus houses groups of nerve cells They act as control centers to regulate sleep and wakefulness. Within the hypothalamus is the suprachiasmatic nucleus (SCN), which receives information about the light exposure directly from the eyes, influencing our circadian rhythm.

The brain stem and REM sleep

At the base of the brain, the brainstem collaborates with the hypothalamus to control transitions between wakefulness and sleep. Sleep-promoting cells within the hypothalamus and brainstem produce a chemical called GABA, which reduces the activity of the alert centers in the hypothalamus and brain stem. During REM (rapid eye movement) sleep, the brain stem sends signals to relax essential muscles for posture and movement, preventing us from acting out our dreams.

The thalamus and the role of the senses

The thalamus acts as a relay for sensory information from the senses to the cerebral cortex. During most stages of sleep, the thalamus becomes silent, allowing us to disconnect from the external world. However, during REM sleep, the thalamus is active and sends images, sounds and other sensations to the cerebral cortex, forming our dreams.

In childhood and adulthood, sleep is a fundamental element for well-being.

The pineal gland and melatonin

The pineal gland, located between the cerebral hemispheres, receives signals from the SCN and increases the production of melatonin when it gets dark. Melatonin helps induce sleep. Those who have lost their sight can stabilize their sleep patterns by taking small amounts of melatonin at the same time each day.

The frontal lobe and deep sleep

The frontal lobe, part of the cerebral cortex, plays a crucial role in short term memory, thinking, planning and executing tasks. During deep sleep, brain waves slow down, allowing memory consolidation and restoration of cognitive functions.

The anterior basal system and the role of adenosine

Near the front and bottom of the brain, the previous basal system promotes sleep and wakefulness. The release of adenosine, a chemical byproduct of cellular energy consumption, supports the need for sleep. Caffeine counteracts drowsiness by blocking the actions of adenosine.

The amygdala and emotions during REM sleep

During REM sleep, the amygdala, a structure in almond shape related to the processing of emotions, becomes more active. This increase in activity may contribute to the emotional intensity of dreams during this phase.

Sleep stages and mechanisms

Sleep is divided into several stages, each characterized by unique patterns of brain activity and physiological functions. These stages repeat throughout the night in cycles of approximately 90 to 110 minutes. Understanding the phases of sleep provides us a deeper insight of how our body and mind experience this vital process.

Sleeping poorly at night has negative consequences on our daily lives.

Stage 1: transition to relaxation

The transition between wakefulness and sleep is smooth. Brain activity decreases, and muscles begin to relax. Often this stage lasts only a few minutes, and is easily interrupted.


Stage 2: light sleep

Brain activity is characterized by bursts of brain waves called sleep spindles and K complexes. The body prepares to enter a deeper sleep, but can still be woken up relatively easily.

Stage 3 and 4: deep sleep

These stages are known as slow wave sleep or delta sleep. Here the brain waves slow down significantly. Muscle activity decreases, and it is more difficult to wake up during these phases. It is during deep sleep that it occurs physical restoration and memory consolidation.

Stage 5: REM sleep

The rapid eye movement (REM) phase is when most vivid dreams occur. At the brain level, the activity is similar to when we are awake, but the major muscles are paralyzed, preventing us from acting out our dreams. This stage is crucial for the emotional processing and memory consolidation.

How much sleep do we need?

Sleep needs vary throughout life. Babies initially They sleep up to 16-18 hours a day, which is crucial for your brain growth and development. School-aged children and adolescents need about 9.5 hours of sleep each night to support their physical and cognitive development. Most adults require between 7-9 hours of nightly sleep, although this amount may vary depending on the individual.

However, Sleep quality is also essential. Factors such as stress, anxiety, and sleep disorders can negatively affect the sleep experience, even if the recommended hours are achieved.

It is advisable to sleep at least 8 hours a day.

Genes, neurotransmitters and sleep

Genetics plays a crucial role in regulating sleep. They have been identified several genes associated with sleep patterns, chronotypes (morning or evening preference) and sleep disorders. Additionally, neurotransmitters such as melatonin, GABA and adenosine They play key roles in regulating sleep and wakefulness.

Tips to sleep well

  • Maintain a regular schedule: Going to bed and waking up at the same time every day helps regulate your circadian rhythm.
  • Create an environment conducive to sleep: Make sure your room is dark, quiet, and at a comfortable temperature.
  • Limit screen exposure before bed: Blue light from electronic devices can interfere with melatonin production, making it difficult to fall asleep.
  • Avoid stimulants before bed: Caffeine and other stimulants can negatively affect sleep quality.
  • Do physical activity regularly: Regular exercise can improve sleep quality, but avoid intense exercise right before bed.

Why do we need sleep?

We need sleep because sleep plays a critical role in memory consolidation, emotional processing, physical restoration, and removal of brain toxins.

Back to blog