Sleeping little: what are the consequences?

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Joe Dispenza

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Sleeping little: what are the consequences?

Cognitive, emotional and physical disturbances have been attributed to the habit of little sleep. Resting for the necessary hours must be our priority.

Last update: 16 March, 2020

Little sleep has become a habit for many teenagers and adults. When the lifestyle is saturated with stimuli, with impatience, with a hectic need to do everything, basic needs, such as sleep, end up altering.

At the same time, changes in daylight hours or shifts and constant access to technology are encouraging this habit.

The consequences of an altered sleep manifest themselves on different levels, namely emotional, cognitive and physical, to the point of creating new ailments such as insufficient sleep syndrome. This is ultimately a mistake in managing our daily priorities.

The mechanism of sleep

Sleep is a basic physiological state and involves a lowering of alertness and consciousness. The aim is to develop processes of integration of brain activity and modify the physiological mechanisms of our body. It is governed by the circadian cycle, in which a state of wakefulness and one of sleep alternate.

Sleep is composed of two main phases that always follow each other in the same order. The first stage is Non-REM sleep, characterized by the absence of rapid eye movements. It is divided, in turn, into four moments:

  • Not REM1: sleep is light, it is easy to wake up and the perception of stimuli, internal and external, still exists.
  • Not REM2: the sensory access of our body is blocked, the muscles relax and the heart rhythm slows down. Brain waves begin to decrease allowing the brain to calibrate its activities.
  • Not REM3: brain waves continue to decrease, sensory block is stronger. Increases the production of growth hormones.
  • Not REM4: together with the previous stage, it is the moment in which sleep is deepest. Delta waves predominate.

The second stage of sleep is called REM, which is characterized by the presence of rapid eye movements.

In this phase, muscle tone decreases; the respiratory and heart rhythms are irregular. It is the time of sleep when the brain is most active and produces lucid dreams with a common thread.

Brain activation and the habit of little sleep

In research using brain imaging techniques, it has been observed that a decrease in the time spent sleeping causes an overall reduction in cognitive activity.

This occurs mainly in the prefrontal cortex and in the parietal lobe. The tests have focused particularly on verbal activity and is thought to be due to the brain trying to stay awake and alert.

Does little sleep affect cognitive function?

We know that sleep is essential to adequate cognitive functioning throughout the day. Recent research has shown that giving up 1,3 hours of sleep a day causes a 32% reduction in alertness after one week with repercussions on physical and cognitive activities.

Memory and learning

Memory and learning are related to sleeping well. During sleep, the information acquired during the day is consolidated. Resting well is therefore essential to learning.

Different aspects of memory correspond to the different phases of sleep. For instance, the coding and consolidation of new information in our memory depends on the REM and Non-REM2 sleep phase. Failing to complete these stages, therefore, hinders the consolidation of memories. You can see its effects on academic performance.

There is also a relationship between sleeping and acquiring new information. In this case, little sleep decreases the activity of the hippocampus, the basic structure in the activity of memory coding, and hinders the ability to retain data.

Please note:

Another consequence of poor sleep is daytime sleepiness with effects on attention. In this case, since functions such as supervision are affected, we will have a tendency to lose or omit important elements in the performance of an activity.

It also becomes difficult to stay focused on the same activity for a long time. Add to this an increase in reaction time, it's no wonder that chronic lack of sleep can lead us to have a car accident or fail a test due to lack of time.

Reaction times

As we said, when we have late hours of sleep, our reaction times increase significantly. You are also more likely to make mistakes. In general, it will take us longer to complete an activity and even then we may have difficulty doing it correctly.

All of this affects every aspect of life. In particular, adolescents and young people who sleep little can have a decline in school performance, not being fully able to understand or perform what is required of them. Other impaired activities are automatic ones such as driving a car, due to slowing of reflexes.

What about the emotional life?

It seems that sleep deprivation causes temporary mood swings with a tendency to depression or anxiety. 

Likewise, it affects emotional intelligence and constructive thinking. The consequences are noted at various levels, first of all, interpersonal relationships. Getting little sleep reduces assertiveness, the feeling of independence and self-realization.

Secondly, empathy towards others and the quality of relationships are undermined. In particular, a decrease in the ability to recognize facial expressions related to joy and anger was noted. This certainly has consequences on the ability to relate to others.

Finally, the ability to manage stress suffers from, among other things, a delay in activating the gratification system.

Relationship between little sleep and physiological functions

Sleep is closely linked to physiological activities since, as we have said, it regulates our cognitive, emotional and physical life. Among the main systems affected by the lack of sleep we find:

  • Immune system. A reduction in sleep weakens our defenses and puts stress on the organs; increases the risk of getting sick.
  • Cardiovascular system. Those who suffer from sleep disorders are more likely to suffer from diseases such as hypertension, heart disease or heart failure.
  • Endocrine system. Sleeping little leads to an increase in cortisol levels and a decrease in thyroid hormones. For this reason there is a higher risk of suffering from obesity, diabetes and chronic fatigue.

Insufficient sleep syndrome

It is a disorder caused by a poor quantity and quality of night sleep, which is necessary for good vigilance during the day. Its origin is not physiological, but is linked to external factors. In particular, it is linked to a voluntary restriction of sleep motivated by other competing interests, such as fun or work.

It is typical of adolescents or young people of school age; the symptoms are daytime sleepiness, tiredness upon waking, the need for external help (mom and dad) to not get up late in the morning. Among the factors related to this syndrome:

  • Teenage changes.
  • Use of electronic devices.
  • Extreme hours and excessive school load.
  • Use of stimulants.
  • Emotional or stress factors.


We must never underestimate the physiological need to sleep the right number of hours. As we have seen, non-restorative sleep has negative consequences on the emotional, cognitive and physical level, therefore on our performance.

Do you have a habit of postponing bedtime because you have important things to do? Given the risks associated with getting little sleep, it is better to prioritize bed over other activities. In the long run, your body will thank you.

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