The importance of sleeping and dreaming

The importance of sleeping and dreaming

If the dream did not serve an absolutely vital function, it would be the biggest mistake ever made by evolution. Allan Rechtschaffen

As human beings we have many needs: hunger, contact, sex, thirst and the act of sleeping.

Sound, sleep, dream, hallucinate, sleep, hallucination, lucid dreaming, nightmares, sleep paralysis, night terrorsThey seem to be terms taken from the trunk of the fantasy of the intangible, of the accessory: sometimes loaded with beautiful and sometimes very ugly events. However, in the crucible of these behaviors all are related to sleep and at the same time each of them are different.


  • 1 What is the dream?
  • 2 What is the circadian rhythm
  • 3 Our internal biological clock
  • 4 The importance of sleeping and dreaming
  • 5 Parasomnias
  • 6 Sleep or dream, is it the same?
  • 7 Strategies to measure sleep
  • 8 Stages of sleep
  • 9 Consequences of not sleeping
  • 10 Consequences of not sleeping well
  • 11 Precautions to sleep well
  • 12 Benefits of Healthy Sleep

What is the dream?

The dream is far from being a uniform state in which we enter shortly after retiring to rest and from which we leave upon waking. Sleep is a multifaceted, schematic and complex activity. We all know from our own experience that sleep varies from a mild state of sleepiness, from which it is easy to wake up, to the state of sleeping as a trunk, from which it is difficult to wake up (Santiago, Crider, Goethals, Kavanauugh and Solomon, 1989).

No wonder the confusion between sleeping (resting) and Sound (repair or recover), which for the common people is the same. And, most likely, that's where those two great trends come from explaining the way to sleep or dream through two great theories. One oriented to the behavior that we have during the day and night cycle and another one more as a homeostatic equilibrium process: molecular (chemical and electrical) and hormonal.

  • The essential of sleep recovery theories is that being awake alters, in some way, homeostasis (the internal physiological balance) of the organism, and it is necessary to sleep to restore it. So, Drowsiness is triggered by a deviation from homeostasis caused by wakefulness and that the dream ends when homeostasis has recovered.
  • On the other side, the circadian sleep theories they point out that this is not a reaction to the disturbing effect of being awake, but the result of an internal synchronization mechanism - that is, we beings humans we are programmed to sleep at night regardless of what happens to us in the day-. According to this, we have evolved to sleep at night because sleep protects us from accidents and predators (Pinel, 2007).

What is the circadian rhythm

The term circadian comes from the Latin circa, "around", and ten "day" Circadian rhythms, such as the sleep-wake cycle, have a periodicity of approximately 24 hours, that is, one day.

Many species of animals have been identified with an internal clock that govern every day of their lives. This watch has been perfected by many years of evolution and is our guide or our inner light. So listening to the body is a great way to get in touch with that watch to keep us healthier. If we act against it, we will surely suffer its consequences.

This main biological clock is located bilaterally in the suprachiasmatic nucleus of the hypothalamus anterior and obviously has reciprocal projections with the neural centers that regulate sleep and wakefulness.

Our internal biological clock

Chronobiologists are researchers who specialize in the study of internal clocks. Although we all have an internal clock, it doesn't work the same for everyone. Some have a cycle that works in 22 hours, while in others it works in one of 25 hours. We call people with these extremes larks and owls.

Larks are those that get up early with shorter biological clocks.

Those with a longer biological clock tend to lag behind and their behavior resembles that of the owl (Redolar, 2015; BBC, 2011).

This is why there are people who feel more comfortable doing their activities earlier (larks) or who like to work more at night (owls). The internal biological clock is also affected by our age. When we are babies and children we go to bed early, teenagers with a physiologically more altered biological clock go to bed late and wake up late, but when we reach fifty we go to bed like when we were ten years old.

Different theories lead to different interpretations, leading to controversies and polarizations. However, taking into account that knowledge is power, let's see an approach to the benefits of sleeping and dreaming in the short and long term.

The importance of sleeping and dreaming

The criteria that an investigator takes to choose an analysis topic are very varied and one of those routes is defined by the time invested in carrying out an activity, if this is little or a lot.

It is assumed that you cannot remember what happens while you sleep, most people tend to consider the dream as a state of consciousness, rather than as a behavior (Redolar, 2015). However, this does not happen. when we analyze lucid dreams, where the sleeper can have control of the scenes and actions taken during the dream, still in that dream state.

Let's go to extremes! Suppose that sleeping a lot brings health benefits: Why not spend life sleeping? And, suppose that little sleep helps us to do more activities during waking time: Why not sleep too little? There are also those who sleep too much, even if they want to avoid it and there are those who sleep less and would like to sleep more.

Having an internal biological clock makes us sleep on average for a certain time, but also among human beings, not counting sleep disorders, we need an average time to do so.

In the world of mammals there are those who sleep little and who sleep a lot comparatively with respect to the human being in one day: The giant lazy bear (20 hours), the giant armadillo (18 hours), the cat (14 hours), the jaguar (10 hours), the chimpanzee (9 hours), the human being, the rabbit and the pig (8 hours), the cow, the goat, the elephant, the donkey and the sheep (3 hours) and the deer and the horse (2 hours) (Pinel, 2007).

We spend a third of our life sleeping and of that third 20% dreaming. And yet, we hardly know anything about dreams. We have really wasted a lot of time interpreting dreams. Now neuroscience is discovering two fundamental things of dreams:

1) that serve to reorder memories, memories accumulated during the day and

2) the most important are a kind of healthy hallucination that serves to study the brain (Punset, 2015).

That is, a person of 60 years, will have slept 18 years of his life and more than 3 years dreaming.

Sleep is not a simple and biased behavior, it has a multiple function and holistic for the proper functioning of the human being. If someone did not sleep, he would end up dying.

It influences the activity of different areas, as mentioned by Stickgold (2015), director of the Sleep and Cognition Center of the Beth Diaconist Medical Center of Israel in Boston, all interconnected:

  • Biological and Physiological: maintains the balance of the immune system, and also in the elimination of toxins from the brain,
  • Endocrine: regulating the correct hormonal balance,
  • Psychological: maintain mental and emotional health,
  • Cognitive: contributing to learning and memory.

However, when we talk about the dream, it is not all the time as the stories or happy endings of the night say, they are sweet dreams. There are more than 100 sleep-related alterations and some of them are mentioned below.


Parasomnias are alterations or behavioral disorders related to sleep. They are brief or episodic. They usually occur in transitions between sleep and wakefulness, or vice versa, or in certain phases of sleep.

The International classification of sleep disorders (International Classification of Sleep Disorders or ICSD) distinguishes three large groups of sleep diseases: dysomnias, parasomnias (pathological disorders that occur during sleep) and psychiatric sleep disorders.

Some of the most common parasomnias

Dysomnias (lack or excess of sleep or poor quality sleep)

  • Intrinsic sleep disorders: Psychophysiological insomnia, Narcolepsy

Sleep apnea syndrome, Restless legs syndrome.

  • Extrinsic sleep disorders: environmental sleep, nighttime food or drink intake syndrome, sleep disorders secondary to alcohol, drug or drug intake.
  • Circadian sleep rhythm disorders: Syndrome of rapid change of time zone, sleep disorder of the night worker.

Parasomnias (partial interruptions of the brief and episodic type of sleep)

  • Awakening disorders: Somnambulism and night terrors.
  • Sleep-wake transition disorders: Nighttime speech disorders and night leg cramps.
  • Parasomnias associated with REM sleep: Nightmares, sleep paralysis, erections related to sleep disorders

Sleep disorders associated with medical or psychiatric processes

  • Depression
  • Parkinson's disease
  • Deadly Family Insomnia
  • Sleep related asthma
  • Gastric reflux related to sleep (Wikipedia, 2015).

And, is that sleeping and dreaming is not the same, but they are part of the same process of cell repair and balance in the homeostasis of body and mind. Or as we have already seen, they are part of the cycles of day and night.

Is sleeping or dreaming the same?

First, let's see that these are two different behaviors that are structurally and functionally conceptual, but that are part of the same behavior and sometimes they are talked about as if it were the same thing.

  • Sleep: Being, entering or bringing into the periodic state of rest, during which the senses and voluntary movements are suspended or inactive (Larousse, 2003). Sleep It implies being in a state of rest in which any conscious activity and any voluntary movement is totally suspended (DefinitionABC, 2017).
  • Sound: Perceive or imagine things that seem real while sleeping. Represent in the mind as possible or certain things that are not. Desire a thing with vehemence. Crave or crave Being a distracted person or expecting unlikely or difficult things is always in the clouds, daydreaming (TheFreeDictionary, 2017).
  • Dream: Mental state that occurs when you sleep and is characterized by a display of sensory, motor, emotional and cognitive experiences. Dreams occur more often, but not exclusively, during periods of MOR sleep (APA, 2010).

It is interesting to review how these two concepts come to be taken as synonyms both in everyday life and in some more specialized sources. If sleeping behavior is mentioned, the benefits or harms of not achieving deep sleep are immediately discussed and the reader must understand that it is the same. If not, you sleep well, you will have: benefits and harms !. It is difficult to differentiate both steps of this complex behavior, which we are fortunately getting to know more and more.

The act of sleeping is assigned an unconscious polysemic cultural function and has many implications and associations:

  • With death: "She fell asleep and no longer woke up," My pet was so sick that I preferred the vet to sleep it, "
  • With the absence: "Rita did not sleep at home"
  • With married or couple life: "Rubén has been sleeping with Lilia for a year",
  • With responsibility and forgetfulness: Victor fell asleep and passed his date to sign up for ...,
  • With accidents: "The accident yesterday was because the driver fell asleep at the wheel",
  • With boredom: "The class was so boring that I was sleeping",
  • With the effects of anesthesia in medicine: "In the operation they slept from the waist down,"
  • With the consequences of accidents: "Now his left hand is asleep",
  • With circadian habits: "It is impossible for you to sleep early,"
  • With the operation of our biological clock: "You sleep early and get up early, it's a lark according to your biological clock",
  • With the disease: "He is depressed and he is sleeping",
  • With stress chronic: “He has so much work that he hardly sleeps,”
  • With exaggerated confidence and foresight of the future: "He fell asleep on his laurels and that's why he lost the competition."

The list continues, and we are unable to distinguish that they are different and in turn complementary phases. Then, sleeping, goes beyond just resting and entering a period of voluntary inactivity of movement.

Sleep is a basic need of human beings and many other living beings. And, scientists divide it into phases, each with manifestations of brain activity, related to specific areas of the brain, as well as electrical, molecular and hormonal activity. Then, we will understand that sleep implies dreaming and dreaming is divided into complex and dynamic stages.

In the same way when we talk about dreaming, in the cultural and colloquial part we have this same polysemic function, but it denotes more specific and subjective elements, typical of each dreamer, not only in the field of their environment, but also of their personality and your state of physical and mental health. Relates to:

  • The imagination: You wake up and make castles in the air
  • Sleep disorders: Nightmares, insomnia, night terrors or sleepwalking. This job is a nightmare.
  • The production of oxytocin after having sex, in men and women, it makes them fall asleep because it produces them postcoital narcolepsy.
  • Seeing the future in the equivalent of having lucid dreams. "Things turned out just as I dreamed them."
  • The phases of sleep: I am a very light sleeper, I fell asleep and when the alarm went off I was dreaming that I was in a forest.
  • I couldn't wake up, I heard everything around and I felt that the dead man climbed, is the parasomnia called sleep paralysis.

The strategies to measure sleep

The sleep laboratories, using the combination of certain electrophysiological techniques jointly called polysomnography (PSG), have been able to observe that while one is sleeping there is a large number of physiological changes that define very different behavioral states. PSG consists of the simultaneous registration of several techniques ...

  • Electroencephalogram (EEG): using electrodes located on the scalp in central and occipital areas.
  • Electromyogram (EMG): using electrodes located on the chin to detect muscle activity.
  • Electrooculogram (EOG): through electrodes located on the outer edge of the eyes that register eye movements.

In addition, electrodes and transducers can be used to record heart rate, respiration, blood oxygen saturation, penile tumescence, or limb movements. The graphic representation of sleep in a human being is called a hypnogram. In it you can see the structure of sleep: the duration of sleep and the number of waking or waking episodes during the night (Redolar, 2015).

Sleep stages

The dream It is a singular behavior in which there are basically two different states:

  • REM sleep (Rapid Eye Movement, REM), it is a very active dream where the eyes move very quickly under the eyelids, this is when we dream and have nightmares and
  • The non-REM dreamIt is when the brain is calmer, the muscles relax, we secrete more hormones, the brain waves are getting slower and the heart beats more slowly. It is the moment when the body repairs itself, too. It is a deep sleep and there may be snoring, sleepwalking, soliloquies (talking alone). (Punset, 2014).

Both sleep states are very different from each other and at the same time from the waking state. And, they alternate during a night. Each cycle lasts approximately 90 minutes and includes a REM sleep of about 20 to 30 minutes. Therefore, in an 8-hour sleep, approximately four or five periods of REM sleep will occur.

Researchers have identified four different stages in sleep, each with its specific characteristics. Each of them seems to follow a continuum of sleep depth:

  • Stage 1: the lightest level of sleep, it takes place as soon as we begin to fall asleep. The EEG shows irregular waves of a relatively low voltage. It is characterized by the appearance of theta activity (3.5 to 7.5 HZ), which indicates that the discharge of neurons from the cerebral cortex is increasingly synchronized.
  • Stage 2: a deeper level of sleep, is identified by the appearance of very fast waves from time to time. These sudden occurrences of fast waves are known as sleep spindles, because they remember the thread wrapped around a sewing spindle.
  • Stage 3: mark a transition from a relatively light dream to very deep sleep. The EEG begins to show periods with very high voltage slow waves. These are known as delta waves.
  • Stage 4: it is the deepest level of sleep. Delta waves appear almost constantly in the EEG. Phases 3 and 4 in humans are usually grouped and jointly called slow wave sleep (SOL) (Santiago, Crider, Goethals, Kavanauugh and Solomon, 1989; Redolar, 2015).

If we manage to reach stage 4, we can say that we reach an optimal level and 100% reparative. However, when this is not achieved there can be from slight consequences, to extreme ones such as death.

Consequences of not sleeping

If a person suffers from insomnia (from sleep deprivation or from fatal family insomnia disease or death from human prion disease) for months he will end up dying.

Consequences of not sleeping well

  • Just one night of complete or partial insomnia alters different bodily functions, such as hormonal activity and protection against infections.
  • Insomnia favors weight gain. Increases ghrelin levels (appetite stimulating hormone). And, a tendency to suffer from obesity.
  • There is a relationship between sleep restriction and type 2 diabetes and the body's sensitivity to insulin decreases.
  • Apnea can cause snoring, gasping and other breathing disorders.
  • If you do not sleep well, we end up remembering much more negative events than positive ones, generating a biased and depressing memory of everyday life.
  • Not sleeping well negatively affects the functions of the central nervous system, impacting on memory, emotions and appetite regulation.
  • And, it also causes in some circumstances a major depression and contributes to other psychiatric disorders.
  • Little sleep is a wrong strategy to meet the demands of everyday life.
  • Who does not get enough sleep, runs the risk of ending - apart from very tired - sick, obese, forgetful and deeply depressed (Stickgold, 2015).

Precautions to sleep well

  • Exposure to sunlight during the day.
  • Do physical activity of aerobic preference.
  • Do not dine too much and avoid energy drinks, with a lot of sugar or even alcoholic drinks.
  • Avoid drinking three hours before going to sleep.
  • Have a fixed routine to sleep at least 7 hours a day.
  • Elsa Punset proposes to sleep well: Set a bedtime schedule and another to get up, do vigorous aerobic exercise (walking, running, dancing, etc.) no matter the time, take a hot shower before bedtime and leave worries for tomorrow ( Punset, 2014).

Benefits of healthy sleep

  • Have a radiant complexion.
  • Our immune system is strengthened.
  • It is possible to lose weight if you are well rested.
  • If you slept well you will wake up more optimistic and happy (DefinitionABC, 2017).
  • Cure drowsiness.
  • It influences the optimal functioning of numerous biological processes.
  • It improves the performance of the immune system, the correct hormonal balance, mental and emotional health, learning and memory, and also in the elimination of toxins from the brain. While the physiological mechanism by which sleep influences mental health is unknown, it is suspected that it has a lot to do with transforming daily experiences into memories. Thus, it has been proven that sleeping after learning activities facilitates stabilization, consolidation, integration and selective analysis of new memories. The dream thus controls what we remember and how we remember it. The dream reinforces all those elements that he considers valuable. Reinforced memory in the dream serves to strengthen the future, not the past (Stickgold, 2015).
  • In this way the colloquial affirmation of consulting things with the pillow before making an important decision in life is true.


APA (2010) Concise Dictionary of Psychology, Editorial El Manual Moderno, México.

BBC (2011). The human body clock, accessed May 31, 2017, online: //

DefinitionABC (2107) Definition of sleep, accessed May 29, 2017, Online: //

Pinel J. (2007). Biopsychology, Pearson Addison Wesley Publishing House, Madrid.

Punset E. (2014) Tips for a good night's sleep, accessed May 31, 2017, online: //

Punset E. (2015) Networks, nightmares are not dreams, consulate on May 28, 2017, online: //

Redolar D. (2015). Cognitive Neuroscience, Editorial Panamericana Médica, Madrid

Santiago Z., Crider A., ​​Goethals G., Kavanaugh R. and Solomon P. (1989). Psychology, Editorial Scott, Foresman and Company, Glenview, Illinois.

Stickgold R. (2015) Benefits of sleep (How it influences the nervous, immune and endocrine systems), The vital functions of sleep, Journal Research and Science, Number 471, Barcelona.

TheFreeDictionary (2017) Definition of Dreaming, accessed May 31, 2017, online: //

Wikipedia (2015) International Classification of Sleep Disorders, accessed May 27, 2017, online: //

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