In detail

Our mysterious ally: the dream

Our mysterious ally: the dream

A third of our existence (220,000 hours in 60 years) we spend with our eyelids closed, in a mysterious and unknown state that we call dream. But beware! All this time is an active time and in it many changes occur both in mental activities and in bodily functions, and all of them of enormous importance for our physical and psychic balance. In short, it fulfills a restorative function for our body, it helps with energy recovery, thermoregulation, the consolidation of learning and memory, among many other functions.

It is important to mention that about the importance of dreams he already spoke to us Aristotle, and many historical figures have recorded their dreams: Julius Caesar, Discards, Bismarck, Hitler and many others, however, until 1899, when Sigmund Freud publish your work The interpretation of dreams, there is no real scientific or professional interest in its interpretation.


  • 1 Phases of sleep
  • 2 Quantity and quality
  • 3 sleep problems

Phases of sleep

In the sleep period we find two stages, called the slow sleep phase or NO REM, and fast sleep phase or REM (acronym that corresponds to its name in English:Rapid Eye Movements or rapid eye movements). The no REM sleep, in turn, is divided into four phases with different characteristics. These phases alternate cyclically while we remain asleep (every 90/100 minutes, approximately, begins a new sleep cycle in which the last 20 or 30 minutes correspond to the REM phase).

  • Phase I. It is the phase of light sleep, in which people are still able to perceive most stimuli (auditory and tactile). Phase I sleep is little or nothing restorative. Muscle tone decreases compared to the waking state, and slow eye movements appear.
  • Phase II In this phase the nervous system blocks the access routes of sensory information, which causes a disconnection from the environment and thus facilitates the activity of sleeping. Here the dream is partially restorative and occupies about 50% of the sleep time in the adult. Muscle tone is less than in phase I, and eye movements disappear.
  • Phase III It is a deeper sleep (called DELTA), where sensory blockage intensifies. If we wake up during this phase, we will feel confused and disoriented. In this phase you do not dream, there is a 10 to 30 percent decrease in blood pressure and respiratory rate, and growth hormone production is increased. Muscle tone is even smaller than in phase II, and there are also no eye movements.
  • Phase IV It is the deepest phase of sleep, in which brain activity is slower (predominance of delta activity). Like phase III, it is essential for the physical and, especially, psychic recovery of the organism (phase III and IV deficits cause daytime sleepiness). In this phase, muscle tone is greatly reduced. It is not the typical phase of dreams, but sometimes they can appear, in the form of images, lights, figures ... without a plot line.
  • REM phase: It is also calledparadoxical dream, due to the contrast of muscular atony (total relaxation) typical of deep sleep, and the activation of Central Nervous System (wakefulness and alertness). In this phase dreams are presented, in the form of narration, with a plot thread although it is absurd. The electrical brain activity of this phase is rapid. The null muscle tone (muscular atony or paralysis), prevents the sleeping person from materializing their dream hallucinations and can be harmed. The most typical alterations of this phase are nightmares, REM sleep without atony and sleep paralysis.

Quantity and quality

Regarding the ideal quantity, there is no very reliable standard measure because not everyone has the same needs. Some are great with five hours and others with ten, and both ends are normal. Young people, athletes, people who make great physical or psychological efforts, who have a larger constitution usually need more.

As a curious anecdote I tell you that Edison I used to sleep an average of five hours while Einstein I used to sleep ten hours. What matters in the end is quality rather than quantity.

What is certain is that if we stay awake for a very long period of time or if we try to suppress sleep continuously, alterations in our body will appear, for example: an increase in anxiety and irritability, problems with attention, concentration and memory, loss of reflexes, depression and in severe cases even death.

Sleep problems

As we have seen the fact of not getting a deep and deep sleep causes serious problems. We can all "lose sleep" promptly, this can be for several reasons, for example: situations that lead to stress, health problems and medications, too many hours of work / shift work, drinking alcohol, eating too close to bedtime , etc. However, most of these situations are punctual. When this is not the case, when the problem is very constant, we fall asleep during the day, snore or find ourselves emotionally unstable, then we have to take action, as they can be indicators of sleep disturbances. We will know only some of the most common:


We talk about insomnia when the problems of quality and / or quantity with sleep, exceed an intensity that makes them intolerable and when we have symptoms such as: mood disorders, difficulty concentrating, drowsiness with difficulty being able to sleep during the day, physical and mental fatigue, state general nervousness, tension and anxiety.

There are many factors involved in the appearance and maintenance of insomnia. Among the most important are the psychological ones (tendency to turn things around, difficulties in handling negative emotions, wrong beliefs in relation to sleep, and consequent inappropriate habits), stress and fear of not sleeping.

Both main types of insomnia are:

  • Primary insomnia: when the cause that causes it is not easily identified or is not associated with any other disease
  • Secondary insomnia: appears as a result of different causes, such as illness, mental disorder, the consumption of certain substances or medications or the existence of environmental (noise, temperature) or social problems (family and work problems, changes in work or travel schedules ).

Depending on the duration of insomnia we would also have: temporary insomnia (its duration is less than one week), short-term or acute insomnia (lasts one to four weeks) e chronic insomnia (lasts four weeks or more).


The hypersomnia it is a disorder of the sleep mechanism, which is characterized by a constant and involuntary excessive sleep. We would have great difficulty to stay awake, and this would cause us a significant functional deterioration, among which we would have: fatigue, fatigue, loss of concentration and sensory, movement problems and a great loss of attention in our environment.

In most cases they have no difficulty falling asleep; This is continuous, but not repairing. We usually have problems getting up feeling confused and irritable, presenting what is known as sleep binge and that affects during the sleep-wake transition.

During the day, there is an almost continuous feeling of drowsiness, in which automatic and routine behaviors can occur, of which we would not become aware.


The somnambulism it is a disorder that occurs when we walk or do another activity while still asleep. We can stand up and look as if we are awake, get up and walk or perform complex activities. Some people even drive a vehicle while they are asleep.

The episode can be very short (a few seconds or minutes) or it can last up to 30 minutes or more, but most episodes last less than 10 minutes. If they are not disturbed, the sleepwalkers will return to sleep. However, they may fall asleep in a different or even unusual place.

This disorder can occur at any age, but it occurs more frequently in children 5 to 12 years of age, and appears to be hereditary.

In adults, sleepwalking may occur due to: alcohol, sedatives or other medication, medical conditions such as partial and complex seizures or mental disorders.


It is the most serious case of hypersomnias, it is a sleep disorder that causes excessive sleepiness and uncontrollable and frequent sleep attacks during the day, Usually at inappropriate times these periods of extreme drowsiness occur every 3 or 4 hours, this impulse Sleep is uncontrollable and disabling.

More than half of individuals with narcolepsy may experience sudden muscle loss and weakness (cataplexy) triggered by a sudden emotion, as well as sleep paralysis, in which there is momentarily inability to move or speak upon waking.

About half of individuals with narcolepsy go through sleep-like states, between sleep and wakefulness (hypnagogic hallucinations). The narcolepsy It is caused by low concentrations of chemical messengers in the brain (dopamine Y norepinephrine), and by genetic factors. 

Do not miss: Phrases about dreams


  • The dream (2007). In Encyclopedia of Psychology (Vol. 4, 11-55 pp). Spain: Ocean.
  • Medline Plus (2013).Somnambulism. Date of consultation: October 5, 2015. Available at //
  • Ruíz de la Rosa, J. (2014). Dreams. Date of consultation: October 5, 2015. Available at //
  • The phases of sleep. (2015) Date of consultation: October 5, 2015. Available at: //