Sleep is an activity necessary for the survival of our organism . The exact causes of why we need sleep are still unknown, but it appears that it primarily serves the function of letting our brains and bodies “rest” from daily activity. You cannot live long without sleep , more than three days without falling asleep at all can have disastrous consequences.
How much do we need to sleep?
We don’t all need to sleep the same number of hours . Generally, younger people, those who make intense physical or mental efforts, as well as certain personal characteristics, usually need more sleep. A child may need to sleep about 10 hours a day, an adult between 6 and 8 hours, while an elderly person may have enough with 5 or 6.
It is very important that the sleep is of quality and without fragmentation. Five hours of deep and restful sleep can rest more than eight hours suffering from nightmares or discomfort . But the dream is not only a mere rest, but also serves to discharge a good number of tensions originated during wakefulness, and this is where our ability to dream plays the most important role.
Sleeping and dreaming are two closely linked processes , although they are not always accompanied. We do not dream all the time we are asleep, but only during certain specific periods called MOR (rapid eye movement) or REM (rapid eyes movements) phases in English.
When we go to sleep , in the first place a state of numbness or dream occurs, whose duration is usually half an hour and during which the waking state is passed to that of sleep with a progressive decrease in consciousness. Throughout this phase it is normal for visual or auditory illusions to be produced (there is the illusion of hearing or seeing things that do not exist), as well as cramps, dizziness or stumbling sensation.
Later, when we are already in deep sleep, the REM sleep phases follow one another with those of non-REM or superficial sleep . The first REM phase usually occurs between the first and second hour of sleep, then appears intermittently throughout the normal sleep period. This phase is also called the paradoxical sleep phase, since if we perform an electroencephalographic (EEG) trace we would see that it is very similar to when the person is awake, it is also the phase in which it is most difficult for the person to wake up.
It is in this phase that most of the dream activity occurs. Also in this phase a series of changes occur such as:
- Decreased muscle tone.
- Increased electrical resistance of the skin.
- Pulse and breathing disturbances, which become more irregular.
- Slightly increases motility of the digestive system
- Erections occur in men.
- Increased vaginal blood flow in women.
Much of these modifications are due to activation of the hypothalamus and pituitary , which increase the secretion of certain hormones such as testosterone, cortisol or growth hormone.
What happens when we dream?
There is no uniform opinion today about the significance of dreams. Already in antiquity it was believed that dreams were in relation to the world of the superhuman , and that they brought with them divine revelations, especially about the future of the individual. Even Aristotle believed in the possibility of finding in dreams the indication of the beginning of some disease of which we still cannot be aware during wakefulness due to lack of symptoms.
Sigmund Freud , in his famous play The Interpretation of Dreams wrote that dreams were the fulfillment of our deepest desires, which we could not carry out while awake. According to him, dreams would be the expression of an unsatisfied desire. He basically attributed a sexual type character to them. Later Freud himself recognized that this was not always the case, and that they could also be the manifestation of a problem or a concern, even the expression of fears of the unconscious, as occurs with nightmares or anxious dreams.
It can be said that to a greater or lesser degree the content of dreams is determined by the personality of the individual , his life and his past experiences. Thus, the most frequent content of dreams is constituted by the daily events lived by the person, but distorted by the subconscious. In fact, it has been verified that the content of dreams is often related to the activity carried out during the same day and, especially, to the images perceived during the moments immediately before falling asleep.
It can also be seen that many dreams contain memories of childhood and youth, sometimes bringing back old memories that we thought were lost. This is a relatively normal phenomenon, perhaps due to the great importance that these memories usually have for the person’s life, although it has not been demonstrated.
Types of sleep
Some dreams have been observed that many people have , such as believing that we fall from a height, dreaming that we fly, that we lose a tooth or feel ashamed because we think that we are naked or poorly dressed. The dream of falling from a height is almost always caused by the fact that, being already unconscious even of the sensation of contact and pressure on the bed, we move an arm or a leg in such a way that this movement becomes partly conscious but distorted and we think we are falling. The dream of losing teeth is also attributed to a momentary oral sensation and that of feeling naked is related to the fact that we had come out of the sheets that covered us.
In some people there are certain dreams that are repeated and that are generally full of anguish. Sometimes they can be the expression of psychological trauma that has not yet been assumed by the person.
Something curious in dreams is that we generally do not remember them, or only those that we had at the last moment before waking up, and even these are forgotten with extraordinary speed, except perhaps those that have had a great impact on us. This is because in this way we do not end up storing in our brain meaningless memories that could confuse us, because when we wake up we have to know how to distinguish reality from reverie, so the latter is erased from our memory as a security measure.
The dream ultimately manages to separate the individual from his awake life, as well as from daytime pressures . But it has not yet been possible to establish exactly what their definitive origins and functions are, nor has it been scientifically proven that premonitory dreams exist, until now everything is more or less certain hypotheses of our dream life.