Insomnia is defined as the objective feeling of not benefit from sleep.
Sleep is a state opposed to waking due to the activation of specific nerve centers in the brain stem. A person in this state spends about a third of his life.
Sleep is divided into two main phases:
- slow sleep (or deep), the occurrence of a gradual slowing of brain activity;
- REM (Rapid Eyes Movement), in which dreams occur.
These two phases alternate from 4 to 6 times during the night.
Why sleep is so important?
The effects of deprivation hypnic have been the subject of numerous clinical studies, which have led to the conclusion that the lack of sleep is closely related to mental imbalance.
Among the most frequent effects that insomnia leads to find the difficulty of concentration, attention loss, aggressiveness and irritability, memory lapses and, in extreme cases, psychosis.
An adult needs an average of 8 hours of sleep a day; although to some people it takes less, without causing consequences. In these cases we speak of "healthy insomnia."
Insomnia is part of dyssomnia, a type of sleep disturbance due to the alteration of the quality of rest and is generally classified by taking into account at least three parameters.
1) The duration
Depending on the time frame in which one experiences, insomnia can be classified into:
Occasional: from one to three nights. It is often associated with periods of emotional tension as work or family problems.
Transient: three nights in three weeks.
Chronic: lasting more than three weeks.
2) The causes
Primary insomnia is not related to other physical conditions. The subjects are the so-called "bad dormitories", which have a normal sleep from the point of view of the duration, but altered as regards the quality, with the difficulties slowing of brain function during sleep "slow" and vital values ??higher than the norm.
secondary insomnia: linked to other conditions that cause the appearance. Among others: working shifts, psychiatric illness, abuse of stimulant drugs, pregnancy, brain injury.
3) The type
initial insomnia: the individual trouble getting to sleep, resulting in irritation and discomfort.
Central insomnia: characterized by frequent awakenings during the night.
Terminal insomnia: waking early, typical of the elderly over 65 years.
On a physiological level, the sleep-wake cycle is regulated by a fundamental substance melatonin.
Isolated for the first time in the University of Yale by the dermatologist Aaron Lerner, melatonin is a hormone that is produced spontaneously dall'epifisi, a gland located at the base of the brain. It defined an intelligent substance "" as it adjusts its production on the basis of external factors, namely light and dark.
During the day, melatonin levels remain relatively low, to rise gradually towards the evening, reaching the highest level at around 4 in the morning; melatonin in fact follows a true circadian rhythm. As we age the melatonin production decreases, due to calcification of the epiphysis: what causes insomnia increases resulting phase shift of the sleep-wake cycle.