The conditions of complete isolation are able to eliminate the action of the environmental synchronizers, in these situations the internal oscillators tend to assume different rhythms from that of 24 hours (the free-running man tends to synchronize preferentially on the rhythm of 25 hours) and can desynchronize with each other (Lungaresi E., 2005; G. Coccagna., 2000).
Clinical syndromes determined by external factors are included, such as the rapid change of the time zone following transmeridian flights and rotating night shifts, and other syndromes that appear to have an endogenous component, such as that of the delayed (or advanced) sleep period. ) and that of a non-24-hour Sleep-wake rhythm.
In all these syndromes, regardless of the causes that determine them, a phase shift of the Sleep-wake rhythm occurs with respect to the usual environmental synchronizers, with the consequent appearance of a pathology concerning the moment in which Sleep and wakefulness appear. The patient is unable to sleep when he wants, needs or would expect to. It should also be noted that long-lasting insomnia or hypersomnia can cause profound alterations in the sleep-wake rhythm which are important factors in aggravating and maintaining symptoms (Sudhansu Chokroverty., 2000; Coccagna G .; Smirne S., 1993).
According to the classification of the AASM (Classification Committee., 1979), sleep-wake rhythm disorders are divided into: Transient disorders and persistent disorders.
Transient disturbances are:
- Rapid time zone change syndrome
- Shift shift syndrome
In general, the complaints subside considerably after a couple of days, but in some people they can last longer. Flights to the east involve longer disturbances. The restoration of the sleep-wake pattern, once back in the place of origin, is generally faster.
For further information: Jet lag: causes of the time zone syndrome and decrease in mental and motor performance during the new work-wake period, ie at night, as well as from Sleep, during the day, reduced and fragmented by numerous awakenings.This symptomatology appears more severe in elderly subjects who have been exposed to night shifts for a significant number of years.Symptoms may improve during the second or third week of work, but often persist, at least partially, especially in subjects who already start from a more difficult night sleep or in subjects whose chronotype (owl or lark) is more in counterphase than the rhythm imposed by the work shift.
During weekends and holidays, lost sleep and physiological rhythm are generally recovered with a rapid decrease in symptoms.
Next: Persistent sleep-wake rhythm disturbances
