Misconceptions about many aspects of sleep, including its duration are highly prevalent in the community. Sleeping for lesser duration is equated with evidence of hard work. There is no fact in this. An adolescent aged 14 or 15 years has to sleep at least 9 hours a day according to most experts. But will any child who is to appear for CBSE / SSLC be permitted to sleep this much ?
In reality, there is wide variation in the sleep requirement of individuals. Some can function without any problem even by sleeping for 4 or 5 hours. But generalizing this to the whole population will only lead to unnecessary conflicts. Advancing age reduces the need for sleep as well as results in fragmented and poor quality sleep.
Among the stages of sleep about 25% of time is spent in REM sleep and 75% in Non REM sleep. About 25 to 30% of the Non REM sleep is spent in superficial stages I and II. Usually this portion of sleep can be dispensed off without much adverse consequences. This is what is done by most short sleepers. They enter in to the deeper stages of Non REM III and IV within few minutes of sleep onset. The minimum time of sleep needed may vary from 4.5 to 5.5 hours. This is roughly the time spent in Non REM Stages III, IV and REM together. Reducing the time spent in these stages can lead to sleepiness, poor concentration, impaired work performance, accident proneness etc. If such a deprivation is prolonged mental or physical disorders can occur.
Dreams mostly occur during REM sleep. Dreams may occur in SWS also, but these are less likely to be remembered. It is usual for the sleep to be disturbed by dreams after being deprived of proper sleep the previous night. This is due to rebound of REM sleep. The body tries to compensate for the lost REM sleep by more frequent bursts in the succeeding night.
Dreams were thought to have symbolic meaning. This idea attained maximum scientific attention after Sigmund Freud's book 'The interpretation of dreams'. But now, neuroscientists and psychologists do not give much importance to the content of dreams in understanding the mental life of a person.
ഇന്ത്യ
6 months ago
2 comments:
Dear Dr.Harish,
Please explain Delayed Sleep Phase Syndrome.
Why do some persons still feel tired even after 9 or 10 hours sleep?
What are the non pharmacological and pharmacological management of these problems?
What is the risk reward ratio of pharmacological management?
Will insomnia cause depression?
Yes, Sashi. Unfortunately there is significant difference between natural sleep and that induced by hypnotic drugs. The aim of researchers in this area has been to develop a drug that leads to natural sleep. But the available drugs either suppress a tyoe of sleep or prolong another type, (REM versus Non REM) resulting in some difficulties.
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