Sleep is an impor­tant part of any per­son­’s life. If a per­son can live with­out food for sev­er­al days, and some peo­ple even for weeks, then with­out sleep this fig­ure is much low­er. The longest peri­od of wake­ful­ness with­out a break for sleep was record­ed at around 19 days, but this is more of an excep­tion to the gen­er­al rule. An ordi­nary per­son, even after one sleep­less night, does not feel very well: con­cen­tra­tion of atten­tion decreas­es, the activ­i­ty of the ner­vous sys­tem slows down, severe fatigue, apa­thy, dizzi­ness and headaches both­er. If the next 2–3 nights dream for some rea­son it also does not occur, then var­i­ous seri­ous depres­sive dis­or­ders may occur, there is a risk of devel­op­ing hal­lu­ci­na­tions and night­mares.

Ideal sleep duration

Mod­ern med­ical sci­ence is of the opin­ion that opti­mal sleep dura­tion in an adult is 6.5–7.5 hours. If a per­son sleeps less than 5 hours a day, then this threat­ens his health, and there is evi­dence of a reduc­tion in life expectan­cy in this cat­e­go­ry of peo­ple. First of all, the ner­vous sys­tem and metab­o­lism suf­fer. How­ev­er, an exces­sive­ly long sleep is no less harm­ful to the body than a short one. In the group of peo­ple who spend more than 9.5 hours in bed, life expectan­cy was also low­er than in those who sleep less. It’s no secret that the Japan­ese are long-lived. Per­haps the rea­son for this is that one of the most impor­tant dai­ly rules for them is reg­u­lar sleep of about sev­en hours.

Sleep morphology

Imme­di­ate­ly before sleep there is a state of falling asleep or drowsi­ness, which is well known to every­one. It is man­i­fest­ed by yawn­ing, a decrease in the lev­el of con­scious­ness, a slow­ing of the pulse, a decrease in the activ­i­ty of the endocrine glands. If the envi­ron­ment is con­ducive, then the per­son then falls into a dream.

Dur­ing sleep, cer­tain parts of the brain are acti­vat­ed — somno­genic, while the rest of the parts are rest­ing. Dur­ing sleep, there are 2 phas­es:

1. Slow-wave sleep (ortho­dox, syn­chro­nized), which takes 70–80% of the total sleep time in dura­tion. In non-REM sleep, the fol­low­ing phas­es are dis­tin­guished:

Stage I — relaxed wake­ful­ness and drowsi­ness,

Stage II — super­fi­cial sleep,

Stage III — sleep of medi­um depth,

Stage IV — deep sleep.

Wak­ing up a per­son in stages I and II is quite easy, while in stages III and IV a per­son is very sound asleep.

2. REM sleep (desyn­chro­nized), tak­ing up 20–30% of the time, respec­tive­ly.

Dur­ing REM sleep, a per­son­’s eye­balls move and he sees dreams.

The fast and slow phas­es replace each oth­er, and for the whole night a per­son alter­nates 4–6 cycles. The first two cycles of non-REM sleep are the deep­est, and lat­er cycles are less deep, so the longer a per­son sleeps, the eas­i­er it is to wake him up.

surrealism, face, colors
fantasy, people, mysticism
fantasy, people, mysticism

Nor­mal dream pro­vides a per­son with good health, mood and is sim­ply nec­es­sary for the nor­mal func­tion­ing of all organs and sys­tems. In no case should you neglect 7–8 hours of sleep dai­ly for the sake of work, doing house­hold chores or watch­ing TV at night.

By Yraa

Leave a Reply