Sleep: what happens to your body when you sleep

Our sleep is divided into four phases that are repeated up to 5 times during the night, as explained by Professor Luigi Ferini Strambi, neurologist, director of the Sleep Medicine Center at the San Raffaele hospital in Milan

First phase: NREM (non rem)characterized by the relaxation of the muscles and lasts just 2-3 minutes. the phase of falling asleep and represents about 5% of the whole night
Second phase: lasts approximately 10-15 minutes , a phase of light sleep and preparing to enter deep sleep. Sleep spindles and K complexes alternate on the encephalogram tracing.
Third stage:Deep sleepsleep ad where lens: the activity of the encephalogram is very slow, the brain seems to be in “stand by” and goes into a condition of hypometabolism: cconsumes less energy. This phase lasts approximately 40-50 minutes with a few small breaks when it comes back to phase two.
Fourth stage: REM characterized by intense brain activity, the eyes move rapidly in different directions . The sleep lightensYes, at this stage dreambut at the same time some sort of appears paralysis of voluntary muscles(otherwise the dreams would actually take place, with consequent nocturnal movements), for this reason also called paradoxical sleep. The cerebral metabolism is sometimes more active than in the waking phase. The REM phase lasts a short time, about 4-5 minutes because then you return to phase two and deep sleep

The nonREM-REM cycle lasts approximately 90-100 minutes and repeats 4-5 times during the night. Deep sleep lasts longer in the first few cycles. The deeper you go into the night, the more deep sleep tends to decrease while REM sleep increases