Sleep Physiology : What happens when you Sleep.

Sleep Physiology : What happens when you Sleep.

There are five stages of sleepthat the human body goes through. A complete cycle takes an average of 9-10Minutes. The sleep cycle begins from stage 1 and ends in REM (RapidEye Movement). The first sleep cycles have short REM sleeps and longperiods of deep sleep.

But later during sleep, REM periods lengthenand deep sleep time decreases.

NON REM STAGES

Stage 1.

This is the period whenyou first fall asleep and you can be awakened easily. In this stagemuscle activity slows and the eyes move slowly. People often experiencesudden muscle contractions preceded by a sensationof falling from a height.

Stage 2.

In this stage eye movementstops and the brain waves become slower and there are bursts of rapid brainwaves.

Stage 3

In this stage brain wavescalled delta waves are mixed with smaller faster waves. Deep sleep beginsin this stage.

Stage 4

In this stage the brainproduces only delta waves. There is no eye movement or muscle activity.This is the stage where children may experience bed wetting, sleepwalkingor night terrors.

In the REM period, breathing becomesshallow, irregular and rapid. Muscles in the limb are temporarily paralyzed.Blood pressure rises, heart rate increases, males develop erectionsand thebody cannot totally regulate temperature. This is the period whendreams occur.

Humans experience 3-5 intervalsof REM sleep each night.

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