Sleep is not an interruption of activity, it is another form of activity related to our brain.

Sleep is a normal physiological and periodic state characterized by vigilance suspension, loss of muscle tone, decrease heart rate and breathing and maybe the most important characteristic; we dream.

An all night sleep is very well organised and structured.

1. Light sleep (Stage 1 & 2).
2. Deep sleep or slow wave sleep (Stage 3 & 4).
3. Rapid eye mouvement sleep or REM sleep (Dream).
4. Cycles of 1h30 to 2 hrs.

Hypnogram

An hypnogram is a graph relating your sleep through an all night of recording. As you can see , there are  sleep stages and cycles.

When we say that the best sleep is in the fisrt part of the night, that’s because of the longer deep sleep period. This is the physic recovery !

We have more dream in the morning just before awakening. These are the dreams that we remember mostly.  Dreams are related to memory, cognitiion and intelligence.

But any kind of sleep is good ! These cycles last 1h30 to 2 hrs and we have 4 to 5 cycles by night !

Deep sleep or Slow wave sleep (SWS) is longer in the first part of the night and the dream period is shorter. But in the last part of the night (the morning) it is REM sleep (dream period) that becomes dominant.