Our Nights Are More Disturbed Than We Realise

The stages of sleep repeat themselves through the night in roughly 90-minute cycles.
Typically, the sleeper spends 55-60 per cent of total sleep time in light sleep, followed by 15-25 per cent in deep, or Delta sleep, and 20-25 per cent in Rapid Eye Movement sleep.
In REM, despite the constant flickering of the eyes, there is a complete relaxation of all the postural muscles of the body, while the brain shows identical activity to when it’s awake.
Our nights are more disturbed than we realise.
There might be more than half-a-dozen moments of awakening, but if these moments last for less than three minutes we have no memory of them.
Memory in sleep operates in a different way and a different place, as anyone who has struggled to remember a recent, vivid dream knows.
(David Flusfeder)