For all the sleeping beauties...

Came across an interesting article "The myth of the Eight Hour Sleep" that indicates how the sleeping pattern might have evolved over the last few hundred years and that "a consolidated eight-hour sleep may be unnatural".

Stages of sleep

Every 60-100 minutes we go through a cycle of four stages of sleep

Stage 1 is a drowsy, relaxed state between being awake and sleeping - breathing slows, muscles relax, heart rate drops
Stage 2 is slightly deeper sleep - you may feel awake and this means that, on many nights, you may be asleep and not know it
Stage 3 and Stage 4, or Deep Sleep - it is very hard to wake up from Deep Sleep because this is when there is the lowest amount of activity in your body
After Deep Sleep, we go back to Stage 2 for a few minutes, and then enter Dream Sleep - also called REM (rapid eye movement) sleep - which, as its name suggests, is when you dream
In a full sleep cycle, a person goes through all the stages of sleep from one to four, then back down through stages three and two, before entering dream sleep
Source: Gregg Jacobs

To read the complete article: http://www.bbc.co.uk/news/magazine-16964783