Do you sleep all through the night? Do you need to? This very interesting article points to research indicating historically it was commonly accepted that two 4 hour periods of sleep interspersed with a two hour wake period was the norm. This seems to be the case for me. How about you?
[url=http://www.bbc.co.uk/news/magazine-16964783]BBC News - The myth of the eight-hour sleep[/url]