Sleeping for 7 to 9 hours at night isn't the only way to catch some z's. Here are four alternative sleep cycles -- and ...

Biphasic sleep is a sleep schedule that involves two periods of sleep over 24 hours, which is often sleep at night plus a nap. Monophasic sleep is a schedule that involves one period of sleep, and ...

This is called biphasic sleeping and it may be much more common than you think. In the 8th-Century BC epic poem, the Odyssey, Homer refers to the ‘first sleep’, in what is one of the earliest ...