Here is what I found the most thorough yet concise resource on sleep. http://www.supermemo.com/articles/sleep.htm http://www.supermemo.com/articles/sleep.htm

Here is what I found the most thorough yet concise resource on sleep. http://www.supermemo.com/articles/sleep.htm http://www.supermemo.com/articles/sleep.htm You'll see that the sleep patterns can vary a lot, however it still holds true that the last phase is most important. I wouldn't pay much attention to slicing and dicing the sleep pattern but focus on what brain works on at a particular phase. With regards to day cycle - the article on supermemo shows two main types - one that needs to shut down in the midday and one that doesn't. It should be easy to find out which group you belong to.