The problem most people face is not having enough time. When I was in graduate school I was also working full time so I started trying to figure out ways to sleep less so I could get more done. Up until that time I had always slept about 8 hours a day, but I started to wonder how much of that time could I cut off that 8 hours and still function properly.
I first started by just slowly going to bed 15 minutes later each night and forcing my self to wake up at the same time. This got me down to 7 hours pretty easy, but that's where I got stuck. Any less than 7 hours and I was like a zombie. So after some more research I started using sleep cycles to my advantage.
The body functions on an approximate 90 minute sleep cycle. This means you go through all the levels of sleep including the most important, REM sleep, in about 90 minutes. When you wake up in the middle of the night naturally you know you have just completed a sleep cycle. You can use the times you wake up naturally to go back and calculate your average sleep cycle time. For me a its about 80 minutes.
This is helpful because you can use this information about your own body clock to time going to bed so that you'll end a sleep cycle close to the time when you want to wake up. I was able to get down to 4-1/2 to 6 hours of sleep per night no problem doing this method. I actually felt more tired waking up mid-sleep cycle from 8 hours of sleep than waking up exactly at the end of a sleep cycle with 6 hours of sleep.
I've also converted to bi-phasic sleeping. I've found for me that sleeping once a day leaves my mental energy low in the evening. So now I sleep for about 3 hours in the evening and then 3 hours at night. I know this may seem a little weird to sleep twice a day, but most animals are polyphasic sleepers. I think monophasic sleeping is an unnatural habit that has become a cultural standard. Sleeping multiple times a day also cuts down on the number of hours you need to sleep to feel refreshed. People sleeping 3 hours twice a day will feel more refreshed than people sleeping 6 hours once a day.
Good night and good luck!
