Becoming an Early Riser / Polyphasic Sleep

[BSper]

I'd like to hear others experiences with these topics. My goal over the next few months is to get my sleep pattern in order, and possibly try polyphasic sleep. My sleep patterns are like Steve's used to be.. I get up at around 9 or 10 and find myself sleeping 8+ hours per night. I know that I should be able to run off less sleep than this. My problem is that when I get around 6-7 hours per night for more than 2-3 nights in a row (with no naps) I get sick. Any ideas on this? or what I can do to overcome this. I know if I want to start polyphasic sleep, I need to first master getting around 7 hours of sleep per night while staying healthy.