So if you're used to sleeping for eight hours at a time...should you set your alarm for four hours, wake up, do something sedate for a while, and then go back to bed? Should it be more like 4.5 so that (in theory) it happens at the end of a 1.5-hour sleep cycle?
I don't think you should set an alarm ever if you can help it.
If the theory is that bi-phasic sleep is ideal and natural for us, you should fall into that pattern naturally. All you need to do is go to sleep around the time that the sun goes down. It's just that "easy".
