I had a biphasic schedule about 8 years ago for 9 months. I slept at night from 1:30am to 6:00am and in the afternoon from 3:00pm to 4:30pm. I was never tired.

I had a biphasic schedule about 8 years ago for 9 months. I slept at night from 1:30am to 6:00am and in the afternoon from 3:00pm to 4:30pm. I was never tired. I felt like I had two days in one. It was great. I worked from 7am - 2pm, ate lunch, and went back to sleep. When I woke up at 4:30pm, I had 9 hours of free time until I would sleep next. I don't have a flexible work schedule like that anymore, and now that I live in San Francisco, the environment is not exactly quiet enough at 3pm for quality sleep. I recommend trying it out if you have the flexibility. Avoid caffeine. Treat the afternoon sleep time, the same as you would the night time. Block out noise and light. Be consistent. Having two days in one is pretty awesome.