I usually sleep at 4hr intervals, too. I'll go to sleep watching TV at about midnight and wake up at about 4am, when LDN has raised my endorphin level, back to sleep at 5 and up at 9am....so I get eight hrs of sleep and usually am refreshed in the morning.

I actually, like my sleep pattern now. It seems to work for me. Of course I also take a 2 to 3hr nap in the afternoon..