For me 12 am - 1 am is the best time in a day. It's extra quiet, so peaceful and is the best time to do anything (except sunbathing). I usually do and/or practice my hobby (3d modelling) and get twice as focused as I usually do during the day. But, I have to always wake up at 5 am in the morning every day. So... am I always sleep for only 4 to 3 hours a day? No. 

Thankfully, I feel the opposite during the afternoon so usually I decide to take a nap and sleep like a dead body whenever I can. I mean literally, there's one time there was a small earthquake in my city around the afternoon and I didn't wake up. My parents called me a couple of times and I didn't answer (they were at my relative's house) so they went home faster than the Flash, only to find me just woken up and confused what are they so worked up about. 

So you could say my sleeping pattern is not healthy. 4 hours at night and a random amount of time in the afternoon, which is not every day. Not to mention sleep deeply during an earthquake, that's definitely unhealthy. 

The strange thing is, it's really hard for me to wake up even though my phone rings so loudly next to my sleeping face, or someone banging on my door. But, if someone call my name even if not loudly, I always wake up almost instantly.