Is biphasic sleep polyphasic? I have been living this way since the time I entered the university, and this is already - no less - 5 years.
I came to the need to get some sleep during the day because night sleep did not cover my needs. At first there was a long night's sleep and a small siesta, but as the daytime sleep settled, the nighttime became shorter by itself, because after 3-4 hours of sleep after couples you hardly want to go to bed at 10.
I would change the regime, if you could? I think yes. Why can't I? Because I don’t know under what conditions I can get the required 10 hours of sleep at once. And if I have a siesta, 5 hours of nighttime and 4 hours of daytime sleep helps me to stay afloat, and so it even seems like I have more time.
Works. The harm has not been studied. But there is speculation that biphasic sleep allows you to be more productive. But I would not recommend a larger partition. Otherwise, you should stick to the standard monophasic mode. You can google articles about personal experience, here are a couple: https://habr.com/post/244007/ http://thevyshka.ru/15682-polifazny-son-experiment/
I have a strong sleep disorder since childhood, now phased sleep is practiced by itself - without an alarm clock I can fall asleep at 22 and wake up at 1 am, and I feel fine - I work until 10-11 am, and then sleep again. I think you need to look at your own well-being. If you can wake up yourself after a couple of hours of sleep, then this mode will suit you
Now this video is not on YouTube, but I watched the girl's experiment with this type of sleep for 2 months. She told me that you very quickly enter the regime and sleep literally everywhere, including cafes and shops in squares, that you really get enough sleep and you have a lot of time, but it is impossible to live in this regime for a long time.