| You are right (and very observant) that this is mostly Ekrich when you dig into it. I didn't realise this until quite recently, and I too had assumed there was a lot more work about this. But what he's found in literature is pretty consistent, and biphasic sleep was once quite normal in a specific context: the siesta. It's dying out in continental Europe alas -- a lost cultural touchstone -- and in the contemporary West, a siesta is short (literally a nap). But a traditional Spanish siesta is the best part of a sleep cycle -- a good couple of hours, with an hour's rest spread either side. More than enough that you could have four hours sleep overnight throughout the longer days and not be incompetent the next day. My sleep is currently polyphasic, which is not a great time. But it has taught me that sleep in the absence of natural light (or the presence of consistent artificial light) does have a habit of going polyphasic. I woke up at 4:15am after about five hours of sleep. I just cleaned a grill pan. I may go back to sleep again. Sleep scientists seem pretty sure that polyphasic sleep is bad. |