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by leoc 2192 days ago
Isn't human sleep naturally biphasic rather than monophasic? https://www.sciencealert.com/humans-used-to-sleep-in-two-shi...
4 comments

More than that, hunter gatherers pretty much just sleep whenever they want. It's only since the shift towards pastoralism and then agriculture that necessitated a regular sleep/wake cycle.
I'd look at studies like [0], which indicate that the answer is "no". When given no indication of time, humans tend towards a ~24h sleep period.

[0]: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1330995/

I've thought for at least 15 years that my natural sleep pattern was 3AM->8AM with another "nap" from PM6->9PM. But this COV19 work from home thing, and my weekend sleeping patterns for a few years now, has been PM3-6PM.

So, whether this reflects some deep sleep dysfunction or what, I don't know. What I do know is that i'm a lot more productive/etc when I sleep when I feel tired.

Given how hot it gets in TX I don't really mind missing the 3-4 hours during the hottest part of the day.

If you count an early afternoon nap as the second phase, then yes. Otherwise, no. The whole medieval "second sleep" thing was probably a cultural thing and not a biological thing and it seems to have been limited to Europe during that time period.
Jared Diamond in "The World Until Yesterday" says that when he was on expeditions with natives in New Guinea, they would all go to sleep when the sun went down (near the equator so usually pretty close to 7pm), then wake up around midnight and chat for an hour or two around the fire, before going back to sleep again and waking up at sunrise (again around 5 or 6).
That's 10 hours of sleep at night? Or are you being euphemistically and are you including time spent on sex?
7-12 (5 hours sleep) 12-2 (2 hours chatting around fire) 2-5 (3 hours sleep)

How are you doing the math here? I count 8 hours of sleep.