Re:Show HN: Combining UTC and local times (time zones) in on...
by zamadatix on Wednesday October 20, 2021 @09:29PM
(#28939200)
My inquiry was not about or asking for proof of the idea people sleep at night rather why that info is preferred over more salient information as seen by continuing to the following, unquoted, sentence.
This is already answered in the post you are replying to, so I assume this is you demanding an external source:
https://www.wikiwand.com/en/Circadian_rhythm
https://www.wikiwand.com/en/Sleep