[LargoLasskhyfv]

5:30 AM in the same place, or different places? If same place, I'd assume some environmental/technical reason. Some machine somewhere near starting up, producing infra- or ultrasonics, a manifest freight train rumbling by far away, doing the same, some other thing (electro-/static/magnetic fields changing), and so on. 'Technical' because nature would vary that with the seasons because of https://en.wikipedia.org/wiki/Solar_time

[AnthonBerg]

Ah!! Thank you! Hadn’t thought of it that way. Aaand… When it happens, it’s 5:30 anywhere… in this timezone? I think? In other words, it happens in different houses in different parts of the country. (My thanks include the prompt to try to get this into words.)

It seems to be very tightly attached to the base circadian rhythm as attrained to the cycling daylight.

As far as I know, this time during night is very very likely to be the start of the cortisol spike that occurs before we wake up. The start of the wake-from-standby process.

https://en.wikipedia.org/wiki/Cortisol_awakening_response

Cortisol raises blood sugar, and histamine as an alertness neurotransmitter will then probably rise as far as I know? Have tried my best to understand this in order to escape the cycle when it starts; There seems to exist a rhythm in histamine release, and disrupting this rhythm seems to cause this 5:30 bs, haha.

[LargoLasskhyfv]

Could be, but wasn't what I had in mind/meant to say.

Local solar time means it's exactly 'high noon'/12:00PM when the sun is at its highest point in the sky. The farther away to the left/west or right/east (in the northern hemisphere(swap these if 'down' under)), the bigger the real difference in minutes would be. If moving up/down/north/south nothing changes. See https://en.wikipedia.org/wiki/Terminator_(solar) for why.

Meaning real sunrise would drift forwards and backwards in one location with the seasons/time of year, and also if you move left or right within that timezone because that is an artificial construct.

So I'm having real difficulties to accept a natural cause for that exactly 5:30AM :-) Something more technical, like machines starting according to some timetable/start of shift/schedule seems way more likely, because those are aligned to the artificial construct called 'timezone'.

Got it?

[AnthonBerg]

Ah, indeed – we’re on the same page! (I wish this wasn’t a belated reply…)

One thing is that I’m “forced” to pretty strictly wire my circadian rhythm to the societally defined clock.

This also defines much of what is the actual input into my circadian sensorium: Artificial light :)

I am able to have a remarkably consistent circadian rhythm, going to sleep arounnnnd, say, 11 PM? Waking up around 8-ish. Those times wiggle around a little.

It’s subtly tricky to put into words –meaning it’s interesting! — and I’m not even absolutely sure that this is everything that defines the machinery, but given this, uh, “framework”?, it’s ludicrously consistent: If I back my neuroendocrine system into a corner, it will bite at 5:30. Sometimes a bit earlier.

Thanks for the discussion! I hope we are actually on the same page w.r.t. premises and that I’m continuing this on the avenue you’re looking down!