Body-Clock, based on what? The Witching-Hour?

I have a pretty standard routine of: work/home/sleep/home/work, like most of us.

I awake, at about the same time, usually within a span of 10 minutes, every night, if my routine is on schedule.

I, and with using: “I”, I mean the shit that is running my brain, compensates for Daylight-Savings-Time within a week.

I eat some sort of candy/chocolate before bedtime, to ward off nightmares, so it could be a metabolism of sugars that completes around 3am, assuming my bedtime is met.

It is nothing new, I used to awake at 2am, on a daily basis, 20 years ago, and smile because I had at least 4 or 5 more hours of sleep. So it has been a lifelong thing.

Sometimes I will hit a “streak” where I wake up at like 3:08am for 6 days in a row. It has happened numerous times.

So how does a body-clock work? Kramer’s did, until the day of the race.
Just sayin’.

I can’t exactly answer your question, but I can give you this little nugget:
The brain has about 20,000 neurons that make up the internal clock. When the neurons are separated (like in a petri dish) they get out of sync, when they are all connected together they stay synchronized. That’s all I’ve got.

Let’s see:
DHEA increase ACTH production
ACTH induces waking
Neuropeptide Y promotes sleep and inhibits ACTH and cortisol release in young men

Nope, whatever the answer to your question is, it’s going to turn out to be complicated and obscure.