For me, either I can’t fall asleep earlier no matter how good ‘sleep hygiene’ I have, how little screen time before bed, how long I avoid caffeine for, etc. or if I do fall asleep earlier because I’m exhausted I seem to get lower quality sleep and it gets harder and harder to wake up on time.

For me, it’s absolutely not a conscious choice, and it hasn’t changed depending on the level of stress I’ve been under, and I’ve tried all sorts of things across living in three different places over the years...

I eventually found sleep science research that suggests that it is just extremely difficult to go against your natural circadian rhythm. I guess the problem for delayed people (and if I recall the statistics correctly, the severity of my sleep cycle delay is such that it only affects something like 2-5% of adults, but I think more than 10 or 20 percent of adolescents) is that anyone can be lazy and sleep in, but it’s far, far harder to go the other way - so the majority of the population with a normal or early cycle can just go to bed earlier and function normally waking up earlier, but it doesn’t work for everyone.

It’s their bodies’ reaction to sunlight. There are plenty of nocturnal animals and plenty of diurnal ones. They don’t have clocks or screens to know when to wake and when to sleep. Neither did we until very recently.