Or a cat who wants his breakfast at 5.00 am.
The best way to ensure you get up in the morning is to have children...
The best way to ensure you get up in the morning is not bother going to bed in the first place ......
I think it's bollocks. I've used a sleep monitor on my phone, which shows how much you move around, and the cycles are pretty random. They might average out at 90 minutes. But sometimes they're as long as 3 hours. It depends on a whole array of factors, like how much booze you've had, when you last ate etc etc.
The sleep monitor was quite useful as it woke you when you in the middle of a fidgety stage (REM?). Usually meant I woke up better.
Tuned into a 25 hour day? That's a bit silly then isn't it?
We had a 5:30 yesterday. What we get for letting him have a 2hr nap on Sunday afternoon I guess.
Why is it silly? The evolutionary process doesn't produce perfection, it produces something that works, which in this instance has been a periodicity of 25 hrs that gets reset each day when it needs to.