Comment Re:Does staring at a Computer Screen all day count (Score 5, Interesting) 149
The conclusion here is that our chemical engines are too imprecise for us to evolve a dead-on circadian cycle. So instead evolution gave us an unaided circadian cycle that's calibrated with a mean of about 25 hours, so that people with a naturally extremely short cycle are still just over 24 hours, and it goes up from there. Then we get a natural reset cue to adjust the cycle every day to keep it in sync with the world. The primary component of the reset signal is sunlight exposure in the morning. If you get up at a reasonable time (near or after sunrise) and GET OUTDOORS for about 15 minutes, then you will feel like going to bed at the right time to get enough sleep and want to get up at about the same time the next day. We and our ancestors spent tens of millions of years with no choice but to receive natural light in the morning, so it was a pretty good system before we evolved to live in our parent's basements and stare at little screens all day.
I suffer big time from this - every day I want to stay up and get up about an hour or so later than I did the day before - but not if I'm spending much time outdoors, especially in the morning. When I'm backpacking, wholly cow do I just want to go to bed when it gets dark, and get up just after sunrise. If we spent the day exercising outdoors like evolution intended, we wouldn't have this problem... but good luck being able to/wanting to do that all the time. But if you just drag yourself out of bed and take a 15 minute walk outdoors, even if it's cloudy or right around sunrise, problem solved. It does get tricky if you have to be at work before sunrise. Or if you work night shift (which I did for about 2 years) you're just *'ed.
I think the light exposure causes melanin production on about a 14 hour delay, making us want top go to sleep about 16 hours after exposure. This is why melanin supplements near bedtime are somewhat functional as a surrogate for actual light exposure in the morning.
Or as an alternate solution, since the day gets longer by about 1.7 milliseconds per century, by my calculations you could just wait about 200 million years for the earth to get in sync with your natural clock.