Comment by xnx

For these instances where I get urgently fatigued ("brain tired") in the daytime, I close my eyes and fall asleep in 1-2 minutes. I'm definitely unconscious. I don't set any alarm and naturally wake up in ~15 minutes. It's been as short as 8 minutes, or as long as 30, but probably averages around 15. "Body tired" is different and requires the normal multiple hours of sleep.