The idea that sleeping in is lazy and self-indulgent while rising at dawn is virtuously ascetic?
Many bodily functions such as hormone production are affected by your circadian rhythm [1]. Ambient light also seems to have an effect on quality of sleep.
[1] https://www.nigms.nih.gov/Education/Pages/Factsheet_Circadia...
It matters a lot, especially if it’s 5 AM - 1 PM. In high school, I was an RF technician, testing the rollout of LTE in my area. We had to conduct drive tests at night, due to traffic concerns. Working at night and sleeping during the day seriously disrupts your natural circadian rhythm. The only reason we as humans don’t sleep immediately after sunset is due to the invention of artificial light.
I think the quote is more an aphorism than rigorous guide. The framers of the quote probably didn’t anticipate the night shift ;)
I don't know about some people, but for me this is practically the silliest thing I've ever heard.
I need 8 hrs of sleep period, and the time of day has zero effect on my alertness. It can be 9pm-5am or 3am-12pm, it's exactly the same.
But if I get only 6 hrs of sleep? I'm miserable.
I can't even begin to imagine where the idea that the hour of the day matters would have come from.
And just think of nighttime workers. Obviously their daytime sleep counts...