I wish they'd used hours after waking/before sleeping vs simply defining morning as between 4am and 12:00pm or evening as being between 5pm and 4:am People who

I wish they'd used hours after waking/before sleeping vs simply defining morning as between 4am and 12:00pm or evening as being between 5pm and 4:am People who wake and work later would normally drink coffee more often at later hours and there's already a bunch a research showing 2nd/3rd shifts can cause health issues which wouldn't show up in the people who get up at 5am and have a cup or two in the next few hours.