Around 30 percent of children in the U.S. don't get enough sleep: study
Lack of sleep was definitely the cause of my terrible grades in highschool mathematics. I would stay up late (1-2 am) to play in starcraft tournaments, to have 8 am classes in mathematics. (There's a neat inverse correlation between my highschool grades and starcraft rank)It's crazy to me just how terrible school systems are at optimizing for learning. I would get terrible headaches from classrooms that had too many people and too little fresh air. I thought it was just me dreading my lessons, but in reality it was from co2 ppm reaching levels that humans can't properly function in.We wake up students too early, put them in rooms that kill cognitive performance and then have the audacity to complain when they can't follow along!