…even if it were the case that schoolchildren's sleep cycles were dictated by the sun (which several comments in this section indicate isn't the case, and conta

…even if it were the case that schoolchildren's sleep cycles were dictated by the sun (which several comments in this section indicate isn't the case, and contain references which I suppose one could follow) … my school, for example, started at 7:50am. That meant waking up well before sunrise during some parts of the year (~70 minutes before sunrise, in the darkest portion¹). I remember always being very tired for first period … all the more amazing that I passed AP Physics, which I had first period. ¹(sunrise ~7:11a in the winter, we'd wake up at 6a. ~40m for breakfast/morning routine, ~1h for transit, and a little bit of wiggle, since you'd want to be there by ~7:40a at the latest.) (… and there are routinely threads on HN where people advocate for moving that wakeup to ~5a standard by futzing with DST.)