Driven by the unnatural setup of a high school schedule, I’d sleep 3-4 hours at night (3-6am), then arrive at school so exhausted that I was famous for taking a nap in almost every class. That meant an additional 1.5 hours of sleep, broken in to 15 minute naps spread across 6 periods. I got away with this because I graduated #2 in my class so could ignore teacher complaints about sleeping through slow lectures. But on Friday and Saturday, I’d sleep 10-12 hours, so my weekly average was between 6.5 and 7.3 hours of sleep per day. Not efficient and not very healthy. There’s also evidence that people under 20 need extra sleep. I also stupidly used Coke (the bubbly kind) for alertness.