I find that as I age, the effects of lack of sleep get more and more severe. When I was 20, I could do 48 hours without sleep without any noticeable negative ef

I find that as I age, the effects of lack of sleep get more and more severe. When I was 20, I could do 48 hours without sleep without any noticeable negative effects, but now, 15 years later, I suffer even if I get sleep in a night but just not enough (where enough seems to be around the 9 hour mark if I really want to be at my best the next day; and I’m a firm believer of waking on a multiple of 90 minutes to wake during a light sleep cycle. 7.5 hours isn’t bad but 9 is better)