An ideal circadian day involves being in bed for 8 hours consistently (within a 1-hour window) to achieve 7-7.5 hours of sleep.

“an ideal circadian day might be try to be in bed for eight hours consistently every night, when I say consistently, try to go to bed within an hour window, and be in bed for eight hours so that you can get seven hours, seven and a half hours of sleep if you're an adult.”