There's a wide distribution of circadian rhythms in the human population between the poles of what are commonly called 'early birds' and 'night owls'. Those rhy

There's a wide distribution of circadian rhythms in the human population between the poles of what are commonly called 'early birds' and 'night owls'. Those rhythms mean that there is an optimal wake for each person that is not infinitely flexible. We cannot all sleep and rise with the sun and do our best work. In my case, I struggle to do serious work outside of 10am-10pm. I wake at 7am because of my partner, but for the first three hours of every day, my brain hardly works. I have to fill my time with other things - exercise, reading, chores, and so on. If left to myself, I naturally go to sleep at midnight and wake at nine, and feel better for it.