OP here. Do you have a citation? The post is mostly to address this constant claims that 40 hours is proven by science and no convincing citations are provided

OP here. Do you have a citation? The post is mostly to address this constant claims that 40 hours is proven by science and no convincing citations are provided. I am also writing in the context of self-managing knowledge workers who can manage their own time. I explicitly write that the flexibility we have may mitigate many of the downsides observed in mandated long hours. For example, I do work >40 hours, but I rarely have to wake up with an alarm clock. I can follow the occasional 16 hour day with a 10 hour sleep cycle and stroll into work at lunch time the next day feeling pretty relaxed.