If it’s not obvious, this is intended for marginal genius types, or simulacra thereof such as mine own self. The idea is to maximize productivity by maximizing uptime and both energy and willpower during uptime.
Having established work as a typical, minimum concession to the extension of one’s productive, healthy lifetime, and recognized that in most cases it is the “fixed point” around which every other activity has to be adapted, I would encourage a person to add some other healthy habits to further increase their health. Even a modern Beethoven is well-advised to brush his teeth at least once on most days, though he strains at the bit to finish an important symphony. This is the basic strategy for going from level 2 to level 3, whose basic tactics are mostly related to increasing one’s health through good scheduling habits, diet, hygiene, exercise, good sleep habits, and so on.