This is a common sports practice - to practice/train in the morning and then again in the afternoon. I feel like my work schedule encourages this philosophy. I wake up early. Put in a full work day, nap, and get another ‘day’ in. I can push myself to average 14 hours a day of work with a couple quick breaks.
It’s not sustainable - I couldn’t do this forever and I need days to recover. The best capital we have is the effort and energy we can input.