Haha! Listen, the "you can do it if you believe in yourself" stuff always sounds bogus. But there was some stuff around ten years ago about this. Here's an example: https://www.pnas.org/doi/full/10.1073/pnas.1313475110#F1

I don’t think its completely bogus. There are lots of things you can do that you don’t realize you can. But 40-50 hours of work a week, even if you don’t even leave your house, still takes a lot out of you.