I don't think humans are so weak that they can't handle 60 hour weeks, but 90 is definitely too much. I agree very strongly with the overall idea of your post,

I don't think humans are so weak that they can't handle 60 hour weeks, but 90 is definitely too much. I agree very strongly with the overall idea of your post, but for me it is all about building the right kind of balance in my life so that I can have maximum productivity. For me, that is 70 hour weeks as a single fellow with a highly optimized life (premade meals, standardised routine etc)