If you want a book full of studies on this very topic -- many of which show the perils, yes, of trying to do non-manual-labor for extended hours -- get the book

If you want a book full of studies on this very topic -- many of which show the perils, yes, of trying to do non-manual-labor for extended hours -- get the book Be Excellent at Anything, which is a misnomer. The book used to be titled The Way We're Working Isn't Working, and it was a huge overview of studies that show, well, the way people are working isn't working.