The real problem, of course, is the word "sprint", which (whether you like it or not) implies something.
A sprint, be definition, is unsustainable.
It's Pythonic levels of hilarity that we adopted this word to describe software development. It's Shakepearean in the tragedy that so many defend it.
Choose another word, like, "jog", "amble" or similar, and you won't see the same level of backlash against it.