The forgotten half of the 10,000 hours to mastery popularized by Malcolm Gladwell, as argued by Alex Soojung-Kim Pang in Rest (emphasis mine):
“Deliberate practice,” they observed, “is an effortful activity that can be sustained only for a limited time each day.” Practice too little and you never become world-class. Practice too much, though, and you increase the odds of being struck down by injury, draining yourself mentally, or burning out. To succeed, students must “avoid exhaustion” and “limit practice to an amount from which they can completely recover on a daily or weekly basis.”
We should try to remember that we call it practicing medicine for a reason.