Writing is a cerebral process, but that doesn't mean that physical fitness is irrelevant. We think about the connection between creativity and bodily exercise, especially when it comes to discipline and the avoidance of malaise.
Haruki Murakami interview in Der Spiegel (2008): https://www.spiegel.de/international/world/spiegel-interview-with-haruki-murakami-when-i-run-i-am-in-a-peaceful-place-a-536608.html