I’m a footwear designer, and I run (a lot), so am in a similar place as you. I find the key to balance is scheduling. I work for myself so am a bit more flexible (Thursday afternoon 30km run if I’m not busy, sure, why not), but mostly do normal work and know I’ve got runs every evening and long runs weekend. I also run with a crew at scheduled times so that helps. If you block in time for work and athletics and/or if your work can be more flexible, it helps. Maybe suggest to your boss you’d like to come in late 2x a week to do a morning run/swim if that helps clear your head and stay a bit later. Explain how it might help the creative process and give feedback on items of design?
Do you find you aren’t doing enough of what now? Design? Athletics?
I’ve found my sweet spot. Running is my number one passion and design is my number one love. I probably do both 50/50.
R