The asses-in-chairs owner I mentioned briefly had us discount time we spent on coffee breaks or on walks from our daily hours... exercise tends to encourage brain activity and for me specifically (I have ADHD) it has an extremely strong effect. Things slowed down for a while before senior management stepped in and said "Enjoy your coffee breaks and walks on the company time - be healthy!"

This is absolutely an anecdote - but I'm not certain how else to source data around this.