Stem cell researcher Dr Cristina Lo Celso talks the Academy of Medical Sciences about her work, and rest. This bit in particular jumped out at me:

I have learned not to feel guilty whenever I close the laptop to watch a movie or try some new recipes. Usually the best ideas come during or after breaks, and things that take hours to work through when I am tired will likely be solved in minutes once I am rested.

I think for lots of us, learning to not feel guilty when you stop work will have a ring of familiarity to it.

Lo Celso also has a nice bit about “learning to experiment outside the lab,” by trying new things in one’s non-work life. I’m convinced that one of the things doing sports can do for knowledge workers is give them a degree of physical courage, or ability to handle stress and discomfort, that translates into greater capacity for intellectual courage and risk-taking. (John Ratey’s Spark is great on the cognitive benefits of exercise.)