I have a fit spirit, mind and body.

Three things, and they rarely wear out at the same rate. Someone can run ten kilometers on a Saturday morning and still be unable to sit alone in a quiet room for ten minutes.

Fitness of the spirit has its own training: staying inside a hard conversation, admitting you were wrong, noticing something beautiful while exhausted. None of it burns a calorie. All of it takes conditioning.

The useful part of holding all three in one sentence is that they trade. A walk loosens a stuck thought. A settled mind gets you out the door on the morning you don't feel like it. Whichever one is strongest today can carry the other two a little way.