Acquire a really high level of fitness, the domain space is really large, interesting and rewarding. For example, obviously you need to learn plenty about nutr

Acquire a really high level of fitness, the domain space is really large, interesting and rewarding. For example, obviously you need to learn plenty about nutrition, then in order to make it meaningful you need to learn about cooking, then you want to work on your endurance, flexibility, muscle tone and strength, which means learning the muscle groups, then learning how each of the different gym machines will enhance your various objectives, then learning the various stretches for different muscle groups... its intellectual and rewarding. Anecdote: my personal trainer was talking about how an orthopedic doctor is his client, just because he's a doctor doesn't (apparently) mean he's mastered all of these domains.