A book for the garage gym dad?

I recently started working out in my garage. A good deal of the time I spend on the indoor bike and it just so happens that I try and read while doing it.

At the moment I’m reading Meditations by Marcus Aurelius but what’s next? I’d prefer something short and pretty straight forward. I’m into for example nature, exercise, spirituality and parenting. I prefer fiction but tend to end up with non-fiction.

Please help me out.

by Writer-105