I often read while working out on a NordicTrack elliptical. Reading while working out really tests the quality of a book. The workout, 40-60 minutes of steady, heart-pumping effort, is unpleasant enough. The book has to engage me to the point that I forget I'm working out. That's a tough standard. I'm not as forgiving of lazy writing when I'm sweating and gasping and looking for something to take me away from it. I keep a stack of books nearby because I am known to toss books that fail the workout test across the room.