Tennis, squash, racquetball, and handball can all provide excellent workouts, developing cardiovascular health, flexibility, and strength. However, if you're a beginner, it might be hard to to get the full aerobic benefits from any of these activities, if you have to spend much of your time on the court chasing balls. Of coruse, you can certainly count chasing balls toward that hour a day of "puttering about" that we should all aim for. But you probably shouldn't count your time on the court as more intense aerobic activity until you've become reasonably accomplished and can keep ball-chasing to a minimum. Because squash, racquetball, and handball are all played in enclosed courts, though, it will probably be easier for beginners to get a sustained aerobic workout, even early on, because it's easier to keep the ball in play.
Find out more about this book:Lifefit: An Effective Exercise Program for Optimal Health and a Longer Life