Sometimes people get excited about a new class and over train. My advise would be to cut back to 2 classes a week and supplement with other training. You should be doing this for yourself, not to impress anybody. I swim a lot in the summer. Kevin, yes, it is if you swim fast enough to get your heart rate to the target heart zone.
Swimming is a great way to develop elongated muscles.
It's also great for rehabilitation or anyone coming back from an injury. You need a Kiana Fitness Band. If you're traveling you can call ahead and find out what they do have. With the fitness band you can do everything from lunges, tricep kickbacks, curls, you can even take it to work. We also just produced a video that goes along with it.