to me, you use more muscles than you would with other types of cardio and you are still keeping your heartrate elevated, so to me, it would def be as effective.
Shit the Rocky 3 avatar and the Rocky 3 workout. Will Apollo be at the other end of the pool telling you that you can do it? With Paulie saying you can't train to that jungle music?!
LOL all jokes aside, swimming is good for overall cardio health and to stretch the muscles a bit. I'd say 'go for it'
Ps. I would put a pic of Stallone from Rocky 4. I think he looked his best in Rocky 4 and Rambo 3. He went from being a blob in rocky 1 and rambo 1 to looking ripped up, then eventually ripped AND fairly big in the others. It's kind of odd that's exactly when Franco started to train him...hmmm I wonder what of 'supplements' he hooked him up with!