I agree with Dana, Pilates will not/does not count as cardio, but it is great for strength and stretching, building and using muscles in a different way. Strengthening your core will also assist you in doing other exercises and in just everyday life. The stronger your core is, the fewer issues you will have with pretty much anything else - esp. your back. Watch your back though, if you do anything that causes you pain (as in holy crap that hurts v. god this is hard) don't do it. A know people who gave up on Pilates because it can be hard on the back. Make adjustments and keep trying. Maybe a thicker mat will help too. On the Windsor version, she offers a safer back alternative. Good luck!