Hi all,
I took a few aquasize classes at my Y, as I want to do some cardio that won't stress my joints. Unfortunately my heart rate doesn't really raise during class, even when we're kicking our legs as fast as we can, or running in place. I work hard and my arm muscles are sore after class, but I don't feel tired or like I've done any endurance work at all. Maybe I'm just too used to water? All of the other women are huffing and puffing, but I'm always fine.
Is aquasize a good route to go for cardio? I don't really have many other options (even walking is **** on my ankles). Would ankle weights help? I don't use noodles, and I go into the deep end, despite the instructor yelling at me that it's too hard that way

I'd prefer to swim laps but aquasize takes over the pool during the time I can go.