Water fun

Give me a big, fat star because I had a great workout at water aerobics today!!

Wonder what my heart really does during this workout?  I have seen the estimation to be around 315 calories burned in a typical 60 minute water class, but since I try and focus on interval training and getting my heart rate up 4 -5 times a class, I think an HRM will be my best indicator. I'm anxious to get to REI this coming weekend to purchase a new one, since my old one is leaky and broken.