Almost nothing beats swimming when it comes to a low-impact aerobics workout. Although you can find water aerobics classes at a lot of gyms or swimming clubs, you don't have to take a class to reap its benefits. Try any of these 7 Water Exercise Routines the next time you want to hit the water for a good cardio workout. Water aerobics is also a wonderful exercise if you suffer from joint pain or arthritis or are recovering from an injury. Plus, anyone at any level can reap the benefits of water aerobics. How many calories you burn in water aerobics depends on your speed, weight and gender. To see how many calories you burn in water aerobics, use the calculator below.