To lose weight, you have to burn more calories than you're consuming. To be more precise, you have to create a 3,500-calorie deficit in order to shed 1 pound of fat. One way to do that is to reduce the amount of calories you're consuming; the other way is to burn calories through exercise. According to MayoClinic.com, doing water aerobics will burn about 402 calories per hour for a 160-pound person; a 200-pound person, meanwhile, will burn about 501 calories during an hour-long class. By sticking to a water aerobics routine five days a week, you'll burn roughly 2,000 to 2,500 calories a week -- enough to lose 1 pound in less than two weeks.
Aquatic aerobics has another benefit that will help you in your weight loss journey: it's not just a cardiovascular exercise, but a resistance exercise as well. Your heart will beat faster and your lungs will take in a lot more air, meaning that aqua aerobics is indeed a "cardio" exercise. Yet, since your body is forced to move against the resistance of the water, it's also acting as a strength-training exercise, similar to lifting weights or doing pushups. Over time, that's going to change your body and make your muscles stronger, and perhaps bigger. And since muscle burns calories more efficiently, that added strength will help you lose pounds even faster.
Time and Intensity
When it comes to changing your body composition and shedding fat faster, time and intensity matter. Whatever type of exercise you do, whether it be water aerobics, swimming, jogging or anything else, you'll burn more calories the harder and longer you work out. When you're in that water aerobics class, don't just go through the motions with minimal effort. Instead of raising your arms above your head lackadaisically, really push through the water with intensity. Make more kicks in the water. Move faster. And if you have the choice between a 30- or 60-minute class, pick the longer one since it will help you burn more calories. You're already taking the time to get to the pool and change into a swimsuit, so you might as well make the most of it, right?
If you haven't yet chosen an aqua aerobics class, pay attention to the class format and the instructor's background as you peruse your options. According to the American Council on Exercise, good water-based classes should include a warm-up, a more intense cardio and conditioning section and finally a cool-down. Also ask whether your instructor is certified to teach aquatic exercise, as that can ensure you're spending your time wisely and joining a quality program.