Bouncing around in the water might seem more like play, but it can also be a challenging activity. The water creates resistance that makes your muscles and heart work harder for a great calorie-burning workout. Also, many people report enjoying water-based exercise more than land-based exercise. Because of this you may be able to work out for longer and burn more calories.
Calorie burning is a complex subject. It's influenced by so many factors -- including genetics, gender, body weight, intensity -- that it's difficult to give more than a vague estimate. According to Harvard Health publications, a person weighing 155 pounds will burn about 300 calories in an hour of water aerobics. That's similar to the number of calories burned in an hour of weightlifting or moderate calisthenics.
If you want a more accurate assessment of the calories you burn during your favorite water aerobics class, wear a fitness monitor. Just make sure it's waterproof.
Burn More Calories
Three hundred calories in an hour doesn't seem like much, but you can increase your calorie burn by working harder. Take classes that use weights, that move at a faster pace and include interval training. Interval training is a form of exercise in which you work at a high intensity for a brief period of time, then slow down and recover for an equal or slightly longer time. This type of exercise has been shown to be more effective and efficient at burning calories and fat than steady-state exercise, in which your heart rate remains constant.
Benefits of Water Aerobics
Perhaps more important than calories burned are the many benefits of exercising in water. Water reduces a person's weight on land by about 90 percent, which means much less pressure on joints and muscles. For people who can't easily work out on land, such as obese people and those with rheumatoid arthritis -- water aerobics is one of the few options for getting cardiovascular exercise and the calorie-burning benefits that go with it.
While water makes you more buoyant, it also creates resistance. Water is denser than air, so moving through water is much harder than moving through air. This increases the challenge of the workout. Exercising in water will help you develop lean muscle mass. Having more lean muscle mass makes it easier to lose fat and keep it off. Water aerobics classes that use weights carry even more muscle-building and calorie-burning potential.