Swimming is a good exercise to improve your overall fitness, but myths abound that you cannot lose weight swimming. There is no magic to the formula for weight loss, though — if you burn more calories than you eat each day, you lose weight. Swimming burns a great deal of calories, but it does not leave you worn out like some other forms of exercise.
Swimming is an aerobic form of exercise, meaning that you use all your major muscle groups, and your heart and breathing rates increase, too. Aerobic exercise builds your endurance and cardiovascular health in addition to burning calories. You work harder to move forward in water than on land, because water is denser than air. You must overcome the resistance of water itself, and deal with the turbulence you create when you move through it.
Women actually benefit from having higher levels of body fat when they swim. You are more buoyant in the water than most men, particularly in your lower body and legs. You expend less energy just staying horizontal in the water and not sinking down and are more efficient in the water than leaner swimmers. Women excel at endurance swims for this reason, and also fare better swimming in colder temperatures because of the extra insulation they naturally have.
How many calories you burn swimming depends on how much you weigh, how long you swim, and the intensity of your workout. You burn 413 calories per hour swimming slow freestyle if you weigh 130 lbs. You burn 493 calories if you weigh 155 lbs. When you pick up the pace and swim fast freestyle, you burn 590 and 704 calories if you weigh 130 and 155 lbs., respectively. Breaststroke takes a lot of energy, even if you swim slower, so you burn the same number of calories per hour as you do swimming fast freestyle.
Swimming does not suppress appetite like some other forms of exercise, in part because of the cooling effect of water, says Alicia Kendig, M.S., R.D., and swimmer in “Swimmer” magazine. Typically, you emerge from a swimming workout very hungry. Bring along a small healthy snack, such as a yogurt or some nuts, to quell your hunger pangs after you get out of the pool, and keep a watch on the number of calories you eat each day.
Always check with your doctor before starting on a new exercise routine if you have any health concerns or existing health conditions. Some people experience eye and skin irritation when they swim in indoor pools, so try outdoor pools if the weather permits, or find a pool that has better ventilation, and better maintenance.