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Aerobic exercise that goes swimmingly


When it’s time to exercise, many of us get out the sneakers and plan on getting hot and sweaty. But there’s one kind of aerobic exercise that keeps you cool – swimming. And it comes with some benefits you don’t get from land-based exercise.

This week on “Take Care,” Dr. David Tanner, an expert in exercise physiology and human performance, talks about the health benefits of swimming. Tanner teaches in the Kinesiology Department at Indiana University and is the co-author of "Swimming Past 50" and co-editor of the “Handbook of Sports Medicine and Science: Swimming.”

Tanner says that any exercise you can do to improve cardiovascular health is a good idea. Much of the body’s aging process is caused by inactivity.

But swimming in particular can help slow the aging process. Tanner said for the last 11 years, researchers have studied “master swimmers,” adults who have achieved that designation by swimming a certain amount and who often compete in swimming.

The studies have found that people who swim 3-5 times per week have an increase in muscle mass compared to the general population. Also, when you measure a swimmer’s biological age compared to their actual, chronological age, their biological age was 20 years younger, says Tanner. The biological age is calculated by measuring a series of biological markers and functions.

Swimming has also been shown to improve cognitive function, according to Tanner. And regular recreational swimmers have demonstrated better balance and muscular coordination, even when standing.

Tanner says there are other advantages to swimming – it’s safe, in that you don’t have to worry about traffic or cars like when you’re running or biking on a road; and there’s an important social factor when you’re exercising in a close space like a pool, so you bond with people and make friendships.

So how much swimming do you need to do to reap the health benefits?

Tanner says the guideline for how much to swim follows the recommendation for how much aerobic exercise adults should get -- half an hour a day, five days a week.

Serious swimming involves rhythmic breathing. And Tanner says that’s one of the major differences in swimming versus land-based exercise. When a person is running or cycling, for example, they breathe in normally and exhale quickly. But swimmers breathe in quickly and tend to exhale slowly while their face is in the water. So the exact opposite to exercising on land, says Tanner. Also, swimmers tend to keep their lungs fuller because it helps them float. Both these factors mean swimmers tend to have better pulmonary function, says Tanner.

For those of us who are exercising in an effort to lose weight, Tanner says the amount of calories you burn is similar to any aerobic exercise. One mile of swimming burns 400 calories, on average. And Tanner says one mile of swimming is equivalent to four miles of running. But, Tanner cautions, there’s a huge difference in each swimmer’s efficiency, depending on their level of expertise. The more efficient a swimmer you are, the less energy you will use.

One issue with swimming is that it doesn’t cause your appetite to be suppressed like other forms of exercise. Tanner says that’s because with exercise like running, your body gets hot, and stays hot for awhile after you’re done. When your body temperature is high, you don’t have much of an appetite. When you swim, you can sweat, but your body stays cooler, because of the conductivity of the water. So you have to guard against eating too much after your swim. The calories you burn are the same as land-based exercise, but you might blow all that hard work because you may be hungrier afterwards.