HOW MUCH IS ENOUGH?

“Okay,” you say. “I buy what you say, but I’m a busy person. I’ve got a career, a family, other obligations. Just how much do I need to swim to keep my heart healthy?” The answer, say experts, is surprisingly little.

According to the AHA, a regular program of swimming—a minimum of thirty minutes at least three times a week—will improve the condition of heart, arteries, and lungs while lowering blood pressure, decreasing total cholesterol, and raising HDL. It will also lower your percent of body fat and help you lose weight. Four or five sessions each week will provide even better results. The American College of Sports Medicine suggests you swim fifteen to sixty minutes a day, three to five days a week.

A recent study published in the magazine Circulation demonstrated that only four thirty-minute sessions a week—two hours a week—reduced blood pressure by an average of six points for the systolic and ten points for the diastolic for a group of middle-aged, out-of-shape men with mild hypertension. And it only took ten weeks.

A study published in The New England Journal of Medicine found that people who are physically unfit have more than three times the risk of dying of a heart attack as people who are fit, regardless of their cholesterol levels, age, or whether they are smokers. How much do you need to swim to reduce your risk of heart attack threefold? “About 30 to 40 minutes, three to four times a week,” according to the study’s lead author, Dr. Lars-Goran Ekelund, associate professor of medicine at the University of North Carolina at Chapel Hill.

Two additional studies, conducted at the University of Washington, demonstrated that exercise such as swimming four times a week for forty-five minutes results in an increase of over 40 percent of the body’s production of tissue plasminogen activator, or TPA, the substance that dissolves blood clots that can block coronary arteries narrowed by atherosclerosis and precipitate a heart attack. Tissue plasminogen activator is a potent clot buster that is given in artificial form to thousands of heart attack victims each year. Moderate exercise, such as swimming, eliminates the need to take this drug.

Another recent study, this one conducted at the University of Massachusetts Medical School under the direction of Dr. Ann Ward, found that moderate exercise combined with a modest reduction in fatty foods produced major cardiovascular benefits in only four months. Ward’s subjects, overweight, sedentary, middle-aged men, dropped their total blood cholesterol by twenty-three points while increasing their HDL six points.

The list of such studies goes on and on. But Dr. Manuel Sanguily of New York, one of the top Masters swimmers in the world and an expert on the effects of exercise on cardiovascular health, sums it up this way: “If you’re one of the 60 million Americans who are at risk for a heart attack, the very best thing you can do for yourself is to start swimming.”