By Sarah Unke

About one in three adults in the United States has high blood pressure. The so-called “silent killer” can lead to stroke and heart attack, but once you know you have it, it can be controlled with things like medication, diet and exercise. That’s where tennis comes in.

While you should play in moderation and take precautions, you can still hit the court with hypertension, says Dr. Seth Feltheimer, internist at New York-Presbyterian Hospital at Columbia. In fact, if you have pre-high blood pressure, which is anything from 120–139 for the systolic or top number and 80–89 for the diastolic or bottom number, exercise, along with a healthful diet, can treat it, Feltheimer says. That’s because exercise strengthens the heart, reduces cholesterol and keeps arteries elastic.

Most cases of high blood pressure, which is a reading of 140/90 and above, can be controlled with medication, Feltheimer says. “Using medication and diet should allow the pressure to be stable,” he says, “allowing you to play tennis without any concerns.” See your doctor to find out what treatment would be best for you.

Take it from Billie Jean King, who was put on blood pressure medication almost a decade ago. “It’s important to exercise,” she says. “But people think that if you work out it will take care of hypertension; that’s not always true. You [may need] to be on medication and try to keep your weight down.”

One precaution you should take as you play, Feltheimer says, is to stay hydrated. If you have pre-high blood pressure, your pressure will go down as you get dehydrated and you could pass out. And if you have high blood pressure and are on medication, you need fluids to spread the drug through your body. To replenish electrolytes you lose through exercise, Feltheimer recommends flat mineral water to his hypertension patients because it has no calories.

Feltheimer also suggests checking your blood pressure with a home monitor (see right) if you have hypertension. Check it before and after you play and at certain times during the day to make sure it’s where it should be.

The scariest thing about high blood pressure is that it has no outward symptoms and many don’t know they have it. So healthy adults should start getting blood pressure screenings in their 30s, and earlier if they have a family history of hypertension. And to help prevent high blood pressure in the first place, maintain a healthy diet and keep hitting the court.

Originally published in the November/December 2009 issue of TENNIS magazine.