To Your Health

Q. I exercise regularly, but my doctor recently said my blood pressure is too high. Why would that happen, and how can I control it?

A. Blood pressure is the amount of force required to push blood through the arteries and veins of the body. Under normal conditions the blood pressure stays within narrow limits, though it may rise during emotional or physical stress. The vast majority of people with elevated blood pressure have what is called "essential hypertension," because no single cause is found. Because many of the possible causes of hypertension (HTN) are interrelated, a defect in one component may disturb the normal function of another, and the combined abnormalities may then cause HTN.

One in four adult Americans has high blood pressure, and about one-third of these don't know they have the problem. You are fortunate that your physician found it, and you can now address the problem before it becomes serious. Early in the course of HTN the heart rate and heart output are increased, but eventually heart output decreases and blood is shunted away from the kidneys so that the heart and brain can continue to function. Kidneys interpret this change as a decrease in blood volume and act to retain sodium and water, which may then worsen the problem.

Your first step to restoring normal blood pressure, with your physician's advice, is to eliminate or reduce the risk factors you have the most control over: cigarette smoking, high alcohol consumption, obesity, and excessive salt intake. For instance, just 20 minutes after smoking a cigarette, the temporarily elevated blood pressure it causes will return to normal. Also, a modest weight loss can sometimes normalize blood pressure even if you do not reach your ideal weight.

Several antioxidants have been used successfully as part of the treatment for HTN. The best results have been obtained from coenzyme Q10 supplements of 200 to 300 milligrams a day. Along with coenzyme Q10 supplements, supplements of vitamins A, C, and E, selenium, and beta-carotene not only maintain the balance among the antioxidants but are also good for reducing blood pressure themselves.

Another useful lifestyle modification is a program of moderate exercise. Studies indicate that aerobic exercise such as walking, jogging, swimming, and bicycling can reduce blood pressure, even in the absence of weight loss. However, there is a quandary in that intense exercise can use up magnesium, which makes the HTN worse. Magnesium is vital for converting the body's fuel to energy during exercise. It is estimated that in normal circumstances, only 25% of Americans receive the 300 milligrams a day of magnesium recommended in their diet. Based on research showing depletion of magnesium stores during endurance training, 400 to 800 milligrams per day of magnesium is recommended for athletes. Scientists believe that endurance athletes are more likely to be deficient in magnesium as a result of an increased need while exercising and losses of magnesium in sweat and urine. This increased excretion represents 10 to 15% of total daily magnesium losses.

A diet rich in magnesium or a magnesium supplement might allow you to continue your exercise program safely without the risk of hypertension.