Contents Under Pressure
More than 70 million Americans are living with hypertension. Many do nothing about it, and many don’t know they have it—even as it registers a heavy toll on the body.
When cardiologist William Tansey, MD, FACC, explains to his patients the best way to think about blood pressure—essentially, the pressure of blood against the walls of the arteries—he steers away from medical jargon and body parts and instead asks patients to think about their homes.
“Just as you have to maintain certain water pressure in your home, lest you burst pipes, you need to maintain certain pressure in your body,” Tansey explains. “You need a certain amount of pressure to get nutrients to all of your organs. Your body has a regulatory mechanism to ensure it has the right pressure for it. Over time, those regulatory mechanisms may become upset, so the body fills itself with pressure that is higher than it should be. In your house, that would be like the water coming out of the faucet, filling up the sink, and overflowing onto the floor.”
Suddenly, the picture is clear. And just as you’re imaging all that water and all that mess, you should be imagining the mess that the excess pressure—of blood, not water—is exerting on your body.
Understanding High Blood Pressure
Blood pressure is expressed in two numbers because it results from two forces. One is created by the heart as it pumps blood into the arteries and through the circulatory system. The other is the force of the arteries as they resist the blood flow. So if a doctor or nurse tells you your blood pressure is 120 over 80, just what does that mean anyway?
The higher figure, or systolic number, represents the pressure while the heart contracts to pump blood to the body. The lower figure, or diastolic number, represents the pressure when the heart relaxes between beats.
The American Heart Association (AHA) considers blood pressure below 120 over 80 mmHg (millimeters of mercury) optimal for adults. A systolic pressure of 120 to 139 mmHg or a diastolic pressure of 80 to 89 mmHg is considered prehypertension and should to be watched carefully. A blood pressure reading of 140 over 90 or more is considered high and may require treatment. In most cases, a person with high blood pressure is unaware of their condition; it usually presents without symptoms.
“People like to say, ‘Tell me my number,’ ” Tansey says. But he reminds patients that blood pressure is always in flux, depending on activity level, emotion, and anxiety. In fact, Tansey says that blood pressure is not about a single reading at all. “We want to get people to realize that they’re not going to explode because their blood pressure is high one day,” he says. “But if your blood pressure steps up for a protracted period of time, it’s a problem.”
And here is where the problem lies: Over time, elevated blood pressure can lead to a host of other problems, including chronic kidney disease, coronary artery disease, an enlarged heart, a heart attack, or a stroke. “When we talk about hypertension,” says nephrologist Jeffrey Feldman, MD, “we think in terms of ‘target organ damage’ to other areas of the body like the heart, kidneys, and brain. That’s why it’s incumbent on the doctor and patient to get blood pressure down."