Q: What are the basics of blood pressure, and at what point does normal blood pressure become high blood pressure?
A: Basically, blood pressure is produced by an active, living heart. You need that pump, the heart, to squeeze the blood. So when the heart squeezes the blood out, it pushes it out into the blood vessels. The peak of that pressure is the systolic pressure. The diastolic pressure is what we record after the heart valves have closed.
Q: How does high blood pressure damage the body?
A: High blood pressure damages the body by its effect, first of all, on the blood vessels: the big arteries, the medium-sized arteries and the small arteries. These are lined by endothelial cells, which help to protect and keep the blood in the vessels and help protect the rest of the body by preventing the material in the blood from leaking out. These cells [become] damaged, and eventually this leads to things like hardening of the arteries. At the micro-vascular level, it leads to blood in the urine, problems with the eyes, (problems) within the microcirculation of the heart and brain and just throughout the body wherever blood vessels are. Like a pipe that's been exposed to too much pressure, it can burst open, and that's when we see things like strokes that can occur in the brain. We talk about "target organ" or "end-organ damage"; these are the brain, the heart and the kidneys. High blood pressure damages the heart, and eventually [patients] develop hardening of the arteries. Arteries aren't as flexible and become narrower and narrower, causing heart failure and ischemic (inadequate blood supply) heart disease. Same thing with the kidneys, where we see kidney disease as a result of high blood pressure.
Q: In 2003, a national committee changed the diagnosis of high blood pressure, or hypertension, to include pre-hypertension. Why?
A: Blood pressure is probably a continuum. So at the points that they have labeled, high blood pressure is a continuum of the whole spectrum of blood pressure. At some point the specialists and different organizations have come together to say, "At this level of blood pressure, we're going to call this stage one [of high blood pressure], stage two, etc." Pre-hypertension is controversial. Some people don't like the term because you're putting a disease, a label, on to something that perhaps shouldn't be a label, and there's kind of a stigma attached to blood pressure. On the other hand, it's a useful tool, kind of a wake-up call for somebody who may be headed in the direction of developing high blood pressure. I don't think there's really been an agreement of the numbers, but it's probably somewhere between 125 and 140 on the systolic side that some people might consider pre-hypertensive.
Q: Why is high blood pressure called "the silent killer?"
A: It's asymptomatic. You don't feel it until it's too late. By the time you feel it, let's say when you have headaches, your blood pressure is going to be very, very high. Generally, each person is going to vary a little bit. Some people may be able to tolerate higher levels of blood pressure for a certain period of time before they feel the symptoms or develop the symptoms.
Q: Are there particular groups who are more susceptible to developing high blood pressure?
A: All of us, as we get older, develop some hardening of the arteries, and the result is our blood pressure, especially the systolic pressure, may go up. Racewise, African Americans have an especially high risk of developing high blood pressure. It's important that they get checked. If you have a family member with high blood pressure, then there's a chance there are genetic reasons for high blood pressure and familial reasons for high blood pressure. These people should be checked as well.
Q: What are the most effective treatments for high blood pressure?
A: If you're talking about pre-hypertension, diet and exercise are probably the most important. For diet, there is what is referred to as the DASH (Dietary Approaches to Stop Hypertension) Diet, which is a low-sodium, high-fruit and high-vegetable diet. And exercising at least three times a week for 30 minutes the more the better. For those with high blood pressure, we generally start off with a diuretic to remove some of the fluid and salt in the body. Then we might add other medications to that. There are some good medications today such as ACE, angiotensin-converting enzyme inhibitors, which help to protect the endothelial cells. The angiotensin-receptor blockers, or ARBs, are good medications. Other common ones are calcium-channel blockers, beta blockers, etc.