Guest Author: Seth Kaplan
WHAT THE DOCS AND HEALTH COLUMNS WON’T TELL YOU
ABOUT BLOOD PRESSURE
“Blood pressure is a measurement of the force applied to the walls of the arteries as the heart pumps blood through the body. The pressure is determined by the force and amount of blood pumped, and the size and flexibility of the arteries. Blood pressure is continually changing depending on activity, temperature, diet, emotional state, posture, physical state, and medication use.”
You may not know it, but when your doctor examines you, he or she is doing a silent evaluation of how and what you present. When taking your blood pressure, for example, the doctor must weigh the reading(s) against your medical history, chronic conditions, family history, etc. A reading of 140/90 gets placed into that context, based on the doctor’s experience and intelligence. The conclusion will be different than the one arrived at for a patient with 120/80 but who has a different background and conditions.
This analysis becomes more complex when the Food and Drug Administration (FDA), American Medical Association (AMA), or other organization revises the general guidelines for interpreting blood pressure. If patients know what wheels are turning behind that professional — and seemingly objective — decision they can ask intelligent questions. The statement, “Everything looks fine!” may provide the opportunity to ask those questions.
More Than a Passing Interest
All of these factors occurred to me when I read an article in “The Well,” the health column of the New York Times. “High Blood Pressure Treatment Should Be More Aggressive, Study Finds,” by Nicholas Bakalar drew my attention as I have more than a passing interest in blood pressure (more on that later). I clicked on the link.
“The Well” page had tons of information, some new, some old. Definitions from A.D.A.M. Consumer Health, such as the one above, took up most of the space. Here are some basics. Blood pressure readings are measured in millimeters of mercury (mmHg) and are given as two numbers: systolic and diastolic. A typical reading, for example, is 110 over 70 (written as 110/70). The top number is the systolic blood pressure reading. It represents the maximum pressure exerted when the heart contracts. The bottom number is the diastolic blood pressure reading. It represents the minimum pressure in the arteries when the heart is at rest. But, there are more considerations for you to be aware of than are contained in this layman’s definition.
Understanding the Numbers
My interest lies in understanding the basic numbers provided above, especially as they influenced a couple of BP incidents in my life — one high and one low. The more you understand about which metrics are important and why, the better able you will be to ask the doctor questions. The nurse who initially takes your BP in the examining room prior to the doctor’s arrival may get one reading. The doctor, if he checks it again, may get yet another reading.
Bear in mind, too, that your doc will sometimes check your BP in both arms. If you pay attention while this goes on and ask about it, you will find out that two different readings resulted. I can remember getting my basic vitals recorded prior to a doctor visit. My BP was 90/50!! I said to the nurse, “I’m surprised I haven’t fallen over!” But, when the doctor checked it several minutes later, the reading had reverted to “normal,” i.e., 110/70, the second time consistent in both arms. Overdue for a sphygmomanometer calibration? You decide.
On the other end of the scale, one day at work I felt kind of “hasty,” and I developed a slight headache. When I checked my BP on a cuff at home, I found the cause. My blood pressure had spiked, producing a reading of 178/110!! Before my head could explode, I raced to the walk-in BP clinic at my healthcare provider. Much activity ensued, as you can imagine, with the upshot being that the doc put me on lisinopril, and, later replacing it with amlodipine, two of the many, many blood pressure medications.
Many things had changed between these two extreme examples, of course, but here are some metrics that your doc may or may not know. Asking about them may initiate an interesting discussion. Here are three typical questions:
- Does the difference between the two numbers mean anything?
The short answer is, “Yes!” Recall that 110/70 or 120/80 each has a delta of 40. That is okay. However, if the delta is >50, that could raise a question about calcification. About 60% of Americans have calcification.
- Is each individual BP number important?
If, over time, the diastolic, or bottom, number drops precipitously, that, too, could indicate calcification.
- Should I worry about a different BP reading in each arm?
If you take your BP in both arms every day for a week, and the difference between the two systolic (top number) readings is greater than 10, that may mean something untoward is going on in your cardio system.
If you don’t ask, you won’t know.
White Coat Syndrome
We all use the Internet and the media to learn more about our medical conditions. Thanks to the “white coat syndrome” this research can create, many of us often forget to ask what is the most important question when we go for an office visit. What that question is will change depending on how you feel but you can get too caught up in the details to remember it.
In addition, even informed patients—or healthcare consumers—sometimes fall into the self-diagnosis trap. You will be able to make the best use of the time you spend with the medical professionals who care for you if you learn the backstory behind the standard readings and can ask for more information about them from your doctor.