BIOMARKER #2: Blood pressure

We’re talking BIOMARKERS again this week (and for the next few weeks). Biomarkers are, you might remember from last week’s post, statistical snapshots – based on solid research – that can help us determine how old our bodies are. Which is, birthdays not withstanding, how old we really are.

Last week I wrote about resting heart rate. This week’s biomarker is blood pressure.

First, a little primer: Blood pressure is the force of blood pushing against the walls of arteries. Blood pressure measurements are given in two numbers. The first number (systolic blood pressure) is the pressure caused by your heart pushing out blood. The second number (diastolic blood pressure) is the pressure when your heart fills with blood. The safest range, often called “normal” blood pressure, is a systolic blood pressure of less than 120 and a diastolic blood pressure of less than 80. This is stated as 120/80. Elevated blood pressure increases the risk of heart attack and stroke and, if left untreated, can reduce life expectancy by 10 years or more.

An increase in blood pressure has always been taken as an inevitable consequence of aging. But what it is, is a consequence of a progressive lack of elasticity of the arteries along with a weakening of the heart muscle. So are those changes the natural, inevitable consequences of the passage of time?

Some artery “hardening,” and thus some elevation in blood pressure (the systolic number), may come with age as well as some (perhaps small) lack of efficiency in the heart muscle. But it is not so much the passage of time as the accumulated effects of unhealthy living that lead to high blood pressure. And, of course, it’s the usual suspects, the poor habits that have become increasingly ingrained in western culture.  You know what they are, folks: smoking, consuming high (bad) fat food, eating foods high in sodium, weighing more than is healthy and not exercising.

Normal, or not-scarily-low blood pressure (achieved without medication) is a sign of a strong, efficient heart and healthy, elastic arteries. Normal or lower blood pressure, then, is a biomarker for youth. Maintaining a consistent “normal” reading for systolic pressure as the years go by is a biomarker of youth. So aim for under 120/80. Forever.

There is, however, a measurement problem. We all get our blood pressure checked when we go to the doctor’s office. It doesn’t matter why we’re there, that’s the first thing that’s done. But that reading may be falsely high. We’re generally not thrilled to be at the doctor’s office. We’re worried or concerned, which means we’re stressed. And we probably cooled our heels in the waiting room for a while. Also a stressor. And we’re wondering just how much the insurance will pay.

Here’s what I do to try to get a good reading: I ask the nurse to give me a moment before wrapping the cuff around my arm. I sit up straight with my feet firmly planted on the floor and take several big, deep breaths. I relax my shoulders, place the palms of my hands on my thighs and close my eyes. Just for maybe 15 seconds. I’ve tested this more than a few times, first getting the immediate measurement, then mindfully relaxing. It’s pretty astonishing. Try it.

You can’t use blood pressure as a biomarker if the number you’re getting is physician-assisted high blood pressure.