I’d like you to start by closing your eyes, taking a deep breath, and relaxing. As you find yourself slipping away into the world of your most relaxed state, I’d like you to picture yourself sitting down and getting comfortable… on a plastic chair in your doctor’s office.
Okay, now imagine what might happen to your blood pressure. Now you can open your eyes and come back to reality so we can learn about some of the pitfalls of measuring blood pressure and some ways to get more useful information out those numbers. After all, blood pressure – like age – is just a number. That number by itself is much less important that what that number is putting you at risk for over time: heart attacks, strokes, heart failure, and even death.
Did you know that the way your doctor is supposed to measure your blood pressure is by:
- Choose an appropriately sized blood pressure cuff
- Put the cuff about 1 inch above the crease of your elbow on your bare skin
- Have you rest comfortably with your back supported for 5 minutes without your legs crossed
- Measure the blood pressure with your arm and the cuff at the level of your heart and without any talking
- Measure your blood pressure 3 times, throwing out the first reading and then averaging the others
- Blood pressure in both arms should be measured at least once
I hope you had a good laugh because it’s actually quite rare for people to actually measure blood pressure like that. First of all, the average primary care visit in the US is only 17 minutes total so taking a third of that just to measure a blood pressure probably isn’t going to happen for most people. So you might ask, if blood pressure is so important and almost 1 in 2 adults in the US have high blood pressure, why aren’t we being more careful about diagnosing it?
Excellent point… I’m so glad you asked! Now we get into some of the controversy that the medical community has been debating recently, which may seem like a simple answer until you really think about it… how should we really define high blood pressure?
Did you know that your blood pressure fluctuates throughout the day and night? Your body regulates blood pressure based on your activity level, how warm or cold you are, whether you’re eating or sleeping, and more. For example, you might think a blood pressure of 180/90 is way too high, but that can be completely normal for someone who’s exercising. In light of this, there has been more interest in measuring blood pressure over the course of the entire day, called ambulatory blood pressure monitoring (ABPM). It provides much more detail than just 1 reading in your doctor’s office, which is thought to perhaps provide more insight into whether your blood pressure is actually putting you at risk for all those bad things it’s associated with when too high.
One recent study looked at how blood pressure measurements in either an office visit or by ABPM at home correlated with dying from heart disease and found some very interesting results. I know you’re excited to hear, so the short answer is that more people who died during the study had high blood pressure with ABPM than with office measurements. This means that while having high blood pressure may not be responsible for killing people immediately, it certainly contributes toward lots of other things that can, such as heart attacks and strokes. So if you have a diagnosis of high blood pressure… fear not! It doesn’t mean you’re necessarily going to die soon. It does mean you should take it seriously though to make sure it’s under good control.
Ok, now that you know the short answer, the more interesting part is in the details. There are a couple of groups of people who would intuitively be mis-classified by just checking an office measurement: 1) people with “white coat hypertension,” or people with high blood pressure in the office, but normal blood pressure outside the office; 2) people with “masked hypertension,” or people with normal blood pressure in the office, but high blood pressure outside. Interestingly, people with white coat hypertension had about the same amount of deaths as people with plain old high blood pressure all the time, but it was the group with masked hypertension who had the worst outcomes. This makes sense if you think about it… people with masked high blood pressure have a normal blood pressure in their doctor’s office so probably wouldn’t get any treatment, but as soon as they leave, they have high blood pressure the rest of the time.
Ok, so what do we do with this information? Well, not everyone needs to walk around with a blood pressure monitor on them all the time. However, it probably is important to consider that your blood pressure changes throughout the day and in different circumstances. The bottom line is if you don’t know about it, you certainly can’t treat it. Now comes the good part! This means that
you have the power to take your blood pressure into your own hands.
Measure your blood pressure yourself! Your doctor or pharmacist can help you learn how. Then keep a log of your blood pressures that you measure at home. Make 3 columns for the date, time, and your blood pressure.
You can bring it to your next doctor’s appointment and have a great discussion about how good your blood pressure really is.