Blood Pressure Changes from Common Activities

Everybody knows that certain things--lifting heavy weights, rage, anything connected with Rush Limbaugh--can raise blood pressure levels. (Limbaugh is an interesting case in that he seems to raise the blood pressure of people who can't stand him--but also seems to raise the blood pressure of his fans. Some media personalities need to be taken with a grain of salt, but Limbaugh is apparently the equivalent of about a handful of salt.)

What few people know--and scientists didn't know until the advent of ambulatory blood pressure monitoring--is how much blood pressure can be increased by normal, everyday activities. Chances are your doctor isn't aware of these facts, either (otherwise they wouldn't talk to you when they are taking your blood pressure).

Below is a table that lists the average change in blood pressure from everyday activities. Perhaps you won't be surprised that attending a meeting can raise your blood pressure by 20/15 (I've been to some that surely raised my blood pressure more than that). But the process of eating raises blood pressure by about 9/10. Getting dressed jumps it up by about 12/10.

Merely talking to someone raises blood pressure on average by 7/7 (and talking to doctors and nurses is probably a little more stressful than talking to, say, your grandmother). Talking on the telephone is even worse--a jump of about 10/7, even if you aren't talking to a telemarketer.


Unfortunately there is no data on what happens to your blood pressure when you have to listen to someone else yammering on their cell phone, but I'm guessing this gets as high as 30/20.

This underlines three major points. First, your blood pressure fluctuates a great deal during the course of a normal day. The idea that any single measurement tells you your average blood pressure is clearly incorrect. Blood pressure jumps around from moment to moment.

Second, since all of the scientific recommendations on hypertension are based on relaxed, resting blood pressure, without any of the seemingly innocous activities listed above, you need to be aware that blood pressure measurements taken without full relaxation, or while talking, or reading, or watching television, are probably too high to reflect the scientific benchmark.

Third, given all this varability, it is wise to be very suspicious of "trends" identified by your doctor. If your blood pressure is up, say, five points from your previous visit, does it really mean anything? Was your reading taken perfectly this time? Did you have time to relax, and five minutes without any distractions such as conversation?

This is the reason home monitoring is so important; a handful of measurements made under imperfect conditions at your doctor's office shouldn't be allowed to determine everything about the course of your treatment.

But it's your responsibility to make sure those home measurements are taken correctly.

White-Coat Hypertension, Panic, and Blood Pressure

"White-Coat Hypertension" is defined as a diagnosis of high blood pressure based on clinical measurements in people who do not have high blood pressure outside the doctor's office. It is commonly accepted that white-coat syndrome occurs in about 20% of all people diagnosed with hypertension [1]; some have speculated that the frequency may run as high as 30%. This means that somewhere between one in five and one in three people being treated for high blood pressure actually has normal blood pressure.

For a time, some in the medical community contended that white-coat hypertensives should be treated with medications, arguing that either 1) these patients probably suffered damage from such surges in blood pressure, or 2) that people with white-coat hypertension would probably go on to develop true hypertension. Both of these beliefs have been shown to be incorrect in the case of the vast majority of patients. The dangers and extra costs of unneccessary medication are now considered to outweigh any benefits from treating typical white-coat hypertensives.

In a previous post, I discussed many reasons that doctor's-office readings tended to be high. On top of these procedural errors by medical staff, many people experience considerable anxiety in doctor's offices (often without realizing it). Certainly very few people would list a doctor's office or hospital as the most relaxing environment they can imagine. (Although there is a very small percentage of patients who exhibit what is called "masked hypertension." These people for some reason show lower blood pressure in doctor's offices, and higher blood pressure when out in the real world.)

Strictly speaking, "white-coat hypertension" applies only to those patients who have normal blood pressure outside the doctor's office. But the effect seen in white-coat hypertension--a jump in measured blood pressure of up to 23 points systolic and 10 points diastolic--also exists in people who have high blood pressure.

For example, consider a patient who has a blood pressure of 160/95. Now, that's hypertension by any definition of the term. But that same patient may get readings in a doctor's office of 180/105, which is rather severe hypertension. If this effect persists, then even after treatment and medication that has reduced true, out-of-office blood pressure to 120/80, this patient will still read as 140/90 on doctor's visits, which will probably result in additional medications being prescribed.

As far as I can tell, there's no name for this effect. It's probably a kind of panic disorder. Whatever its name, I have it. I can take a blood pressure reading in my car out in the parking lot, walk into the doctor's office, and promptly get a second reading 20 points higher systolic, and 8-10 points higher diastolic.

I first discovered I had hypertension when they took a routine blood-pressure reading at an urgent-care clinic. Although higher blood pressures are commonly found during illness or after injury, mine was 185/111. This sent the staff into a tizzy, and they insisted I couldn't be treated for my injury, or in fact be allowed to leave, until my blood pressure came down. "This is a medical emergency," they said. "You need to relax!" Being told that you're in a medical emergency isn't the most relaxing thing in the world, and naturally they managed over the next hour to push my blood pressure higher and higher, topping out at 221/121.

It isn't something so simple as a fear of doctors. It's somehow a fear of the measurement itself. Researchers working with ambulatory blood-pressure monitoring have found that many patients with white-coat hypertension have a jump in blood pressure when they measure it themselves, though the rise is much smaller. Someone whose blood pressure leaps by 20 points in a doctors office may get readings 5-10 points too high taking their blood pressure themselves in the comfort of their homes.

It has long been known that panic disorders can raise both systolic and diastolic blood pressure readings. One study found that systolic pressures could rise as much as 36 points [2]. There is a widespread myth in the medical community that panic attacks only raise systolic blood pressure, but this belief is false; diastolic pressure doesn't jump as high systolic, but increases of 5-10 points in diastolic pressure are not uncommon.

Many people find the squeezing of the blood-pressure cuff around the upper arm to be unpleasant or unnerving. If the patient is concerned about the outcome of the reading, the continual increasing pressure tends to raise the level of concern; in my own case, when the cuff continues inflating for what seems like a prolonged period, I begin to wonder, "My God, how high can my blood pressure be, anyhow?" and my heart begins to hammer. In effect it becomes a race between the cuff inflation rate and my increasing blood pressure, and the longer the cuff takes to inflate and begin deflation, the longer my blood pressure has to gather itself together and rise too damn high.

Okay, so maybe I'm weird. But as it turns out, this isn't just a problem for for me. Studies have found that overinflating cuffs raises systolic blood pressure, even in those who aren't nervous and don't perceive the cuff as being overinflated [3]. Although I haven't seen any studies on the trend towards autoinflating cuffs, these new automatic devices often wildly overpressure the patient's arm. What's worse, they often do it in stages, tightening to what seems like an intolerable level and then "listening;" and then deciding that the pressure is still insufficient, swelling even further and further. Overtightening in and of itself raises blood pressure, and I'm certain that any careful study would show that taking extra time to overtighten raises blood pressure even further.

I now ask the doctor or nurse to measure my blood pressure with manual inflation, since human beings are far less likely to overinflate the cuff. Ironically, though, many hospitals and HMOs now insist on the use of automatic blood pressure cuffs "to eliminate human error." The result is usually that someone comes, straps you into a cuff one size too small for your arm (resulting in an artificially high reading), the machine overinflates (resulting in an artificially high reading), and then spends too long deflating (which, if you are at all prone to anxiety over the result, also results in an artificially high reading). No wonder blood pressure problems seem to be on the rise across the nation.

Your mind can influence your blood pressure strongly in a matter of seconds. When you think about it, this makes sense: when a saber-toothed tiger leapt out from behind a bush, your ancestors didn't have time to wait around for a gradual increase in their blood pressure before responding; your blood pressure has to be able to leap even faster than that saber-toothed cat.

Wrapping a blood-pressure cuff around your arm certainly isn't as vivid an experience as having a predator attack you, but medical people nowadays do their best to frighten people about the dangers of hypertension. I'm sure this is all well-intentioned--doctors and nurses complain that they see too many patients ignore high blood pressure and then go on to have debilitating strokes a few years down the road. But for those of us who are of a less phlegmatic disposition, they succeed in turning every blood pressure reading into a situation fraught with life-and-death implications.

I always take my own blood pressure three times, and I've noticed an interesting trend. If my first reading disturbs me--if it is higher than I'd like--then then next two readings climb even higher. On the other hand, after a good initial reading, each successive reading will tend to be lower as I relax with relief.

Everyone with hypertension ought to be aware that their readings might be strongly influenced by psychological factors, and that doctor's-office readings may be biased strongly upwards. I wish I could offer a reliable cure for this problem, but I don't have one (though I will discuss the problem and possible solutions further in future posts). I can offer this one element of hope: If a big part of your blood-pressure problem is in your mind, then you may be able to cure yourself much more quickly than if it were simply physical.

[1] Pickering, Thomas G., White Coat Hypertension: Time for Action. Circulation. 1998; 98:1834-1836.

[2] White, William B., and Laurence H. Baker, Ambulatory Blood Pressure Monitoring in Patients With Panic Disorder. Arch Intern Med. 1987; 147(11):1973-1975.

[3] Kugler, J et al. Rise in Systolic Blood Pressure During Sphygmomanometry Depends On The Maximum Inflation Pressure of the Arm Cuff. J Hypertension. July 1994. 12(7):825-9.

Why Your Doctor's-Office Blood Pressure Readings are Wrong

Doctors are fond of referring to doctor's-office measurements of blood pressure as "the gold standard" for making decisions about the diagnosis of hypertension and the success of treatments.

In fact, measurements made in a clinical setting are probably the most misleading blood pressure data taken.

Here are the guidelines (as stated by the National Institutes of Health [1], the American Heart Association [2], and other organizations) for taking proper blood pressure measurements:

1) The patient should be seated and should rest and relax for five full minutes before the measurement is taken.

2) The patient should sit with feet planted on the floor.

3) The patient's arm should be supported at heart level.

4) The blood-pressure cuff should have a bladder large enough to encirle 80 percent of the arm.

5) The patient should not be engaged in conversation during the measurement (and probably not during the five-minute rest period, either).

It's not uncommon for measurements taken by a nurse or doctor to violate all five of these guidelines at once. In fact, three research projects showed that no physicians studied followed all of the American Heart Association guidelines for measuring blood pressure, and few of them were followed at all [3]. Think about it:

1) Five minutes rest before the measurement is almost never given. Five minutes rest doesn't mean sitting in the waiting room and then being summoned to an immediate blood pressure test. It means sitting and resting in the chair where the blood pressure will be taken. This can make a huge difference, and, for most people, the sooner their blood pressure is taken after sitting down, the higher their blood pressure will be. It's common for the readings to drop by 5 points with a few miutes of rest; for people who are apprehensive or have "white-coat syndrome," some slow breathing and relaxation can drop the readings by 10 points or even more.

2) Hop up on the exam table! What does it matter if your feet dangle?

3) And, again...hop up on the exam table! Your arm doesn't really need to be supported, does it? Well, according to Pickering, et al [2], "The position of the arm can have a major influence when the blood pressure is measured; if the upper arm is below the level of the right atrium (when the arm is hanging down while in the sitting position), the readings will be too high. Similarly, if the arm is above the heart level, the readings will be too low. These differences can be attributed to the effects of hydrostatic pressure and may be 10 mm Hg or more, or 2 mm Hg for every inch above or below the heart level." In other words, your arm position can make all the difference in whether or not your doctor decides you have hypertension and starts you on a course of medications.

4) The "standard" cuff is good up to an upper-arm diameter of 13 inches. That might seem like plenty, but it isn't; arm diameters higher than 13 inches are common in people who are overweight, and also very common in men who are carrying even a modest amount of muscle. (I am not overweight, nor am I very tall, nor am I built like a bodybuilder, but my upper arm diameter is more than 14 inches.) How much difference does cuff size make? In one study [4], using a cuff one size too small or large resulted in 30-40% of patients being misdiagnosed as hypertensive or normotensive.

A comprehensive discussion of cuff-size problems has been assembled by Kmom, whose website (though oriented toward the blood-pressure problems of pregnant women) provides a thorough overview, references, and plenty of anecdotes.

5) No talking? Ha. I have never, ever, no, not even once, had my blood pressure taken without the doctor or nurse holding a conversation with me. And why should it matter? According to research, talking raises blood pressure about 7 points above merely sitting and relaxing. Seven points might not seem like a big deal, but on average blood pressure medications only lower blood pressure by about 10 points. In other words, shutting up might have an effect nearly as large as taking a powerful medication.

Notice that most of these mistakes--taking blood pressure without a rest period, wrong leg and arm positions, using a cuff too small, and talking during measurements--tend to raise blood pressure. This means that for most people the blood pressure readings taken in a doctor's office are on the high side.

This has only been discovered since the advent of non-invasive ambulatory blood pressure monitoring (ABPM). ABPM systems are worn continuously (usually for 24 hours), and take blood pressure readings without an inflating cuff; the patient is unaware when blood pressure measurements are being taken. Data from ABPM have opened a whole new window on the topic of blood pressure. Blood pressure throughout the day varies considerably more than most people ever expected (and most doctors seem to be unaware of this fact).

One of the important discoveries is that--as might be expected from the foregoing--the blood pressures taken in doctor's offices tend to be higher than average blood pressures[5]. Most important has been the revelation of the extent of "white-coat hypertension;" on the order of 20% of patients diagnosed with high blood pressure have perfectly normal blood-pressure readings outside the doctor's office. And, although many doctors and nurses continue to believe that white-coat hypertension affects only the systolic blood pressure, both systolic and diastolic pressures can be affected: one study found rises of 9 to 23 mm systolic, and 3 to 10 mm diastolic [6]. (I'll have more to say about white-coat hypertension in a future post.)

In short, measurements made in your doctor's office are likely to be too high. If you really want to know what your blood pressure is, you'll need to measure it at home. Surprisingly, the American Heart Association, which long contended that the only reliable means of blood-pressure evaluation was clinical measurement, now recommends home monitoring as a critical corrective to the over-high measurements taken in doctor's offices.

In other words, even the doctors are beginning to realize their readings aren't accurate.

Don't think for a minute, though, that knowing this will prevent them from prescribing your medication on the basis of their office readings.

[1] National Institutes of Health, Blood Pressure Evaluation and Treatment, NIH Publication 03-5233. December 2003

[2] Pickering, Thomas G, et al, Recommendations for Blood Pressure Measurement in Humans and Experimental Animals Part I, Hypertension. 2005; 45:142

[3] Campbell, Norman R.C., and McKay, Donald W., Accurate Blood Pressure Measurement: Why Does it Matter?, CMAJ. August 1999; 161 (3) 277

[4] Sprafka, JM et al. The Effect of Cuff Size on Blood Pressure Measurements in Adults. Epidemiology. May 1991; 2(3):214-7.

[5] Pickering, Thomas G., White Coat Hypertension: Time for Action. Circulation. 1998; 98:1834-1836.

[6] Pray, W. Steven, Home Blood Pressure Monitoring, US Pharmacist. 2008; 33(2):14-17.