# Rethinking Normal Blood Pressure



## Ernest Nagel (Mar 10, 2011)

I suspect this would also significantly revise at least a few of the assumptions and projections re health care costs for the overweight to be lower? Has anyone reading this been diagnosed with prehypertension?

http://well.blogs.nytimes.com/2011/03/09/rethinking-normal-blood-pressure/

March 9, 2011, 5:40 pm
*Rethinking Normal Blood Pressure*
By TARA PARKER-POPE

Millions of people who have been told they are on the path to hypertension may never develop life-threatening problems, according to new research that suggests its time to redefine normal blood pressure.

The findings, from researchers at the Veterans Affairs Health Care System in Minneapolis and the University of Minnesota, suggest that as many as 100 million Americans who have been told they have a condition called prehypertension may face no added mortality risk and therefore could reasonably be considered to have normal blood pressure.

The authors reviewed two decades of blood pressure data that tracked 13,792 people from the National Health and Nutrition Examination Survey, which enrolled participants from 1971 to 1976. The researchers also reviewed similar data for 6,682 adults from a similar survey carried out between 1959 and 1962.

Current guidelines label people with blood pressure above 120/80 millimeters of mercury as having prehypertension and at higher risk for serious health problems like heart attack and stroke than people with lower blood pressure. But the data review found that people in that category are not any more likely to die prematurely than those with lower blood pressures, according to the study, published in The Journal of General Internal Medicine.

If we cant identify an increased risk, is that where abnormal should be set? said Brent Taylor, core investigator for the V.A. in Minneapolis and assistant professor of medicine at the University of Minnesota. It should at least start a conversation about why normal is set where it is. If we make small changes to where we set normal blood pressure, it has huge implications in the numbers of people we identify as being at risk.

The current guidelines were determined in 2003, when the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure issued its seventh report updating recommendations. The report was the first time that the panel identified relatively low blood pressure readings as an indicator of future disease. As a result of the findings, tens of millions of people were told they were at risk and were urged to adopt lifestyle changes to prevent blood pressure from creeping higher.

In the latest study, researchers focused on relatively older data because blood pressure treatment was not as prevalent years ago, and as a result, they could better study the health effects of changes in blood pressure as people age. Among people over 50, the most meaningful predictor of poor health was the systolic blood pressure  the first, or upper, number given in a blood pressure reading. In this older group, a systolic pressure of 140 or higher was most predictive of mortality. Among people under 50, it was the diastolic pressure, or second number, that was most predictive. In this group, a diastolic pressure of 100 or more was most predictive of poor health. In younger people, having a systolic reading of 200 or higher was also predictive of higher mortality.

Dr. Taylor said its important that the guidelines home in on the people who can most benefit from treatment. He also noted that blood pressure guidelines can end up hurting people if they wrongly label someone as being at risk.

Maybe those people should be focusing on conditions other than their borderline blood pressure, Dr. Taylor said. If we intervene with these people who dont have a lot of risk, maybe were going to cause more harm than benefit.

Dr. Aram V. Chobanian, president emeritus of Boston University, who was chairman of the 2003 guidelines panel, said those recommendations were based on studies showing that the risk of heart disease starts to rise at readings as low as 115/75.

Dr. Chobanian said he had not read the latest study, which looked at mortality risk rather than heart disease risk, but noted that other doctors have raised concerns about a designation of prehypertension for people with blood pressure of 120/80.

Some physicians feel its an overemphasis, and I understand that, he said. If you identify individuals who are candidates for prevention of hypertension, that to me is the greatest point of it, to pick out people whom you want to make  or try to make them  change their lifestyle.

Dr. Taylor noted that a single study is not likely to change the guidelines, but he hopes the research will be included in the discussion of blood pressure guidelines. The eighth Joint National Committee panel is currently reviewing the guidelines and is expected to make draft recommendations later this year.


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## imfree (Mar 10, 2011)

The older I get and the more I learn about the way the human body works, the less value I see in the numbers. Weight, BP, blood sugar, and many other parameters, affect people's health at levels that vary by individual. I have a sneaking suspicion that a person's mental state even affects how the body reacts to all these parameters. BTW, don't have your BP checked if you're pissed at anything or have anxiety over a known doctard.


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## Miss Vickie (Mar 10, 2011)

We recently did a module in my pharmacology class on hypertension and the lecturer said he's far more concerned about the potential for endothelial and end organ damage than what the actual systolic number is. He looks at the aspects of metabolic syndrome: hyperlipidemia (especially high triglycerides and low HDL), hyperinsulinemia, visceral adiposity, and hypertension too, but hypertension as part of the larger syndrome. If you have metabolic syndrome you have a much higher risk of a cardiac event (I believe it's 8x). 

From my prior understanding of hypertension, the concern is not only shortening lifespan, but also the affect on the kidneys, eyes, and heart (left ventricular remodeling). So you may not die young but you'll live a long time with a LOT of health problems -- diabetes, congestive heart failure, kidney disease, things that are NO fun.

I'm really glad to see that they're looking more closely at insulin. They used to solely look at fasting glucose which is kind of only showing you one small piece of the picture. If it takes a ton of insulin to keep your glucose normal, you're burning out your pancreas and putting your body at risk from all the problems which stem from too much insulin like inflammation, visceral weight gain, and endothelial damage which set you up for atherosclerosis. Getting insulin under control improves cardiac function. Go figure!

One of the updates they shared with us was a new recommendation that slightly higher blood pressures were acceptable for elderly folks. I suspect that this is maybe because they have a tendency toward having postural hypotension since their baroreceptors are a little sluggish and many have problems with fainting and falling. Keeping their pressures a little higher no doubt keeps more blood going to their brains and preserves consciousness. It could also be that their response to medications tends to be less predictable and more profound.


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## Tad (Mar 10, 2011)

One thing that always puzzled me, regarding blood pressure and so many other biological markers, is why the classifications of good and bad numbers always seem to be based on just the number, not drift in the numbers? I deal with reliability in electronics, and when the readings are marginal, the concern is always 'is that a stable number, or is it drifting? And if it is drifting, how quickly?'

For example my mother is in that pre-hypertension zone and age 72....and has been since at least age 18 (the first time her blood pressure was measured, when she was training as a lab tech and they practiced on each other). I would think that should be of less concern than someone who long had 'normal' blood pressure, but who has recently moved to having those somewhat high readings?

Maybe it is just too complicated to track and classify all of that?


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## Miss Vickie (Mar 10, 2011)

Tad, in order to diagnose someone with hypertension they have to have more than one reading that's elevated on more than one occasion (I believe it's three different elevated readings on three different occasions. I'd look it up but all my books are in my car, ready for my trip out to a coffee shop to do some studying). As we age, our blood pressure naturally elevates because our vessels have less elasticity; that doesn't mean it's "healthy" but rather it's something that's an expected part of aging.

The drifting thing (if I understand you right, the comparison over time) is done during pregnancy when diagnosing preeclampsia. A woman with a normal blood pressure of 120/80 could be diagnosed as preeclamptic if she had protein in her urine and her blood pressure is elevated from her first prenatal visit. So in that case, drifting is significant because it's a sign of disease. But they don't really look at other people that way, because the issue is really the effect the high pressure has on the vessels and organs, which can be devastating and permanent.

Hope this helps?


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