what is a healthy blood pressure reading?

healthy blood pressure

Could “Raised” Blood Pressure Not Be The Danger We Have Been Told?

We have all had it drummed into us that increased blood pressure (BP) can lead to heart attack and stroke, and that it is something to be avoided at all costs. Hence the need for anyone with even moderately raised BP to consider taking BP lowering medication to regain a healthy blood pressure level.  When advised to do so by your GP, who wholeheartedly (excuse the pun) believes this to be good for your heart and your health, and will cite you all sorts of studies confirming this belief, it will be very difficult for most people to resist this advice – after all doctor knows best, right?

Well, maybe not, unless he or she has the time to check up on studies that present other findings and can form their own opinion, as opposed to embracing the opinion and dogma of medical associations worldwide without question, which is usually the case for time poor GPs.

In the course of my usual research, I came across the excellent Dr. Malcolm Kendrick, a Scottish doctor, who has written the fascinating book “Doctoring Data,” which will give you a huge insight into and an ability to read between the lines of any medical study results that you ever encounter. It is witty, funny and full of useful information you are not likely to encounter anywhere else. In the course of future blogs, I shall probably draw on some of the fascinating things he has revealed, but for the moment, what really impressed me was a 2000 study written by a statistician and two cardiologists from the University of California, Los Angeles. In general this study completely refutes the accepted “science” that lowering BP results in lower mortality from cardiovascular disease as one ages (although it is true in the case of very high BP).

The accepted model is known as “the linear relationship between mortality and blood pressure,” and emerged from the findings of the Framingham Study, which began in 1948, and still continues, studying participants, and descendants, from the town of Framingham, Massachusetts in the US. The linear model simply means that for each increase in BP reading there is a corresponding straight line increase in mortality risk. Sounds logical, even reasonable, and this concept has become enshrined in medical teachings and dogma. In a 1991 study Jeremiah Stamler MD further cemented this concept with his quote

“the relation of SBP [systolic blood pressure] to risk of death is continuous, graded, and strong, and there is no evidence of a threshold ,”

Pretty conclusive, no? But this paradigm and all of the ACE inhibitor BP lowering drugs that are prescribed every day to combat this linear danger, are all based on the results from the Framingham Study. What if this seminal study data had been misinterpreted? What would that mean for the current medical paradigm and dogma on BP, not to mention the billions of dollars, or is that trillions by now, that have been made by pharmaceutical companies on the back of the massive sales of these BP lowering drugs?

This is why the 2000 study, “There is a non-linear relationship between mortality and blood pressure,” really caught my attention. It is only 4 pages long and well worth a read. You can download it here. In it the study authors reviewed the data from Framingham and, being careful only to include those years of data that were not impacted by the now widespread use of ACE inhibitors which would have skewed the results, came to the conclusion the paradigm is false! They wrote,

“Shockingly, we have found that the Framingham data in no way supported the current paradigm to which they gave birth. In fact, these data actually statistically rejected the linear model. This fact has major consequences. Statistical theory now tells us that the paradigm MUST be false for the target population of the study (white, urban middle class Americans ages 45–74),” (“must” in bold was used by the authors).

So the paradigm is false. This is pretty shocking stuff and you would have thought that this study should have caused a lot of heated debate, but so well entrenched is the paradigm that it seems nothing can shake it, and this study received seemingly little attention although published in the European Heart Journal. The authors went on to say,

“Systolic blood pressure [the higher number on a BP reading] increases at a constant rate with age. In sharp contrast to the current paradigm, we find that this increase does not incur additional risk. More specifically, all persons in the lower 70% of pressures for their age and sex have equivalent risk. However, risk rapidly increases with pressure for those in the upper 20% of pressures for their age and sex.”

The study sets out the following new model as a more logical way of evaluating the risks associated with increasing BP as we age.

  1. There is an age and sex dependent background risk that is independent of systolic blood pressure (current paradigm believes the lower the pressure the better – this new model says there is a constant background risk up to 150 mmHg systolic pressure see figure below).
  2. In contrast to current thinking, there is an age and sex dependent threshold and risk only increases steadily with pressures that exceed that threshold.
  3. The threshold keeps pace with the increase in pressure with age. It always can be taken to be the 70th percentile of systolic blood pressure for a person of a given age and sex.
  4. Their formula to calculate this threshold
    • for a man aged 45-74 is        110+(2/3)x(age) and
    • for a woman aged 45–74 is   104+(5/6)x(age).
  5. Although the point at which the increase in risk begins depends on age and sex, the relative risks for pressures above threshold are the same for all ages and both sexes.

new model of blood pressure

This figure from the study represents the new model (horizontal line then sharper upward curve) versus the linear model, for ages 56–64. The shaded area represents the individuals (about 30% of this population) who may be inappropriately treated by the present criterion which regards 140mmHg as the threshold to start treatment.

On this much more logical basis, that due to natural increasing BP with age the threshold at which risk starts also increases with age, we would see far fewer people prescribed BP lowering medication. In addition armed with the rule of thumb calculations above, you can very quickly see if your systolic BP has crossed the threshold into increased risk territory.

Being on medication makes sense if it is actually doing you some good and reducing mortality risk, although our outlook at CoolWellbeing is that there is often a perfectly natural way of achieving the same result if one is prepared to make lifestyle changes and add certain supplements into one’s daily regimen. But we can see no point or benefit in being on medication when it is not called for because there is no increased mortality risk to attempt to combat.

We would suggest downloading and printing out the short study from the link above to keep for future reference and showing it to your doctor if he or she is ever insistent on prescribing you BP lowering meds.

In case you think this 2000 study is too old and that surely there must be something more recent that would confirm its findings, just stop to consider that it would have been impossible for several decades now to construct a randomised controlled trial of BP lowering drugs versus no treatment since the belief in lowering BP at all costs is so strong that it would be considered unethical and medical malpractice not to give someone medication if it is considered that they are hypertensive. So ethics approval would never be granted for such a trial. That is why the data from the Framingham Study is of such huge value because it comes from an era when BP lowering drugs did not exist, so researchers can use it to see what mortality risk factors really did exist as blood pressure increased as the participants aged.

Thankfully, there are researchers out there who are not afraid to kill the sacred cow!!

Stay happy and for a healthy blood pressure maintain your BP well below the safe threshold for your age and sex using the calculations given above.

The Team at CoolWellbeing Foundation

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