Sunday, June 4, 2023

Controversies in Medicine: When Is Blood Pressure Considered High?

There is controversy, but no conspiracy, in how high blood pressure is defined.


Medical organisations consider readings above 140/90, 135/85, 130/85 and 130/80 mmHg as high blood pressure (BP). So depending on the doctor you go to, your high BP treatment may change.

The Science

In 2017, the American Heart Association (AHA) and the American College of Cardiology (ACC) reduced the cut-off for high BP to 130/80 mmHg.

  • With this lower cut-off, millions of people who were said to have ‘normal’ BP became labelled as high BP patients, raising their numbers by forty per cent in one go.
  • Conspiracy theorists claimed that this cut-off lowering was incentivised by pharmaceutical companies so that they could sell medicines to more people.
  • A more significant controversy arose when the American Academy of Family Physicians (AAFP) refused to accept the new guidelines.
  • AAFP stuck to 140/90 mmHg and further said that they would increase the cut-off to 150/90 mmHg from 140/90 mmHg for people above 60 years of age. AHA strongly opposed such easing.

What is the High BP Cut-off Today?

  • Cardiologists in the USA (AHA/ACC): 130/80 mmHg
  • Cardiologists in South America (LASH): 130/85 mmHg
  • Family Physicians in the USA (AAFP): 135/85 mmHg to prevent heart attacks; 140/90 mmHg to prevent deaths
  • Cardiologists in Europe (ESH): 140/90 mmHg
  • Cardiologists in the rest of the world (ISH): 140/90 mmHg


There is no conspiracy in this. Over the years, the definition of high BP has changed:

  • In the 1910s, high blood pressure (hypertension) was considered desirable. Science thought high BP was the body’s healthy way of pushing blood through clogged arteries.
  • In the 1950s, medicine realised that high BP was not beneficial.
  • In the 1960s, doctors understood that lowering BP was helpful.
  • In the 1970s, science considered 180 mmHg as not significant. Today, that would be regarded as a ‘hypertensive crisis’ needing an urgent doctor visit.
  • In the early 1980s, 150 to 180 mmHg was considered ‘mild’ hypertension.
  • In the 2000s, 140/90 mmHg was the cut-off for high BP.

AHA and ACC (American Cardiologists) drafted their guidelines after new studies showed that lowering BP to 130/80 mmHg prevented significantly more heart attacks and deaths.

“When the facts change, I change my mind. What do you do, sir?”

—John Maynard Keynes, Economist and Philosopher

Unfortunately, those trials also showed increased side effects such as fainting, dizziness, and fatigue, which AAFP felt were not worth the extra risk for some reduction in heart attacks and deaths.

Family physicians control a patient’s overall health; safeguarding only the heart is not their priority. Cardiologists, in contrast, prefer a focused high BP treatment. So both sides are faultless in their views.

When different groups of cardiologists disagree on the cut-off levels for defining high BP, treatment decisions become more complicated. But that is how medical science progresses: first by disagreement and then by consensus.

To Read More

First Published on: 21st May 2023
Image Credit: Image by Freepik


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