What Is Prehypertension

Prehypertension, or high normal blood pressure, is diagnosed when your blood pressure numbers are consistently above the optimal level of 120/80 mmHg but below the 140/90 mmHg level needed to diagnose high blood pressure, or hypertension.

Prehypertension numbers

Prehypertension, or high normal blood pressure, is defined as having a blood pressure that is consistently between 120/80 mmHg and 139/89 mmHg.

Only one of your blood pressure readings needs to be in this range to diagnose prehypertension, so if your systolic blood pressure (upper number) is between 120 mmHg and 139 mmHg, or if your diastolic blood pressure (lower number) is between 80 mmHg and 89 mmHg you have prehypertension (or high normal blood pressure).

You can check how your blood pressure ranks using the following chart. Find your systolic pressure (top number) on the left of the chart, and your diastolic pressure (bottom number) across the bottom of the chart. The colour will show if either reading is low, ideal or within the pre-hypertension or hypertension range. If your systolic and diastolic blood pressures fall into different categories the higher classification is used.

You can print off this chart using the link at the bottom of the page.

One-off readings are not used to diagnose prehypertension as your blood pressure will likely increase when it is being measured in the clinic due to the stress effects of White Coat Hypertension.

Your blood pressure will be checked several times to see if it comes back down into the normal range.

How common is prehypertension?

Prehypertension is at least as common as hypertension, with at least a third of adults affected.

The insidious rise in blood pressure has become so common that some researchers have described it as the prehypertension tsunami.

Why is prehypertension bad?

There is growing recognition that people whose blood pressure falls within the prehypertension or high normal range are highly likely to progress to full-blown hypertension. You also have an increased risk of developing circulatory complications than if your blood pressure stayed in the normal range.

One study followed 204 ‘healthy’ people with prehypertension for up to 20 years, or until their first cardiovascular event occurred. More than two out of five went on to develop hypertension that needed treatment.

Around one in 8 experienced a circulatory event such as needing a coronary artery revascularisation,  fatal or non-fatal heart attack, heart failure, fatal or non-fatal stroke, or developed an abdominal aortic aneurysm.

One third of those who developed these serious complications were within the prehypertension range at the time.

Prehypertension and stroke

Worldwide, at least 54% of strokes are attributable to high blood pressure.

People with prehypertension also have a higher risk of stroke than if their blood pressure were below 120/80 mmHg.

The results from 19 studies, involving 762,393 people, show that, after adjusting for all other cardiovascular risk factors, having prehypertension is associated with a 66% increased risk for stroke, compared with having an optimal blood pressure of less than 120/80 mm Hg.

If your blood pressure is in the LOW end of the prehypertension range (systolic 120 mmHg to 129 mmHg, and/or diastolic 80 mmHg to 84 mmHg) you have a 44% increased risk of stroke compared with having a normal blood pressure.

If your blood pressure is in the HIGH end of the prehypertension range (systolic 130 mmHg to 139 mmHg, and/or diastolic 85 mmHg to 89 mmHg) you have a 95% increased risk of stroke compared with having a normal blood pressure.

Prehypertension and kidney disease

Having a higher than optimal blood pressure damages the tiny filtering units within the kidneys. Research involving 261,264 people aged from 20 to 89 years, who were followed for up to 11 years found that people with prehypertension were 28% more likely to develop chronic kidney disease than those with optimal blood pressure.

Prehypertension treatment

If you are told you have prehypertension, or high normal blood pressure, your doctor will advise you that diet and lifestyle changes can bring it down into the normal blood pressure range. Drug treatment is not prescribed unless your blood pressure creeps up into the hypertension range.

Having a diagnosis of prehypertension is an important health crossroads. It shows that your blood pressure is increasing due to a combination of factors such as your age, diet, lifestyle, weight, and the genes you have inherited, which all contribute to the cause of prehypertension.

Making a few simple changes will help bring your blood pressure down without the need for medication.

That’s what this blood pressure site is all about.

Monitor your blood pressure

When you have prehypertension, it is important to monitor your blood pressure regularly, to ensure your diet and lifestyle changes are bringing it down, and that you are not creeping up into the hypertension range.



Self-monitoring is key to help stop your prehypertension progressing to hypertension.

Click here for advice on choosing a blood pressure monitor to use at home.

See my recommended upper arm blood pressure monitors.

Image credits: maxpixel; monkey_business/shutterstock; 


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