Around one in three adults in the UK has high blood pressure. The majority of them have no idea. That is not because they are careless — it is because hypertension produces no symptoms whatsoever until something goes seriously wrong. This article explains what high blood pressure is, why it matters, and what you can do about it.

What is blood pressure, and what do the numbers mean?

Blood pressure is the force your blood exerts against the walls of your arteries as your heart pumps. It is measured in millimetres of mercury (mmHg) and expressed as two numbers — for example, 130/85 mmHg.

Systolic pressure (the top number) is the pressure when your heart beats and pumps blood out.
Diastolic pressure (the bottom number) is the pressure when your heart rests between beats.

A reading below 120/80 is considered optimal. Between 120/80 and 140/90 is an elevated or high-normal range — worth monitoring. A reading consistently at or above 140/90 mmHg is diagnosed as hypertension and warrants treatment or close management.

It is worth noting that blood pressure fluctuates throughout the day and in response to stress, activity, caffeine, and other factors. A single high reading is not always cause for immediate alarm — but consistently elevated readings are.

Why high blood pressure is so dangerous

The heart and blood vessels are designed to operate within a certain pressure range. When that pressure is persistently elevated, the consequences accumulate silently over years:

Heart attack and heart disease. High pressure forces the heart to work harder, thickening and stiffening the heart muscle over time and accelerating atherosclerosis — the build-up of fatty plaques in arterial walls.
Stroke. Hypertension is the single biggest risk factor for stroke, both through vessel damage and through the risk of aneurysm formation.
Kidney disease. The kidneys are extremely sensitive to blood pressure; chronic hypertension damages the delicate filtering vessels and is one of the leading causes of chronic kidney disease.
Vascular dementia. Damage to small blood vessels in the brain, driven by hypertension over years, is closely linked to cognitive decline.
Eye damage. Hypertensive retinopathy — damage to the blood vessels in the retina — can impair vision and, in severe cases, cause blindness.

None of these consequences is inevitable. But they are far more likely to develop in someone whose blood pressure has been elevated and untreated for years — which is exactly what happens when hypertension goes undetected.

Who is at risk?

Certain factors significantly raise the likelihood of developing high blood pressure:

Age. Blood pressure tends to rise with age as arteries become stiffer. The majority of people over 65 have hypertension.
Family history. Hypertension runs strongly in families. If a parent or sibling has it, your own risk is meaningfully elevated.
Ethnicity. People of Black African and Black Caribbean heritage have higher rates of hypertension and are more likely to develop it at a younger age.
Being overweight. Excess body weight — particularly abdominal fat — increases the strain on the cardiovascular system and promotes hormonal changes that raise blood pressure.
High salt intake. The kidneys regulate blood pressure partly through sodium balance. High dietary sodium leads the body to retain more fluid, increasing vascular pressure.
Excessive alcohol consumption. Regular heavy drinking raises blood pressure directly, and alcohol interacts with many antihypertensive medications.
Physical inactivity and chronic stress. Both raise baseline blood pressure and contribute to cardiovascular risk more broadly.

The problem with waiting for symptoms

This is the core difficulty with hypertension: it genuinely has no symptoms until it is severe or has already caused damage. People do not feel their blood pressure rising. Headaches, which many associate with high blood pressure, are not a reliable indicator — most headaches occur in people with perfectly normal blood pressure, and most people with significantly elevated blood pressure feel entirely well.

This means the only way to know your blood pressure is to measure it. And yet many adults in the UK go years — sometimes decades — between checks. A significant proportion of people whose blood pressure would warrant treatment have never been told they have a problem.

What to do if your blood pressure is high

If a reading comes back elevated, the approach depends on how high it is and what other risk factors are present:

Lifestyle changes are the foundation of treatment for most people with stage 1 hypertension (140–159/90–99 mmHg). Reducing salt, increasing physical activity, limiting alcohol, losing weight if appropriate, and managing stress can all produce meaningful reductions in blood pressure — sometimes enough to bring it into a normal range without medication.
Medication is recommended when blood pressure is consistently above 160/100 mmHg, or when it is above 140/90 with other cardiovascular risk factors present. There are several effective antihypertensive drug classes — ACE inhibitors, calcium channel blockers, ARBs, and thiazide diuretics — and finding the right one or combination is a straightforward clinical process. Most people tolerate blood pressure medication well.
Monitoring and follow-up are essential. Blood pressure management is not a one-time event — it requires regular review to assess how well readings are controlled and adjust treatment as needed.

Getting checked

Blood pressure measurement is one of the simplest and most valuable health checks available. It takes two minutes. Our health screening service includes blood pressure assessment as part of all our screening packages, alongside blood tests, cardiovascular risk profiling, and a clinical review. If you have a specific concern, our same-day GP service can check your blood pressure, investigate if necessary, and advise on next steps promptly.

The investment of two minutes could genuinely save your life — and this is not hyperbole. Treated hypertension substantially reduces the risk of heart attack and stroke. The catch is that treatment requires detection first.

High blood pressure: the silent condition most people don't know they have