What is High Blood Pressure – When and How Should it Be Treated?

What is High Blood Pressure – When and How Should it Be Treated?

High blood pressure, medically known as hypertension, is a very common cardiovascular condition where the long-term force of blood against your artery walls is consistently too high.

Over time, this sustained pressure can damage your blood vessels and significantly increase your risk of serious health conditions; including heart disease, heart attacks, heart failure, chronic kidney disease (CKD) and strokes.

Often referred to as a ‘silent killer,’ hypertension affects approximately 1 in 3 adults in the UK. Because it rarely presents obvious warning signs, understanding how to identify, monitor, and manage your blood pressure is essential for long-term health.

Understanding Blood Pressure Readings

Blood pressure is measured in millimetres of mercury (mmHg) and is recorded as two distinct numbers; written as one ‘over’ the other (e.g. ‘127/83’ mmHg):

• Systolic Blood Pressure (Top Number): Measures the pressure in your arteries when your heart beats and pumps blood out.

• Diastolic Blood Pressure (Bottom Number): Measures the pressure in your arteries when your heart rests between beats.

What is ‘Normal’ Blood Pressure

There is no such thing as normal blood pressure.

There is a normal range, usually taken to be approximately 90/60 – 135/85.

What is normal depends on many factors including:

• Age – normal BP rises with age, so:
  • 120/70 can be normal in your 20s-30s
  • 130/80 in 40s-60s
  • 140/90 in 70s+
  • 150/95 in 80s+
  • Note ‘pulse pressure’ (difference between systolic and diastolic) also increases as you age
• Gender – men have higher blood pressures, so there should be a lower threshold to treat a woman in middle/later life with ‘borderline BP’.
• If female – pregnant/not (BP goes down in pregnancy).

High-Risk Groups and Contributing Factors

While anyone can develop high blood pressure, certain demographic and lifestyle factors significantly elevate your risk:

• Age: The risk of developing hypertension increases naturally as blood vessels lose elasticity with age.

• Family history: Of hypertension, and its complications and treatment

• Ethnicity: Black and Asian people are more prone to developing high blood pressure and experiencing its complications at an earlier stage.

• Lifestyle Factors: Diets high in sodium (salt), a lack of regular physical activity, being overweight or obese, smoking, and high alcohol consumption are major contributing risks.

• Medical Factors: Diabetes, Medication – e.g. steroids, CNI inhibitors, oestrogen-containing products (OCP, HRT etc).

Primary and Secondary Causes of Hypertension

Hypertension is generally classified into two types based on its underlying cause:

1. Primary (Essential) Hypertension

This form accounts for roughly 90% of all diagnosed cases. It develops gradually over many years with no single, identifiable medical cause.

Instead, it is typically the result of a combination of genetic predisposition, age-related vascular changes, and lifestyle factors.

2. Secondary Hypertension

This type (the other 10%) is caused by an underlying medical condition or external factor. Common causes of secondary hypertension include:

• Chronic Kidney Disease (CKD)

• Diabetes

• Other endocrine (hormonal) disorders (such as thyroid problems or adrenal gland tumours)

• Cardiac (heart) causes (such as coarctation of the aorta, and aortic regurgitation (very wide pulse pressure)

• Obstructive Sleep Apnoea (OSA)

• Certain medications (including NSAIDs, oral contraceptives, HRT, and corticosteroids)

• Pregnancy, where sudden high blood pressure can indicate pre-eclampsia or eclampsia

Hypertension Symptoms

The vast majority of people with high blood pressure experience no symptoms at all. However, if blood pressure reaches dangerously high levels (especially if it arises from a secondary cause), some individuals may experience:

• Frequent early morning headaches

• Blurred vision, blood spots in the eyes, or visual disturbances

• Shortness of breath or chest pain

• Noticeable heart palpitations

Note: If you experience these symptoms alongside elevated blood pressure readings, consult a doctor immediately.

How is High Blood Pressure Diagnosed?

A single high reading does not mean you have chronic hypertension. Blood pressure fluctuates throughout the day due to its natural (‘circadian’) rhythm, stress, caffeine, and anxiety.

As the problem is silent in most people, to confirm a diagnosis, doctors may organise:

• Ambulatory Blood Pressure Monitoring (ABPM): Regarded as the ‘gold standard’ for diagnosis. A wearable device measures your blood pressure at regular intervals over a 24-hour period during your normal daily routine.

• Home Blood Pressure Monitoring (HBPM): Tracking readings at home helps rule out ‘white coat syndrome’—a phenomenon where blood pressure spikes temporarily due to the anxiety of being in a medical clinic or hospital. See below for advice on how to carry out HBPM.

• Common Diagnostic Tests: Blood tests (e.g. kidney function, HBA1c, cholesterol); urine analysis; and an electrocardiogram (ECG) and chest x-ray (CXR) – check for causes of high BP, and early signs of organ damage.

• Specialist Blood Tests and Scans: These may be needed if rarer causes of secondary hypertension are a suspected.

Hypertension Stages – and When It Should Treated

Doctors categorise blood pressure readings into distinct stages to determine the necessary level of medical intervention.

The decision to treat depends on your age, gender, cardiovascular risk, and dangers of over-treatment (see below).

But for most people, this is true.

Note. Thresholds for BP treatment are affected by age. For example BP in range 135/85 to 140/90 should be treated in a younger patient (middle/later life).

When Should High BP Not Be Treated?

• When the risks of treatment outweigh the benefits. For example, in an 80 year old with dementia and falls, the risk of low blood pressure causing a fall (leading to an operation for a fractured neck of femur) outweighs benefits of treatment.
• Based on one or a small number of readings.

What are the risks of low blood pressure?

Low. Most people in middle/later life will not notice blood pressure running low (e.g. 90/50 – 100/60). It will also carry little risk. Medication can be altered at the next routine assessment, if needed.

But. Older/frailer (>80 years) people will notice low blood pressure and feel dizzy, especially on standing from a chair or bed. If this is the case, the risk of falls (and their complications) is significant. Medication should be reduced, or even stopped – then reassessed at a later date.

Lifestyle Management and Prevention Strategies

The primary goal of managing hypertension is to lower blood pressure into a safe range, thereby minimising the risk of cardiovascular events. Initial management often focuses on clinical lifestyle intervention:

• Sodium Reduction: Restrict your salt intake to less than 6 grams per day (approximately one teaspoon; a normal West diet contains 8-8.5 grams a day) by avoiding processed foods, and not adding extra salt to cooking or on food when served..

• Dietary Adjustments: Adopt dietary patterns like the DASH diet (Dietary Approaches to Stop Hypertension), which emphasises whole grains, fruit, vegetables, lean protein, and low-fat dairy (cheese, milk, yoghurt etc).

• Regular Exercise: Aim for at least 150 minutes of moderate-intensity aerobic exercise (such as brisk walking, cycling, or swimming) per week.

• Weight Management: Achieving and maintaining a healthy weight significantly reduces strain on the cardiovascular system.

Note. Actual human salt need is alot less than in a Western diet. It is 0.5-1.25 grams per day. This small amount is enough to conduct nerve impulses, balance body fluids, and maintain muscle function.

How Should High Blood Pressure be Treated?

When lifestyle modifications alone are insufficient, doctors prescribe antihypertensive medications based on clinical evidence and individual patient profiles:

• ACE Inhibitors and ARBs: (e.g. Ramipril and Losartan) These relax blood vessels and are often the first choice for younger patients.

• Calcium Channel Blockers: (e.g. Amlodipine) These prevent calcium from entering the muscle cells of the heart and blood vessels, allowing them to relax. They are often preferred for patients over 55 years or individuals of African or Caribbean heritage.

• Diuretics: (e.g. Indapamide and Bendroflumethiazide) These help the kidneys flush excess water and sodium from the body, reducing total blood volume.

• Beta-Blockers and Alpha-Blockers: (e.g. Bisoprolol, Doxazosin) These are alternative options used to lower heart rate or relax specific vascular muscles when primary therapies need support.

• Other More Specialist/Stronger Drugs: Methyldopa, Labetolol (both used in pregnancy), Moxonidine; Hydralazine, Minoxidil (both should be prescribed by hospital blood pressure specialist doctors).

Which drugs should be used in which people (and in what order)?

It depends – on age, gender (pregnant/not) and ethnicity. These factors are incorporated into the 4-Step NICE BP treatment guidelines.

Should any medication be stopped?

Again, it depends – on the need for that medication. For example, steroids or CNIs (used to prevent organ transplantation) should not be stopped.

But stopping oestrogen containing medication should be considered (e.g. OCP, HRT). Part of that decision is lifestyle – e.g. if a post-menopausal woman benefits from HRT (in terms of symptoms), she may prefer to continue HRT and add BP medication to ‘allow’ that.

Checking compliance with lifestyle changes and medication

Long-term compliance with both adjustments is very variable. So compliance is worth checking. How?

Lifstyle changes – check (and record) weight, assess salt intake using ‘spot’ urinary sodium measurement

Medication – diuretics (blood Na/K levels, and urinary sodium), betablockers (pulse rate should fall), and urinary antihypertensive agent metabolites.

Complications of Untreated Hypertension (Why High BP Should be Treated)

Leaving high blood pressure unmanaged places continuous, destructive stress on your arterial walls and vital organs.

This chronic strain can lead to serious, life-threatening complications, including:

• Cardiovascular Events: Increased risk of myocardial infarction (heart attack) and hypertensive heart failure; stroke and transient ischaemic attack (TIA or mini-stroke).

• Organ Damage: Chronic Kidney Disease (CKD) or Acute Kidney Injury (AKI) due to damaged renal blood vessels.

• Vision Impairment: Hypertensive retinopathy, which can lead to permanent vision loss.

• Vascular Emergencies: Accelerated hypertension (also called hypertensive emergency) and, in rare cases, aortic dissection.

Note 1. Mild-Moderarte Primary/Essential hypertension does not cause CKD or AKI. Accelerated hypertension can.

Note 2. One of the most important reasons to treat high BP is to prevent non-fatal strokes.

Best Practices for Home Blood Pressure Monitoring

For those tracking their blood pressure at home, consistency and proper technique are vital to obtaining accurate, reliable data:

• Ensure Equipment Fits: Use a validated home blood pressure monitor. Ensure the arm cuff is the correct size for your arm circumference; a cuff that is too small can artificially inflate your reading.

• Prepare Correctly: Same time of day. Sit quietly for 5 minutes before taking a reading. Sit upright in a chair with your back supported, feet flat on the floor, and your arm resting at heart level. Avoid caffeine, exercise, and smoking for 30 minutes prior to testing.

• Use the Rule of Three: Take three consecutive readings, spaced about one to two minutes apart. Discard the first reading (as it is often elevated due to initial anxiety) and record the average of the final two readings.

  • Four Days in a Row: You will often be asked to take your BP 3 times a day (say 8am and 6pm) for 4 consecutive days and show them to your doctor. For most people in middle/later life, readings should be under 135/85 most of the time.

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