High blood pressure

What blood pressure is and what the numbers mean

Blood pressure is a measurement of the pressure at which blood flows through your blood vessels. Each time the heart beats it pumps blood through a network of vessels that carry oxygen and nutrients around the body, and that blood exerts a force against the walls of the arteries as it travels.

Two numbers are recorded during a blood pressure measurement, a systolic reading and a diastolic reading, and both are recorded in millimetres of mercury, written as mmHg. The systolic reading is the force with which your heart pumps blood under pressure, during systole. The diastolic reading is taken when the heart is at rest and measures the resistance to blood flow in the vessels between heartbeats.

Those two numbers are written together, systolic over diastolic, which is where the familiar readings come from.

Blood pressure usually rises with age because the arteries stiffen, and other conditions such as diabetes and hypercholesterolaemia affect the blood vessels in their own right. The threshold used for older patients is not the same as the one used for everyone else.

• Around 120/80mmHg sits inside the normal range, which the British Heart Foundation puts at 90/60mmHg to 130/85mmHg
• Between 130/85mmHg and 139/89mmHg is what the British Heart Foundation calls pre-hypertension, raised but not yet diagnosed as high blood pressure
• 140/90mmHg or higher when checked by a healthcare professional is classed as hypertension
• Below 150/90mmHg in clinic, or below 145/85mmHg at home, is the target usually applied to people over 80
• Below 90/60mmHg is hypotension, or low blood pressure

What sustained high blood pressure does to the heart

When the pressure inside the arteries stays too high, the vessels are under constant strain. Over time that elevated pressure damages the lining of the arteries, making them less flexible and more vulnerable to narrowing or blockage. It also weakens the vessel walls, adding strain that can eventually lead to a rupture.

The heart itself has to work harder. Imagine a pump trying to push water through a pipe that is under constant pressure, where the pump has to exert more force to maintain the flow. The heart works in much the same way, and over time that extra workload can cause the heart muscle to thicken. Thickening may initially help the heart cope with the increased demand, but it eventually makes the heart less efficient.

Sustained hypertension, meaning prolonged periods of high blood pressure, could put you at risk of other serious health conditions. These could include the following.

Long standing high blood pressure is also one of the common underlying causes of heart failure, and of cardiomyopathy, where the heart muscle itself becomes diseased. Controlling blood pressure is therefore one of the most effective ways to protect the heart and reduce the risk of serious complications later in life.

• Heart disease
• Heart attacks
• Strokes
• Heart failure
• Peripheral artery disease (PAD)
• Aortic aneurysms
• Kidney failure
• Vascular dementia and other brain injuries

The symptoms people notice

Most people with high blood pressure experience no symptoms at all, which is why it is often discovered during a routine medical check. Unlike conditions that cause immediate discomfort, hypertension may not produce any clear signs until damage has already begun.

In more severe cases you may notice symptoms such as the following.

These symptoms can occur for many reasons and do not always indicate hypertension. They should still be evaluated if they persist. The most reliable way to detect elevated blood pressure remains regular monitoring rather than waiting for something to feel wrong.

• Headaches
• Dizziness
• Shortness of breath
• Blurred vision

What makes high blood pressure more likely

Several factors contribute to the development of high blood pressure. Some are related to lifestyle habits, while others involve genetics or ageing.

Common risk factors include the following.

Age plays a role as well, since blood vessels naturally become less flexible over time. Sleep matters more than most people expect. During healthy sleep, blood pressure naturally falls overnight and gives the cardiovascular system time to recover, and when sleep is poor or interrupted it may remain elevated for longer periods.

There are some things you cannot control that contribute to higher blood pressure levels, such as your ethnic background and your socioeconomic status. The NHS lists a Black African, Black Caribbean or South Asian background among the things that raise your risk, and high blood pressure is more common in more deprived areas. Even when genetic or age related factors are present, lifestyle adjustments can still have a meaningful impact.

• Family history of hypertension
• High salt intake
• Excess body weight
• Physical inactivity
• Chronic stress
• Excessive alcohol consumption

How high blood pressure is diagnosed

Diagnosing high blood pressure involves measuring it on more than one occasion. A single elevated reading does not always confirm hypertension, because blood pressure fluctuates throughout the day, and stress, physical activity and even caffeine intake can temporarily influence a reading.

For this reason several measurements are usually taken over time, or home monitoring is recommended. You may also be asked to wear an ambulatory blood pressure monitor, a device worn for 24 hours that records measurements throughout the day and night and calculates an average reading. That gives a more complete picture of how the body regulates pressure than a single reading taken on one occasion.

A home blood pressure monitor is a worthwhile investment if you do not already have one. Blood pressure is considered high at 135/85mmHg or higher when measured at home, so most adults aim below that, though your own target may be different depending on other conditions you have.

Blood pressure is rarely assessed on its own. A thorough cardiovascular assessment includes a proper history and examination, blood pressure, blood tests such as a lipid panel and HbA1c, an ECG, and where indicated an echocardiogram to look at the structure and function of the heart muscle. Accurate assessment allows treatment to be tailored to the individual.

How high blood pressure is treated

Treatment for high blood pressure starts with lifestyle changes to diet and exercise. One of the more encouraging aspects of treating hypertension is that small changes can make a meaningful difference.

Measures that help to reduce and manage your blood pressure include the following.

If lifestyle changes do not make enough difference, medication can be given to help control blood pressure levels. Different medicines work for different people, and the first medicine tried is not always the most suitable one. The choice will depend on age, ethnicity and average overall blood pressure levels, and medication is normally used alongside lifestyle changes rather than replacing them.

High blood pressure usually develops gradually, which means improvement tends to happen gradually too. Patients often expect dramatic changes to be necessary, when in reality the most powerful improvements come from sustainable routines that become part of everyday life, supported by regular monitoring and a plan that suits your own situation.

• Increasing your level of exercise, since even 20 minutes of activity each day can support healthy blood pressure levels
• Losing weight
• Reducing salt intake and prioritising whole foods, with many people benefiting from a Mediterranean diet built around vegetables, fruits, whole grains and healthy fats such as olive oil
• Reducing stress, which can raise blood pressure and encourage habits such as poor sleep or overeating
• Avoiding coffee or alcohol
• Prioritising consistent, good quality sleep

When to seek help

High blood pressure is usually silent, so the reason to seek help is more often a number than a symptom. If a reading has come back high, if hypertension runs in your family, or if headaches, dizziness, shortness of breath or blurred vision persist, it is worth being assessed properly rather than waiting to see what happens.

A cardiology review is also worthwhile if your blood pressure stays stubbornly high despite lifestyle changes, or if you have chest discomfort on exertion, unexplained breathlessness, palpitations, dizziness, blackouts, or a noticeable drop in your exercise tolerance.

Call 999 immediately if you or someone with you has chest pain, collapses, or shows signs of a stroke. A stroke is a serious, life threatening condition that requires immediate and urgent treatment to minimise the damage to the brain.

For anything that is not an emergency, an assessment with Dr Jogiya can establish whether your blood pressure is genuinely raised, usually through repeated measurement over 24 hours, and may include blood tests, an ECG and, where the structure of the heart needs to be assessed, an echocardiogram. This page is general information about high blood pressure and is not individual medical advice.