High Blood Pressure
Hypertension
High blood pressure, also known as Hypertension, is a very common and serious condition where the pressure inside the arteries is consistently too high.
It is often called a ‘silent killer’ because most people don’t experience any obvious symptoms, and if left undetected and uncontrolled, it can lead to serious health problems.
UPDATED: 15 December 2025
What is blood pressure?
Before exploring hypertension and its effects in more detail, let’s first review what we mean by blood pressure.
Briefly, there are two main phases to each heartbeat:
Systole - As the heart contracts (squeezes), blood is pumped out of the heart, increasing pressure within the arteries, reaching a peak pressure called Systolic Blood Pressure.
Diastole - After contracting, the heart relaxes, refilling with blood to pump again during the next heartbeat. During this time, the blood pressure in the arteries drops back to its resting level, called Diastolic Blood Pressure.
The walls of our arteries are highly elastic, made up of layers of elastic fibres. Their design allows them to expand and contract with the changes in pressure associated with blood flow, ensuring a constant, smooth delivery of oxygen and nutrients to smaller blood vessels within your brain, organs, muscles, and tissues.
As we age, these elastic fibres can become less flexible, reducing their ability to expand. This process leads to a gradual increase in Systolic and Diastolic Blood Pressure.
How can High Blood Pressure develop?
Blood flow through an artery - notice how the artery expands and contracts during systole and diastole.
Aside from the natural aging process, if the blood pressure in your arteries becomes elevated due to certain diet, lifestyle, or medical reasons and remains at this higher pressure, it can cause damage along the inside of the artery walls.
The injured tissue swells, and healing substances such as white blood cells collect around the damaged areas to promote healing. Fat and cholesterol traveling within the blood may also attach to these swollen injury sites, slowly building up a fatty plaque. This plaque thickens and hardens the inner surface of the artery, a condition called Atherosclerosis, restricting blood flow and increasing blood pressure, which puts a greater strain on your heart.
This creates a feedback loop none of us wants, where elevated blood pressure damages arteries, accelerating atherosclerosis, which in turn increases blood pressure further!
Build up of plaque within the artery wall narrows the blood vessel, which restricts blood flow and forces the heart to work harder, leading to high blood pressure.
Killer Consequences of Hypertension
Atherosclerosis can have dangerous consequences. If a fatty plaque bursts open, a blood clot forms on top of the rupture site, further obstructing blood flow. And if the clot becomes large enough, it can completely block the flow of blood, leading to killer consequences.
Heart Attack – A blockage within the arteries supplying blood to the heart muscle (coronary arteries) will cause a heart attack, as the heart muscle is starved of oxygen and slowly starts to die.
Stroke – If a blood clot cuts off the blood supply to a part of the brain, brain cells become damaged due to a lack of oxygen and begin to die. This is called an ischaemic stroke and can lead to brain injury, disability, or possibly death.
Blood pressure measurement
When your blood pressure is measured, two numbers are provided, appearing like a fraction (e.g., 120/80mmHg). The top number is your Systolic blood pressure, and the bottom is your Diastolic blood pressure, given in the unit of measure mmHg (millimetres of mercury).
It is important to know that a person’s blood pressure changes throughout the day, much like heart rate changes in response to activity levels and feelings of stress. With this in mind, we usually only refer to blood pressure readings measured at rest.
Measure blood pressure at home
Regularly measuring your blood pressure at home is easy and important to check to see if it is within the normal range, or for those on treatment for hypertension to check their medication is working.
Current medical guidelines support the use of home blood pressure monitoring as it has been proven to provide a more accurate measure of a person’s true blood pressure at rest.1,2,3,4 Ultimately, the best place to measure will be wherever you feel most relaxed.
Both the European and UK guidelines agree that a normal blood pressure measured at home and at rest is less than 135/85mmHg.2,3,4 Whereas the US guidelines recommend a lower threshold of less than 130/80mmHg, with the caveat to assess each person individually.5
Important
If you are concerned about your blood pressure, please consult with your doctor.
If your blood pressure is 180/120mmHg, please seek urgent medical help
Home blood pressure monitors
Tracking your blood pressure at home and recording a history gives you real-time insight and helps you spot trends long before symptoms appear. Home monitoring also gives your doctor a much clearer picture of your health compared to a one-off reading when you see them. This can be as simple as a handwritten log, or if your monitor connects to a mobile app, each blood pressure reading can be synced to a smartphone or tablet. These readings can then be emailed to your doctor when requested.
Modern home-monitoring technology can simplify this task, but choosing which blood pressure monitor to buy is not so simple, especially when you see hundreds of different options available to buy online.
For advice on buying a home blood pressure monitor, click below
Prepare – Avoid smoking, drinking caffeine/alcohol, taking medications, or exercising 30 minutes before measuring.
Rest and relax for at least 5 minutes before measuring blood pressure.
Sit still with your back supported, feet flat on the floor, legs uncrossed, and your arm resting on the table.
Use an appropriately sized cuff in the correct position (2cm above the elbow joint on the left arm). Remove clothing covering the location of cuff placement, i.e., roll up the sleeve.
Take three measurements at 1-minute intervals and use the average of the last two (avoid talking during measurements). Record the results in a notebook or with a mobile app.
How to measure blood pressure at home
When initially checking your blood pressure at home or following an elevated reading obtained at the doctor’s surgery/health centre, it’s a good idea to:
Measure and record your blood pressure twice daily (using an average as mentioned in step 5 above), both in the morning and evening, for ideally 7 days.
Discard the measurements from the first day and calculate the average of the remaining days. This will help guide you and your doctor.
For advice on buying a home blood pressure monitor, click below.
Important Information:
This page is provided for general educational purposes only and does not constitute medical advice. Medical knowledge and guidance evolve over time, and information may change. Always seek advice from a qualified healthcare professional regarding personal health concerns or medical decisions.
For more details, please see our full Disclaimer.
References
1. M, Stergiou GS, Tomaszewski M, Wainford RD, Williams B, Schutte AE. 2020 International Society of Hypertension Global Hypertension Practice Guidelines. Hypertension. 2020 75(6):1334-1357.
2. Williams B, Mancia G, Spiering W, Agabiti Rosei E, Azizi M, Burnier M, Clement DL, Coca A, de Simone G, Dominiczak A, Kahan T, Mahfoud F, Redon J, Ruilope L, Zanchetti A, Kerins M, Kjeldsen SE, Kreutz R, Laurent S, Lip GYH, McManus R, Narkiewicz K, Ruschitzka F, Schmieder RE, Shlyakhto E, Tsioufis C, Aboyans V, Desormais I; ESC Scientific Document Group. 2018 ESC/ESH Guidelines for the management of arterial hypertension. Eur Heart J. 2018 1;39(33):3021-3104.
3. Stergiou GS, Palatini P, Parati G, O'Brien E, Januszewicz A, Lurbe E, Persu A, Mancia G, Kreutz R; European Society of Hypertension Council and the European Society of Hypertension Working Group on Blood Pressure Monitoring and Cardiovascular Variability. 2021 European Society of Hypertension practice guidelines for office and out-of-office blood pressure measurement. J Hypertens. 2021 Mar 11.
4. Jones NR, McCormack T, Constanti M, McManus RJ. Diagnosis and management of hypertension in adults: NICE guideline update 2019.
5. Whelton PK, Carey RM, Aronow WS, Casey DE Jr, Collins KJ, Dennison Himmelfarb C, DePalma SM, Gidding S, Jamerson KA, Jones DW, MacLaughlin EJ, Muntner P, Ovbiagele B, Smith SC Jr, Spencer CC, Stafford RS, Taler SJ, Thomas RJ, Williams KA Sr, Williamson JD, Wright JT Jr. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Hypertension. 2018 71(6):e13-e115.