Monitoring blood pressure: the silent killer

Monitoring blood pressure: the silent killer
Medical Matters

Have you had your blood pressure checked recently? Well, measurement of blood pressure, as we all know, is a fundamental part of the routine clinical examination – and for good reason.

This is because high blood pressure or hypertension is for the most past a silent condition which, over time, may have far-reaching health consequences. To some extent, an elevated blood pressure may be considered a normal part of ageing.

While below 40 hypertension is uncommon, by middle age prevalence increases to up to 50% and further rises to approximately 75% in those over 65.

The importance of getting your blood pressure checked is emphasised by the fact that in up to half of cases hypertension is undiagnosed. The reasons underlying hypertension are complex and not fully understood but involve changes in resistance to blood flow in our arteries.

This is mediated by dysfunction in the inner lining of the arteries that produce vaso-active chemicals that narrow their calibre.


The effects of high blood pressure are manifold. It significantly accelerates atherosclerosis or hardening of the arteries, a process whereby they become internally coated with plaque and narrowed.

This can cause damage to the arteries anywhere in the body including in the heart, kidneys, eyes, legs and brain, and can lead to coronary artery disease, kidney impairment, visual problems and poor circulation.

Hypertension is also a major risk factor for stroke and puts strain on the heart which can lead to impaired heart muscle function and heart failure. Damage due to hypertension can also result in further elevation of blood pressure.

In the past, high blood pressure was often not diagnosed until later in life (by which time it may have caused organ damage) or was only picked up incidentally. We know however, that diagnosis and treatment of hypertension even later in life will substantially reduce the risk of cardiovascular disease and events.

Diagnosis should be made on the basis of at least two elevated blood pressure readings at two different times”

In fact, hypertension is one of the most important causes of premature morbidity and mortality.

If other risk factors including high cholesterol, diabetes or smoking are present, there is a ‘snowball effect’ whereby the risk increases exponentially. This is why a diagnosis of hypertension should always prompt a complete assessment for other vascular risk factors.

Diagnosis should be made on the basis of at least two elevated blood pressure readings at two different times. If elevated, a 24-hour ambulatory blood pressure monitor may be considered to accurately confirm the diagnosis, particularly if there is a concern regarding ‘white coat hypertension’.

While there are no natural cut-offs for blood pressure, there are well defined treatment targets and even a small drop in blood pressure can significantly reduce the risk of stroke and heart disease. If you have diabetes, heart disease or end organ damage then a tighter control of your blood pressure will be recommended.


Factors that contribute to hypertension such as being overweight, smoking and taking alcohol in excess should be addressed. While not all cases of hypertension are ‘salt sensitive’, most studies show that reducing salt intake (if high) can also modestly lower blood pressure.

Regular exercise has also been shown to have a positive effect. Evidence also suggests that having a healthy diet may lower blood pressure and of course will help in optimising other vascular risk factors such as high cholesterol.

If you have mild hypertension, paying attention to the above factors may remove the need to go on anti-hypertensive medication.

However, in practice at some stage during the course of your hypertension you are likely to require medical treatment. For many with high blood pressure two or more tablets will be required.

Several medications are available to choose from and which one is used will depend on how high the blood pressure is, the presence of other conditions like diabetes or kidney/heart disease and the potential for side effects. Treatments are very effective and usually well tolerated.

If you have not had your blood pressure checked for some time, I strongly advise you to do so!”

If blood pressure is difficult to control, resistant to treatment or unusually high at a young age, then you should be checked out for specific medical causes of hypertension. These account for about 5-10% of all cases and include certain kidney and endocrine disorders.

In summary, high blood pressure is common and rarely gives rise to any symptoms. However, it is a ‘silent killer’ and needs to be checked and monitored closely. If you have not had your blood pressure checked for some time, I strongly advise you to do so!

Dr Kevin McCarroll is a Consultant Physician in Geriatric Medicine, St James’ Hospital, Dublin.