23 May 2019
Measuring blood pressure is one of the basic tests taken during a physical examination. Photo: Reuters
Measuring blood pressure is one of the basic tests taken during a physical examination. Photo: Reuters

How to measure blood pressure accurately

Measuring blood pressure is one of the basic tests taken during physical examinations or visits to medical clinics.

In the medical profession, 140/90 mmHg or above indicates high blood pressure. However, the American Heart Association recently updated the definition of high blood pressure, tightening it to 130/80 mmHg or above.

In other words, more people now fall within the range of high blood pressure. It may be a good thing from a different perspective.

Hypertension is said to be one of the “global invisible killers”, and patients usually have no obvious symptoms. It is also common among the elderly, who usually only experience dizziness and headache, which are often overlooked or mistaken as the symptoms of cold and flu.

Nevertheless, high blood pressure will cause other severe chronic diseases such as heart disease and stroke.

Although it is still unclear whether Hong Kong will follow the new guidelines, the purpose of tightening the guidelines is not just to “diagnose” more patients, but to alert some people who are on the edge of having hypertension.

It is hoped that they will try to lower their blood pressure through non-medical treatment, such as changing their lifestyle.

For many patients, hypertension is a mere index. That is a wrong view.

By definition, blood pressure is the pressure generated in the artery when blood is delivered from the heart.

Systolic pressure refers to the pressure caused by the arteries when the heart contracts, while diastolic pressure refers to the pressure in the arteries when the heart rests between beats.

If either one of the pressure numbers is higher than the normal range, that’s hypertension. The patient should see a doctor and seek medical treatment as soon as possible.

A sphygmomanometer, or also known as a blood pressure meter, is the most common tool to measure blood pressure at home or in clinics.

Blood pressure numbers can be affected by walking up and down the stairs, nervousness, just waking up in the morning and many other reasons.

If a doctor finds that the patient’s blood pressure is often high but the blood pressure at home is normal, the doctor might advise the patient to carry out 24-hour ambulatory blood pressure monitoring.

This automatically measures blood pressure every half hour during the day and every hour at night to obtain more accurate blood pressure data.

If necessary, the doctor will arrange further tests such as blood tests and electrocardiogram to detect the cause of high blood pressure in order to prescribe appropriate medication.

With or without high blood pressure, people should maintain good living habits, such as reducing salt intake, smoking cessation, weight control and regular exercise.

These are the best ways to prevent high blood pressure and improve one’s condition.

This article appeared in the Hong Kong Economic Journal on Jan 2

Translation by John Chui

[Chinese version 中文版]

– Contact us at [email protected]


Registered cardiologist, FHKAM (Medicine)

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