What is Hypertension?

Blood pressure is the pressure exerted on blood vessels during contraction and relaxation of the heart. This pressure is usually described in terms of millimeters of mercury (mmHg). The pressure recorded during contraction of the heart is called "systolic blood pressure" (SBP), and the pressure recorded during relaxation of the heart is called "diastolic blood pressure" (DBP).

Hypertension is a condition in which the SBP is persistently higher than or equal to 140 mmHg, or DBP is persistently higher than or equal to 90 mmHg.

Situation in Hong Kong

Hypertension is common in Hong Kong. The Population Health Survey 2020-22 revealed that the total prevalence of hypertension was 29.5% among persons aged 15-84, including self-reported doctor-diagnosed hypertension and no self-reported history but raised blood pressure by physical measurement. The prevalence of hypertension increases with age, from 4.9% for people aged 15-24 to 57.4% for people aged 65-84.

Causes of hypertension

  • Great majority, 90% of hypertension has no definite cause and is called "primary hypertension". The risk factors described below may be related to the disease
  • 10% of hypertension is secondary to other diseases, such as renal diseases and endocrine disease

Risk Factors for hypertension

  • Smoking
  • Overweight & obesity
  • Physical inactivity
  • High salt intake
  • Excessive alcohol intake
  • Ageing
  • Family history (first degree relative) of hypertension

Symptoms of Hypertension

  • The majority of patients have no symptoms. The condition is usually discovered during a routine check up or when complications develop
  • Extremely high blood pressure may cause symptoms like dizziness, visual disturbance, headache, facial flushing and fatigue


Untreated or uncontrolled hypertension can lead to complications like heart failure, coronary heart disease, stroke, renal failure, etc. Uncontrolled hypertension is a silent killer. Early diagnosis and proper treatment can effectively prevent or delay the complications.

Regular blood pressure monitoring

Most patients with hypertension have no obvious symptoms. Adults are advised to have regular blood pressure measurement.1

Blood pressure categories Blood pressure (mmHg) Recommendations
Systolic Diastolic
Optimal Lower than 120 Lower than 80 Recheck in 2 years
(Once a year for people aged over 75)
Normal 120-129 80-84 Recheck in 1 year
High normal 130-139 85-89 Recheck in 6 months
Hypertension Higher than or equal to 140 Higher than or equal to 90 Consult your family doctor as soon as possible for advice
1Doctor may modify review period according to reliable information about past blood pressure measurements, other cardiovascular risk factors, or target organ diseases.

After obtaining the patient's medical history and performing a detailed physical examination, the doctor will arrange other investigations if required, such as blood tests, urine tests, electrocardiogram, chest X-ray examination and fundus examination to find out causes and complications of hypertension.

Management of Hypertension

The management of hypertension depends on the commitment of the patient to participate proactively in self-management and adopting healthy lifestyle practices:

  • Take medication according to doctor’s prescription and attend regular medical follow-up
  • Self-monitoring of blood pressure
  • Maintain a healthy lifestyle
  • Stop smoking
  • Maintain optimal body weight and waist circumference (BMI <23 kg/m2, waist circumference <90 cm for men, waist circumference <80cm for women)
  • Adopt a healthy eating habit. Reduce salt intake and eat more fruits and vegetables
  • Perform moderate-intensity aerobic physical activity in bouts of at least 10 minutes, such as jogging, walking, practising Tai Chi, swimming., to reach the weekly target of at least 150 minutes in total or 75 minutes vigorous intensity aerobic physical activity in total (if you have risk factors for cardiovascular disease, please seek medical advice before exercise.)
  • Avoid alcohol
  • Manage stress properly and stay positive

For more information on hypertension, please visit the websites "Hong Kong Reference Framework for Hypertension Care for Adults in Primary Care Settings 【Patient Version】" & "Hong Kong Reference Framework for Preventive Care for Older Adults in Primary Care Settings"(Traditional Chinese version only) or consult your family doctor.