最後更新日期 十一月 19, 2021.
Hypertension, or high blood pressure, is a serious medical condition that increases the risk of heart, brain, kidney, and other diseases. In Hong Kong, 1 in 10 people has hypertension; however, half of those with hypertension are usually unaware of their condition, as hypertension could be asymptomatic. Wonder how hypertension is diagnosed? What are the normal blood pressure ranges? How is hypertension treated? Find out the answers through our guide to hypertension.🩸
Hypertension Meaning: What is Hypertension?
Hypertension means high blood pressure. Blood pressure is the pressure exerted on blood vessel walls as the heart pumps. Normal blood pressure is required to push blood through the body so that oxygen and nutrients can reach all tissues. Blood pressure can rise and fall depending on heart function, blood vessel health, and many other reasons. It fluctuates throughout the day and is influenced by emotions and physical activity. For example, blood pressure increases with anger or anxiety and drops during rest or sleep.
Normally, an adult should have a systolic blood pressure below 120 mmHg and a diastolic pressure below 80 mmHg (also written as 120/80mmHg). Hypertension refers to a persistent elevation in systolic blood pressure of 140 mmHg or above or diastolic blood pressure of 90 mmHg or higher (written as >140/90mmHg).
Patients with hypertension can be asymptomatic. As there are usually no symptoms of high blood pressure, regular blood pressure measurement is required to detect blood pressure abnormalities and treat them as soon as possible before any complications arise. Adults are recommended to check for their blood pressure at least once a year, while elderly over 75 should visit the doctor and measure their blood pressure at least twice a year.
Causes and Risk Factors of Hypertension
Hypertension can be classified into primary (essential) hypertension or secondary hypertension depending on their causes.
Primary Hypertension (Essential Hypertension)
Around 95% of hypertension are primary. The exact causes of primary hypertension are usually unknown, but certain risk factors can increase the chance of developing high blood pressure, including:
- Family history: If any of your parents are hypertensive, your risk of developing hypertension doubles.
- Ethnicity: Hypertension is more common in people of African descent.
- Age: Blood vessels become stiffer and blood pressure increases with age.
- Overweight and Obesity: The heart works harder to pump blood through the body, which puts strain on your arteries, leading to an increase in blood pressure.
- High sodium diet: Consuming over 3 grams of salt per day can significantly increase your chance of hypertension.
- Alcohol: Alcohol is a highway to hypertension. Having more than 2 drinks per day can significantly induce a higher risk of hypertension.
- Smoking cigarettes or vaping: Chemicals in smoking products can damage the lining of blood vessels, causing blood vessels to narrow and increase blood pressure.
- Lack of exercise: If you are physically inactive, your blood pressure rises more readily with the less efficient heart and blood vessels.
- Stress and anxiety: Poor mental health can change the body’s hormonal levels, which may alter blood pressure.
Secondary hypertension is caused by underlying health conditions or medications. Risk factors of primary hypertension contribute to the severity of secondary hypertension as well. Health conditions that cause secondary hypertension include:
- Renal diseases, such as chronic kidney diseases, glomerulonephritis (damage to the tiny filters inside kidneys) or renal artery stenosis (narrowing of arteries supplying the kidney), etc.
- Diabetes: Consistently high blood glucose can lead to hardening of arteries, a condition called atherosclerosis, which causes hypertension.
- Obstructive sleep apnoea: The walls of the throat relax and narrow during sleep, interrupting normal breathing.
- Hormone problems, such as hypothyroidism, hyperthyroidism, Cushing’s syndrome, aldosterone or adrenaline-producing tumours.
- Systemic lupus erythematosus (SLE): An autoimmune disease in which the immune system attacks its own body.
- Medicines that induces blood pressure raise may include:
– Oral contraceptives
– Non-steroidal anti-inflammatory drugs (NSAIDs)
– Some ingredients in cough and cold preparations, such as Phenylephrine or Pseudoephedrine
– Recreational drugs, such as Cocaine and Amphetamines
Hypertension: High Blood Pressure Symptoms and Signs
The majority of hypertensive patients show no symptoms. Hypertension is usually discovered during a routine check-up or until complications arise.
Even if hypertension presents signs and symptoms, they are usually not specific and do not appear until the high blood pressure has reached a severe or life-threatening level. People with extremely high blood pressure may experience these symptoms and require immediate medical attention:
- Lightheadedness or dizziness
- Visual disturbance
- Facial flushing
- Nose bleed
- Difficulty breathing
- A pounding feeling in the head
- A pounding feeling in the chest (Palpitation)
- Nausea and vomiting
Complications of Hypertension
If hypertension is not regulated well, serious complications may occur. Common complications of hypertension include:
- Atherosclerosis: Hypertension is a leading cause of atherosclerosis, in which arteries are narrowed and hardened. Atherosclerosis can result in heart attack, stroke and shock.
- Stroke: Hypertension may either reduce blood supply to the brain leading to a rapid loss of brain function by ischaemic stroke, or damage the brain vessels causing hemorrhagic stroke.
- Heart attack or heart failure: Hypertension causes the heart to pump against high blood pressure, making it work harder than necessary. Cardiac muscles thicken and restrict blood flow which leads to heart failure over time.
- Hypertensive retinopathy: High blood pressure can damage blood vessels in the optical retina, resulting in vision damage or even vision loss.
- Osteoporosis: Hypertension may increase the amount of calcium excretion in urine. Excessive loss of calcium may lead to insufficient absorption of calcium and loss of bone density.
- Kidney failure: Prolonged high blood pressure can damage the small tubules within the kidney, leading to nephron damage and kidney failure.
What is a Normal Blood Pressure Range?
Blood pressure is generally measured in millimeters of mercury (mmHg). It is classified into systolic blood pressure and diastolic blood pressure:
- Systolic blood pressure (SBP) represents the pressure in the blood vessels when the heart contracts to pump blood.
- Diastolic blood pressure (DBP) represents the pressure in the blood vessels when the heart relaxes between heartbeats.
Blood pressure levels can be categorized as follows:
Systolic blood pressure
Diastolic blood pressure
Normal blood pressure
< 120 mmHg
< 80 mmHg
120 - 139 mmHg
80 - 89 mmHg
> 140 mmHg
> 90 mmHg
Grade 1 Hypertension
140 - 159 mmHg
90 - 99 mmHg
Grade 2 Hypertension
160 - 179 mmHg
100 - 109 mmHg
Grade 3 Hypertension
> 180 mmHg
> 110 mmHg
There are multiple guidelines that define hypertension ranges slightly differently. In Hong Kong, physicians generally refer to 140/90 mmHg as the boundary for hypertension. However, some physicians may apply stricter guidelines and diagnose a patient as hypertensive if the blood pressure is over 130/80 mmHg constantly depending on individual conditions.
Most people do not know their blood pressure until regular body checks. Prehypertension is a state before hypertension and indicates a high risk of high blood pressure development. Steps should be taken to improve your health and regulate blood pressure when prehypertension is reached.
Note that an occasional increase in blood pressure above the normal blood pressure range may not indicate hypertension, such a rise can be a normal physiological response due to stress or other conditions. If hypertension is suspected, seek medical advice immediately and consult your physician on available lifestyle changes and treatment options.
How to Measure the Blood Pressure
Blood pressure is measured using a sphygmomanometer, also known as a blood pressure monitor. There are a few types of different sphygmomanometers, among which the manual and digital meters are most commonly used by physicians and the public respectively. Doctors may ask hypertensive patients to record their blood pressure at regular time periods daily by themselves.
Steps to measure the blood pressure yourself by a digital meter
- Before measuring blood pressure, do not eat, drink caffeinated beverages, smoke and exercise 30 minutes before the measurement. Stay at a quiet place and relax for 5 to 10 minutes without any distractions before taking the blood pressure. Wear loose-fitting and comfortable clothes, sit back straight on a comfortable chair, put your feet on the floor without crossing, keep calm and relax while measuring your blood pressure.
- The blood pressure monitor comes with a cuff, fastened the cuff onto your upper arm 2.5 cm proximal to your elbow wrinkle. Make sure to elevate your arm on a cushion to the same level as your heart before starting the measurement.
- By turning on the digital sphygmomanometer, the cuff will inflate and tighten for a few seconds and then deflate and loosen to measure your blood pressure. Relax throughout the whole process to avoid any undesirable changes in blood pressure.
- Record the systolic blood pressure, diastolic blood pressure and heart rate shown on the reading of the digital meter.
- The measurement process should take a minute or so. Remove the cuff and repeat Step 1-4 after a few minutes’ break (at least 1 minute). Take the average values of the 2 measurements as your final blood pressure of the day.
- If there are any inaccuracies (such as a 5mmHg difference between the 2 measurements), you may take another measurement again after a few minutes’ break (at least 1 minute). However, be reminded that blood pressure recorded after 3 consecutive measurements are considered less accurate. Relax and measure the blood pressure sometimes a lot later in the day in this case. Do not be stressed if you fail to record accurate measurements occasionally, the recording of blood pressure is meant to be a monitor rather than a mental burden.
Diagnosis of Hypertension
High blood pressure is mainly diagnosed by blood pressure measurements by physicians. If your physician measures a record of blood pressure that is over 120/80 mmHg continuously (prehypertension) or is 140/80 mmHg or above consistently (hypertension), the physician will diagnose you hypertensive.
When such high blood pressure is recorded, your doctor may also measure your heart rate, calculate your BMI, perform physical examinations and other tests to confirm the diagnosis and check for any underlying causes of hypertension.
- Ambulatory monitoring: Your blood pressure is monitored over 24 hours to confirm the diagnosis of hypertension. It also shows blood pressure changes throughout the day.
- Laboratory test: You may need a urinalysis (urine test), blood test and cholesterol test to check for potential complications.
- Electrocardiogram (ECG or EKG): Your heart’s electrical activity can reflect the conditions of your heart and indicates any cardiovascular complications.
- Echocardiogram: Sound waves are used to produce images of the heart in order to look for any signs of heart disease.
- Fundoscopy: If you experience vision problems, your doctor may inspect the internal eyes to check for any damages to the retina and optic nerve.
Treatments for Hypertension
Patients with hypertension are advised to make healthy lifestyle modifications. You should keep in mind the following to monitor and lower your blood pressure:
- Routine blood pressure measurement: Routine self-monitor of your blood pressure at home is the most essential measure for treating hypertension. You may obtain a reliable digital blood pressure monitor at your doctor’s recommended locations, pharmacies, medical supply stores or electronic stores. Follow the previously mentioned steps to measure your blood pressure at home.
- Do more exercise: Doctors often recommend exercise goals as well, which usually consist of aerobic physical activities, resistance exercises and stretching exercises. Aim for at least 30 minutes of moderate physical activity every day, such as a brisk walk, jogging or swimming.
- Maintain a healthy weight or lose weight if you are overweight or obese. Aim for a BMI that falls within the normal range.
- Reduce salt intake to less than 6 grams per day.
- Eat a balanced diet that is low-fat, rich in fresh fruits and vegetables.
- Drink less caffeine found in coffee, tea and cola.
- Avoid alcohol
- Quit smoking: Check out our guide to smoking cessation.
If hypertension remains consistent after carrying out the above lifestyle modifications, the risk of developing complications is higher. Doctors may prescribe the following antihypertensive agents along with advice on lifestyle changes to regulate your high blood pressure:
- ACE inhibitors or Angiotensin-2 receptor blockers (ARB), such as Captopril, Lisinopril, or Losartan. They work by primarily relaxing narrowed blood vessels and decreasing sodium retention in the kidneys.
- Calcium channel blockers (CCB), such as Nifedipine, Felodipine and Diltiazem. They reduce cardiac muscle contraction to reduce cardiac output and relax the blood vessels to lower resistance within the blood vessels.
- Thiazide diuretics, such as Hydrochlorothiazide or Indapamide. They promote urination to eliminate water and sodium to lower blood volume, thereby reducing blood pressure.
- Beta-blockers, such as Atenolol or Propranolol. They lower blood pressure by reducing heart rate.
Although you may not experience any symptoms of high blood pressure, you must take the prescribed medications. This is very important to prevent those fatal complications of hypertension from developing. The management of hypertension highly depends on your commitment to combating high blood pressure. Be proactive in self-management and adopt healthy lifestyle practices, take your antihypertensive drugs on time, record your blood pressure regularly, attend medical check-ups on a regular basis to treat hypertension properly.
Preventative Measures for Hypertension
Adopting a healthy lifestyle is the most fundamental in preventing hypertension, such habits to prevent hypertension can be summarized as follows:
- A healthy life shouldn’t be too salty! Reduce your sodium intake by avoiding high-salt foods such as smoked, pickled, or preserved foods. A healthy adult should consume no more than 2 grams of sodium (1 teaspoon of salt) per day. Check the sodium content of prepackaged foods by their nutrition labels. Herbs, spices or lemon juice can be used to replace salt and MSG in cooking.
- Eat a well-balanced diet that is rich in fruit and vegetables, as well as appropriate amounts of whole grain products, fish, nuts, lean meat, and low-fat dairy products. Do not consume foods high in salt, sugar or oil.
- Exercise more: Aim to exercise at least 30 minutes per day. Adults should do at least 150 minutes of moderate-intensity physical activity or 75 minutes of vigorous-intensity physical activity weekly. If you have been inactive, start with simple exercises and gradually increase the intensity. If you definitely hate exercising, check out these easy-peasy workouts! If you are a techie, here are the best free fitness apps for you!
- Avoid prolonged sitting. Do you know sitting too much has the same health effect as smoking? Set an alarm to get up every 30 minutes from sitting.
- Stay in shape. Maintaining your body weight and waistline is important for cardiovascular health. For Asian adults, aim to maintain a BMI between 18.5 – 22.9, and waist circumference below 90 cm (36 in) for men and 80 cm (32 in) for women.
- Stop smoking. Quitting smoking greatly reduces cardiovascular risk. Second-hand smoke also increases your risk of developing heart disease. Stop smoking and encourage your close ones to quit smoking now.
- Limit alcohol consumption. No hangover, no fun? If you are a heavy drinker, try to keep it to a minimum amount which means up to 1 drink per day for women and 2 drinks per day for men.
- Stay positive and mentally healthy! Stress and mental illness increase blood pressure readily. Exercise, yoga, Tai Chi and deep breathing are all great ways to cope with stress. Have stressful work? Check this guide for more tips. If you are stressed or depressed, don’t hesitate to seek help from family, friends or healthcare professionals.
- Ensure enough sleep and rest. Healthy adults should sleep 7 – 9 hours daily, while children need to sleep longer. Learn how to cope with your Circadian rhythm.
If you or your loved one is suffering from hypertension, you may get more help from the following organizations:
- Primary Healthcare Office (Food and Health Bureau) – Hypertension Care Advice
- GovHK – Exercise and Nutrition Advice
- Shall We Talk