Hypertension

What it is

Hypertension is persistently high blood pressure, commonly defined as 140/90 mmHg or higher on repeated measurements. The most important fact is that WHO estimates 1.4 billion adults aged 30 to 79 years were living with hypertension worldwide in 2024, and many do not know they have it. Blood pressure is recorded as two numbers: systolic pressure, when the heart contracts, over diastolic pressure, when the heart relaxes between beats.

Hypertension is often called a “silent” condition because most people have no symptoms until complications develop. Over time, uncontrolled high blood pressure damages blood vessels and increases the risk of stroke, heart attack, heart failure, chronic kidney disease, and some forms of dementia. In most adults, the cause is primary (essential) hypertension, meaning there is no single identifiable cause. A smaller group has secondary hypertension, which is linked to another condition such as kidney disease, endocrine disorders, or certain medicines.

A simple way to think about it is:

Type	What it means
Primary (essential) hypertension	High blood pressure without one specific reversible cause; most common type
Secondary hypertension	High blood pressure due to another condition, such as kidney disease, sleep apnea, or hormone disorders
Hypertensive crisis	Very high blood pressure, often around 180/120 mmHg or higher, needing urgent assessment

In India, hypertension is a major noncommunicable disease problem and is increasingly seen in both urban and rural populations, partly related to high sodium intake, low physical activity, obesity, diabetes, and population aging.

How it works

Blood pressure reflects how hard blood pushes against artery walls. It depends mainly on two things: how much blood the heart pumps and how much resistance there is in the arteries. Hypertension develops when blood vessels become stiffer or narrower, the kidneys retain too much sodium and water, or hormone systems that regulate blood pressure become overactive.

Several body systems are involved:

1. Blood vessels: Arteries can become less elastic and more constricted.
2. Kidneys: The kidneys help control salt, water balance, and blood pressure. Kidney disease can both cause and result from hypertension.
3. Hormones and nerves: The renin-angiotensin-aldosterone system and sympathetic nervous system can raise blood pressure when overactive.
4. Lifestyle factors: High salt intake, excess body weight, alcohol, tobacco, poor sleep, and inactivity all contribute.

This ongoing pressure injures the lining of blood vessels. Over years, that damage promotes atherosclerosis and strains organs that depend on healthy circulation, especially the brain, heart, kidneys, and eyes.

Diagnosis / how it's measured

Hypertension is diagnosed by repeated blood pressure measurements, not by a single high reading. WHO notes that diagnosis is made if blood pressure measured on two different days shows systolic pressure of 140 mmHg or higher and/or diastolic pressure of 90 mmHg or higher. Some professional societies, especially in the United States, use a lower threshold of 130/80 mmHg for defining hypertension, which is why readers may see different cutoffs in different sources.

Common measurement methods include:

Method	Why it matters
Clinic measurement	Standard first step, but can be affected by stress or technique
Home blood pressure monitoring	Helps detect persistent hypertension and track treatment response
Ambulatory blood pressure monitoring	Measures BP over 24 hours; useful for white-coat or masked hypertension

Doctors also look for target-organ damage and possible secondary causes. Evaluation may include:

• medical history and family history
• weight, waist size, and physical examination
• blood tests for kidney function, glucose, and lipids
• urine testing for protein
• ECG, and sometimes echocardiography
• review of medicines such as NSAIDs, steroids, oral contraceptives, and decongestants

Because technique matters, blood pressure should ideally be measured after sitting quietly for several minutes, with the correct cuff size and the arm supported at heart level.

Evidence and uses

The main goal of treating hypertension is to reduce the risk of cardiovascular and kidney complications. Evidence from large clinical trials shows that lowering blood pressure reduces the risk of stroke, heart failure, heart attack, and death from cardiovascular causes.

Treatment usually combines lifestyle measures and, when needed, medicines.

Key lifestyle measures include:

• reducing sodium intake
• eating more fruits, vegetables, pulses, and whole grains
• maintaining a healthy weight
• regular physical activity
• limiting alcohol
• stopping tobacco use
• improving sleep and treating sleep apnea when present

In India, lowering salt intake is especially relevant because many diets include substantial sodium from pickles, papads, packaged snacks, instant foods, and restaurant meals. Home-cooked food is not automatically low in salt.

Common medicine classes include:

Drug class	Examples
ACE inhibitors	Enalapril, ramipril
ARBs	Losartan, telmisartan
Calcium channel blockers	Amlodipine
Thiazide or thiazide-like diuretics	Hydrochlorothiazide, chlorthalidone
Beta blockers	Atenolol, metoprolol; often used for selected indications rather than all patients

Many people need more than one medicine to reach target blood pressure. Treatment targets vary by age, frailty, diabetes, kidney disease, and the guideline being followed, but many clinicians aim for around 130/80 mmHg or lower when it is safe and tolerated.

When to see a clinician

See a clinician if repeated home or clinic readings are high, even if you feel well. Hypertension often causes no symptoms, so waiting for headaches or dizziness is not reliable.

Seek urgent care right away if blood pressure is around 180/120 mmHg or higher, especially with symptoms such as:

• chest pain
• shortness of breath
• severe headache
• confusion
• weakness or trouble speaking
• vision changes
• severe nausea or vomiting

You should also seek medical review if you are pregnant, have diabetes, kidney disease, prior stroke, or are taking medicines that may raise blood pressure.

Limitations and open questions

Not all blood pressure thresholds are identical across guidelines. WHO uses 140/90 mmHg for diagnosis in many settings, while some U.S. guidance uses 130/80 mmHg. This can confuse patients, but the broader point is consistent: higher long-term blood pressure raises risk.

Another limitation is measurement itself. Clinic readings can be misleading because of white-coat hypertension or masked hypertension, so home or ambulatory monitoring is often helpful.

There are also open questions about the best treatment targets for very old adults, people with multiple illnesses, and some ethnic populations. Evidence strongly supports treatment overall, but the ideal target should be individualized. Research continues on how best to improve awareness, adherence, and blood pressure control at the population level, especially in low- and middle-income countries where the burden is high.