What Is High Blood Pressure?
Blood pressure is the force exerted by blood against the walls of your arteries as your heart pumps. Hypertension — persistently elevated blood pressure — is one of the most common and serious health conditions globally. It's often called the "silent killer" because it typically causes no noticeable symptoms, yet steadily damages blood vessels, the heart, kidneys, and brain over time.
Blood pressure is measured in millimetres of mercury (mmHg) and expressed as two numbers: systolic (pressure when the heart beats) over diastolic (pressure when the heart rests between beats).
Understanding Blood Pressure Readings
| Category | Systolic (mmHg) | Diastolic (mmHg) |
|---|---|---|
| Optimal | Below 120 | Below 80 |
| Normal | 120–129 | 80–84 |
| High-Normal | 130–139 | 85–89 |
| Stage 1 Hypertension | 140–159 | 90–99 |
| Stage 2 Hypertension | 160–179 | 100–109 |
| Hypertensive Crisis | 180 or above | 110 or above |
A single high reading doesn't necessarily mean you have hypertension — readings can be temporarily elevated by stress, caffeine, or activity. Diagnosis is usually based on consistently elevated readings over multiple occasions.
What Causes Hypertension?
In most cases (around 90–95%), hypertension is primary (essential) — meaning it develops gradually without a single identifiable cause. Contributing factors include:
- Increasing age — arteries become stiffer over time
- Family history and genetics
- Being overweight or obese
- A diet high in salt (sodium)
- Physical inactivity
- Excessive alcohol consumption
- Chronic stress
- Smoking
The remaining cases are secondary hypertension — caused by an underlying condition such as kidney disease, thyroid disorders, or sleep apnoea.
Why It Matters: The Risks of Untreated Hypertension
Left unmanaged, high blood pressure places sustained strain on the cardiovascular system and can lead to:
- Heart attack — due to narrowed or hardened coronary arteries
- Stroke — either from blocked or ruptured blood vessels in the brain
- Heart failure — from the heart working harder over time
- Chronic kidney disease — kidneys are highly sensitive to blood pressure changes
- Vision loss — from damage to blood vessels in the eyes
Managing and Treating Hypertension
Lifestyle Changes
For many people, lifestyle modifications alone can bring blood pressure into a healthy range:
- Reduce salt intake — aim for less than 6g per day; most excess comes from processed foods
- Follow the DASH diet — rich in fruits, vegetables, wholegrains, and low-fat dairy
- Exercise regularly — 150 minutes of moderate aerobic activity per week
- Limit alcohol — to no more than 14 units per week spread across the week
- Stop smoking — smoking raises blood pressure and multiplies cardiovascular risk
- Manage stress — through mindfulness, relaxation techniques, or talking therapy
Medication
When lifestyle changes aren't sufficient, antihypertensive medications are prescribed. Common classes include ACE inhibitors, calcium channel blockers, angiotensin receptor blockers (ARBs), and diuretics. Many people require more than one medication to adequately control blood pressure — this is normal and not a sign that treatment has failed.
The Importance of Regular Monitoring
Because hypertension has no reliable symptoms, regular blood pressure checks are essential — especially if you're over 40 or have risk factors. Many pharmacies offer free blood pressure checks, and home monitors are affordable and easy to use. Knowing your numbers is one of the most important steps you can take for your long-term heart health.