What is Hypertension?
Hypertension is a chronic medical condition where the force of blood against artery walls is consistently too high, forcing the heart to work harder to pump blood. In adults, it is defined as:
- Systolic Pressure: ≥ 130 mmHg
- Diastolic Pressure: ≥ 80 mmHg
Blood Pressure Categories
| Category | Systolic (Top) | Diastolic (Bottom) |
|---|---|---|
| Normal | < 120 mmHg | < 80 mmHg |
| Elevated | 120–129 mmHg | < 80 mmHg |
| Stage 1 Hypertension | 130–139 mmHg | 80–89 mmHg |
| Stage 2 Hypertension | ≥ 140 mmHg | ≥ 90 mmHg |
| Hypertensive Crisis | > 180 mmHg | > 120 mmHg |
Blood Pressure Checker
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Types & Subtypes
1. Primary (Essential) Hypertension
Accounting for 90–95% of cases, this type develops gradually over many years. Key factors include genetics, aging, obesity, and lifestyle (high salt intake).
2. Secondary Hypertension
Occurs suddenly due to underlying conditions like kidney disease, adrenal gland tumors, or obstructive sleep apnea.
Other Subtypes
- Isolated Systolic: High systolic but normal diastolic (common in older adults).
- Resistant: High BP despite the use of 3+ medications.
- Malignant: Extremely high BP causing rapid organ damage.
Mechanisms of Disease
Hypertension is driven by a dysfunction in vascular resistance and blood volume regulation:
- Total Peripheral Resistance: Narrowing of small arterioles increases flow resistance.
- RAAS Overactivity: Excessive Angiotensin II causes vasoconstriction and salt retention.
- Endothelial Dysfunction: Loss of nitric oxide leads to vessel stiffening.
- Immune Response: Pro-inflammatory cells damage the vasculature and kidneys.
Effects on the Body
Chronic high pressure leads to Arteriosclerosis (stiffening of walls) and Left Ventricular Hypertrophy (thickening of the heart muscle). Major end-organ damage includes:
- Brain: Stroke and dementia.
- Heart: Heart attack and angina.
- Kidneys: Chronic kidney failure.
- Eyes: Vision loss (Retinopathy).