Blood pressure is expressed as two numbers: systolic (pressure when the heart contracts) over diastolic (pressure between beats). Normal is below 120/80 mmHg. Elevated is 120–129/<80. Stage 1 hypertension is 130–139/80–89. Stage 2 is ≥140/≥90. Hypertensive crisis — requiring urgent care — is >180/>120. These thresholds were revised in 2017 ACC/AHA guidelines and reflect the cardiovascular risk that begins well below the old 140/90 cutoff.
The pathophysiology involves arterial stiffness, endothelial dysfunction, and compensatory cardiac remodeling. The heart works harder to push against elevated resistance, eventually leading to left ventricular hypertrophy and, over time, heart failure. In the kidneys, elevated pressure damages the glomeruli, accelerating chronic kidney disease. In the brain, small vessel damage increases stroke risk and contributes to vascular dementia.
Lifestyle modification is the foundation of treatment regardless of medication status: dietary sodium restriction (target <2,300 mg/day, ideally <1,500 mg in high-risk patients), the DASH diet, regular aerobic exercise (150 minutes/week of moderate-intensity), weight loss if applicable, alcohol moderation, and smoking cessation. These interventions can reduce systolic blood pressure by 10–20 mmHg independently.
When medication is needed, first-line agents include thiazide diuretics, ACE inhibitors, ARBs, and calcium channel blockers. Choice depends on comorbidities: ACE inhibitors/ARBs in diabetic nephropathy, beta-blockers in heart failure with reduced ejection fraction. Combination therapy is often required to reach goal. Blood pressure management is lifelong — medication compliance, home monitoring, and regular follow-up are non-negotiable.