Blood pressure is measured in millimeters of mercury (mmHg) with two numbers:
- Systolic (top number): Pressure during a heartbeat
- Diastolic (bottom number): Pressure between heartbeats
Categories
- Normal: Below 120/80
- Elevated: 120–129 / below 80
- High Stage 1: 130–139 / 80–89
- High Stage 2: 140+ / 90+
- Crisis: 180+ / 120+ (seek emergency care)
High blood pressure (hypertension) increases risk of heart disease, stroke, and kidney damage. It often has no symptoms, earning it the name "silent killer."
Why Two Readings on Different Occasions Matter
A single high reading doesn't confirm hypertension — blood pressure fluctuates with stress, caffeine, recent activity, and even the anxiety of being at a doctor's office ("white coat syndrome"). Diagnosis typically requires elevated readings across multiple separate occasions, or home monitoring over several days.
Lifestyle Factors That Move the Numbers
Sodium intake, body weight, alcohol consumption, physical activity, and sleep quality all measurably affect blood pressure. The DASH diet (Dietary Approaches to Stop Hypertension) has been clinically shown to lower systolic pressure by several points within weeks, often before medication is even considered for borderline cases.