Understanding your blood pressure numbers

Blood pressure is the force your heart uses to push blood through your arteries. It's reported as two numbers — for example, 120/80 mmHg. The top number (systolic) measures the pressure when your heart contracts; the bottom number (diastolic) measures the pressure between beats.

What the numbers mean

Current international guidelines group readings into broad bands:

• **Normal:** less than 120/80 mmHg
• **Elevated:** 120–129 systolic and under 80 diastolic
• **Stage 1 hypertension:** 130–139 / 80–89 mmHg
• **Stage 2 hypertension:** 140/90 mmHg or higher
• **Hypertensive crisis:** above 180/120 mmHg — seek care immediately

A single high reading is not a diagnosis. Blood pressure varies through the day, with stress, caffeine, sleep, and even how recently you walked into the room. Diagnosis usually relies on an average of several readings, often taken at home over a week.

How to measure it well at home

• Sit quietly for five minutes first, feet flat on the floor, back supported.
• Use a validated upper-arm cuff sized to your arm — wrist cuffs are less reliable.
• Rest your arm at heart level on a table; don't talk during the reading.
• Take two readings a minute apart, morning and evening, for at least three days. Log the average.

When to act

Persistent elevation deserves a clinical conversation. A primary-care physician can order baseline labs and lifestyle counselling; if your readings stay high despite first-line changes, a referral to a cardiologist is appropriate. People with diabetes, kidney disease, or a family history of early cardiac events should have a lower threshold for specialist input — see our companion piece on when to see a cardiologist.

Lifestyle levers that actually move the number

• Reducing dietary sodium to under 2,300 mg/day (about a teaspoon of salt).
• 150 minutes of moderate aerobic activity per week.
• Losing 5–10% of body weight if overweight.
• Limiting alcohol to under one drink/day (women) or two (men).
• Treating sleep apnoea if snoring or daytime fatigue is present.

If you're researching specialist costs before an appointment, our cost guides include city-by-city pricing for common cardiac procedures.