Core answer: Ideal adult blood pressure is below 120/80 mmHg; a clinic reading of ≥140/90 counts as hypertension, and a home reading of ≥135/85 is the warning line. Diagnosis requires elevated readings on 3 separate days — a single high reading (stress, post-exercise) proves nothing.
Blood pressure categories (clinic measurement, mmHg)
| Category | Systolic (top) | Diastolic (bottom) |
|---|---|---|
| Ideal | <120 | <80 |
| High-normal | 120–139 | 80–89 |
| Stage 1 hypertension | 140–159 | 90–99 |
| Stage 2 hypertension | 160–179 | 100–109 |
| Stage 3 hypertension | ≥180 | ≥110 |
When systolic and diastolic fall into different categories, the higher one wins. Isolated systolic hypertension (top ≥140, bottom <90) is the most common pattern in older adults.
Home vs clinic thresholds
| Method | Hypertension line | Notes |
|---|---|---|
| Clinic | ≥140/90 | diagnostic standard |
| Home self-test | ≥135/85 | stricter — removes white-coat effect |
| 24-hour ambulatory | avg ≥130/80 | night ≥120/70 also matters |
About 15% of people have "white-coat hypertension" (high at the clinic, normal at home); the reverse — "masked hypertension" (normal at the clinic, high at home) — is even more dangerous. That is the value of home monitoring.
Reference ranges by age
Diagnostic cutoffs do not change with age (uniform 140/90), but typical physiological readings drift upward:
| Age group | Common range |
|---|---|
| 18–40 | 90–120 / 60–80 |
| 41–60 | 100–130 / 65–85 |
| >60 | 110–140 / 70–90 |
| Children | percentile tables by age/height — needs pediatric evaluation |
Note: "higher blood pressure is normal when you get old" is a myth — older adults benefit from treatment just as clearly (general target <140/90, lower if tolerated).
Measuring correctly: 6 steps
- No smoking, coffee, strong tea or exercise 30 minutes before; empty your bladder
- Sit quietly for 5 minutes, back supported, feet flat, no crossed legs
- Cuff on the bare upper arm, lower edge 2–3 cm above the elbow crease, one-finger slack, at heart level
- No talking or moving during the reading
- Wait 1–2 minutes, take a second reading, average the two
- Measure morning (after waking and urinating) and evening (before bed); keep a 7-day log for your doctor
Reading three real cases
Case 1: three home days of 128/82, 131/79, 126/80 — average 128/80, high-normal. No medication needed, but time to cut salt and lose weight.
Case 2: 152/96 at the clinic, 132/84 at home — white-coat effect. Continue 7-day home monitoring plus 24-hour ambulatory if needed; no rush to diagnose.
Lifestyle intervention checklist
- Salt: under 5 g/day (one beer-bottle cap) — lowers systolic 5–6 mmHg
- Weight: every 1 kg lost drops systolic ~1 mmHg
- Exercise: 150 min/week of brisk walking — lowers 4–9 mmHg
- Alcohol and smoking: limit alcohol (men <25 g, women <15 g daily), quit smoking
- DASH diet: more vegetables, fruit, low-fat dairy, whole grains; less red meat and sugar
- Sleep: under 6 hours a night significantly raises hypertension risk
Common mistakes and myths
- "No symptoms means no problem" — hypertension is a silent killer; most patients feel nothing until organ damage is underway.
- "Stop the pills once readings are normal" — normal readings ARE the medication working; quitting causes rebound, and swings hurt vessels more than steady elevation. Any change must go through your doctor.
- "Digital cuffs are inaccurate" — a validated upper-arm device is perfectly reliable; technique is what matters. Wrist devices are error-prone and not recommended.
- "High bottom number doesn't matter" — elevated diastolic is hypertension too; common in younger patients, and the cardiovascular risk is just as real.
Use the [Blood Pressure Calculator](/c/health/blood-pressure) for instant classification and advice, and the [Heart Rate Calculator](/c/health/heart-rate) to assess cardiovascular status alongside.