How is hypertension actually diagnosed?

Not from a single reading. Diagnosis requires multiple readings on multiple visits, ideally combined with home monitoring or 24-hour ambulatory blood pressure measurement. White-coat hypertension (high readings only in clinical settings) is real and well-documented.

What's the difference between systolic and diastolic?

Systolic (top number) is the pressure when your heart contracts. Diastolic (bottom number) is the pressure when it relaxes between beats. Both matter, but systolic blood pressure is the stronger predictor of cardiovascular events in adults over 50.

Can lifestyle changes lower blood pressure?

Yes — meaningfully. The DASH diet lowers systolic by 8–14 mmHg in people with hypertension. Reducing sodium intake to under 1,500 mg per day, regular aerobic exercise, weight loss, limiting alcohol, and stress reduction each contribute. For stage 1 hypertension without other cardiovascular risks, lifestyle change is often the first-line treatment.

When should I take blood pressure medication?

When lifestyle change isn't enough or when overall cardiovascular risk is high. Most people with stage 2 hypertension need medication. The choice between thiazide diuretics, ACE inhibitors, ARBs, or calcium channel blockers depends on age, race, and coexisting conditions and should be made with a clinician.

How should I measure blood pressure at home?

Use a validated upper-arm cuff (not wrist), sit quietly for 5 minutes first, both feet flat on the floor, arm supported at heart level. Take two readings a minute apart, twice a day for 7 days. Average the readings excluding the first day. The British Hypertension Society and AHA both publish detailed home-monitoring protocols.

Why does my pulse pressure matter?

Pulse pressure (systolic minus diastolic) is a marker of arterial stiffness. A wide pulse pressure (above ~60 mmHg) in older adults is associated with higher cardiovascular risk independent of absolute blood pressure.

Blood Pressure Calculator — ACC/AHA

Blood Pressure Analyzer

ACC/AHA 2017 hypertension guideline · Stage classification

Implements a published clinical formula — see citation

Maintained by TheHealthTools team. Not medical advice.

Systolic (top number, mmHg)

Diastolic (bottom number, mmHg)

ACC/AHA 2017 Categories

Category	Systolic	Diastolic
Normal	< 120	and < 80
Elevated	120 – 129	and < 80
Stage 1 Hypertension	130 – 139	or 80 – 89
Stage 2 Hypertension	≥ 140	or ≥ 90
Hypertensive Crisis	> 180	and/or > 120

A single reading is a starting point, not a diagnosis

Hypertension is diagnosed from multiple readings on multiple visits, ideally combined with home or 24-hour ambulatory monitoring. White-coat hypertension — high readings only in clinical settings — is real and well-documented; treating it like sustained hypertension over-medicates patients. If a single high reading concerns you, the right next step is at least a week of careful home monitoring under your physician's guidance, not immediate medication.

When a high reading is an emergency

Above 180/120 mmHg with symptoms — chest pain, shortness of breath, severe headache, vision changes, weakness, or trouble speaking — is a hypertensive crisis. Call 911 (US), 999 (UK), 112 (EU), or 000 (AU) immediately. Above 180/120 without symptoms still needs same-day evaluation, but is not a 911 call.

What lowers blood pressure

The DASH eating pattern (rich in vegetables, fruit, whole grains, low-fat dairy, fish, poultry, beans, nuts; light on red and processed meats and sweets) lowers systolic blood pressure by 8–14 mmHg in people with hypertension — comparable to a single anti-hypertensive medication. Reducing sodium below 1,500 mg daily, regular aerobic exercise, weight loss in overweight individuals, limiting alcohol, and stress reduction each contribute additional reductions.

Source: Whelton PK, Carey RM, et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline. Hypertension. 2018;71(6):e13-e115.

Frequently asked questions

Per the 2017 ACC/AHA guideline, normal is below 120/80 mmHg. 120–129 systolic with diastolic under 80 is elevated. 130–139 systolic or 80–89 diastolic is stage 1 hypertension. 140 or higher systolic, or 90 or higher diastolic, is stage 2. Above 180/120 is hypertensive crisis — seek emergency care if you also have symptoms.