Blood Pressure
Definition
Blood pressure is the force exerted by circulating blood on the walls of blood vessels, measured in millimeters of mercury (mmHg) as two numbers: systolic (pressure when the heart beats, upper number) over diastolic (pressure between beats, lower number). Normal blood pressure is below 120/80 mmHg. Elevated is 120โ129/<80, Stage 1 hypertension is 130โ139/80โ89, Stage 2 hypertension is 140+/90+, and hypertensive crisis is above 180/120 (seek emergency care). High blood pressure is called the 'silent killer' because it has no symptoms but dramatically increases risk of heart attack, stroke, and kidney disease.
Why is Blood Pressure Important?
Understanding Blood Pressure empowers you to take control of your personal health and wellness. Whether you are tracking body composition, planning nutrition, or evaluating fitness metrics, this concept provides the foundation for making informed health decisions backed by science.
Our health calculators make these metrics accessible and easy to compute, giving you instant, evidence-based results so you can focus on achieving your wellness goals rather than crunching numbers.
What is Blood Pressure?
Blood pressure (BP) is the force exerted by circulating blood on the walls of arteries, measured in millimeters of mercury (mmHg). It is expressed as two numbers: systolic (pressure during heartbeat, top number) over diastolic (pressure between beats, bottom number). Blood pressure is one of the most important vital signs monitored in clinical medicine.
Blood Pressure Categories (AHA/ACC 2017 Guidelines)
| Category | Systolic | Diastolic | Action |
|---|---|---|---|
| Normal | <120 | and <80 | No treatment โ maintain healthy lifestyle |
| Elevated | 120โ129 | and <80 | Lifestyle changes (diet, exercise, weight loss) |
| Stage 1 Hypertension | 130โ139 | or 80โ89 | Lifestyle + medication if high CVD risk |
| Stage 2 Hypertension | 140+ | or 90+ | Lifestyle + medication (typically 2 drugs) |
| Hypertensive Crisis | 180+ | and/or 120+ | Emergency โ seek immediate medical care |
Blood Pressure Risks
| Organ System | Risk from Uncontrolled High BP |
|---|---|
| Heart | Heart attack, heart failure, left ventricular hypertrophy |
| Brain | Stroke (both ischemic and hemorrhagic), cognitive decline |
| Kidneys | Chronic kidney disease, kidney failure |
| Eyes | Retinopathy, vision loss |
| Arteries | Atherosclerosis, peripheral artery disease, aneurysm |
How to Measure Accurately
- Sit quietly for 5 minutes before measuring
- Place the cuff on bare upper arm at heart level
- No caffeine, exercise, or smoking for 30 minutes prior
- Empty your bladder first (a full bladder raises BP 10โ15 mmHg)
- Take 2โ3 readings 1 minute apart and average them
- Measure at the same time each day (preferably morning)
- Use a validated, automatic upper-arm cuff (not wrist monitors)