Understanding Your Numbers
Blood pressure is recorded as two numbers, written as a ratio (e.g., 120/80).
- Systolic (The top number): Measures the pressure in your arteries when your heart beats and pumps blood.
- Diastolic (The bottom number): Measures the pressure in your arteries when your heart rests between beats.
If the measurement reads 120 systolic and 80 diastolic, you would say, "120 over 80," or write, "120/80 mmHg." Note that a diagnosis of high blood pressure must be confirmed with a medical professional, usually based on an average of two or more carefully measured readings obtained on two or more occasions.
The American Heart Association (AHA) Guidelines
In 2017, the American College of Cardiology and the American Heart Association updated the clinical guidelines for high blood pressure. They eliminated the category of "prehypertension" and lowered the threshold for hypertension.
| Category | Systolic (Top) | Diastolic (Bottom) |
|---|---|---|
| Normal | Less than 120 | Less than 80 |
| Elevated | 120 – 129 | Less than 80 |
| Hypertension Stage 1 | 130 – 139 | 80 – 89 |
| Hypertension Stage 2 | 140 or higher | 90 or higher |
| Hypertensive Crisis | Higher than 180 | Higher than 120 |
Tips for an Accurate Reading
- Don't smoke, drink caffeinated beverages, or exercise within 30 minutes before measuring.
- Empty your bladder and ensure at least 5 minutes of quiet rest before measurements.
- Sit with your back straight and supported (on a dining chair, rather than a sofa). Your feet should be flat on the floor.
- Your arm should be supported on a flat surface (such as a table) with the upper arm at heart level.