Every blood pressure reading is two numbers — systolic over diastolic, written like 134/82 mmHg. On their own they are easy to misread. The American Heart Association and the American College of Cardiology (AHA/ACC) published a categorization in 2017 that turns those two numbers into a single, named category. BPTally uses exactly these thresholds, so this is the system behind the colors you see in the app.
The two numbers
- Systolic (the top number) is the pressure while your heart beats.
- Diastolic (the bottom number) is the pressure while your heart rests between beats.
A category is decided by whichever number is higher. If your systolic falls in one band and your diastolic in another, the higher band wins.
The 2017 AHA/ACC categories
| Category | Systolic (mmHg) | Diastolic (mmHg) | |
|---|---|---|---|
| Normal | below 120 | and | below 80 |
| Elevated | 120–129 | and | below 80 |
| Stage 1 hypertension | 130–139 | or | 80–89 |
| Stage 2 hypertension | 140 or higher | or | 90 or higher |
| Hypertensive crisis | higher than 180 | and/or | higher than 120 |
A reading in the hypertensive crisis range — especially with symptoms such as chest pain, shortness of breath, or visual changes — is the one category that calls for urgent medical attention rather than watchful logging.
Why a single reading is not a category
Blood pressure moves all day. It is higher after coffee, after climbing stairs, when you are stressed, and when a cuff is the wrong size or your arm is unsupported. That is why clinicians look at an average of many readings taken under consistent conditions, not a single number. A morning-and-evening logging habit over a couple of weeks tells a far more honest story than one tense reading in a waiting room.
How BPTally uses these thresholds
When you save a reading, BPTally classifies it against the AHA/ACC 2017 thresholds above and shows the matching category. Over time it computes your averages and standard deviation, and it can export a one-page PDF — the format your cardiologist actually reads. The categories are a mechanism for organizing your own measurements; BPTally is not a medical device and does not diagnose anything.
The bottom line
Learn the five names, remember that the higher number sets the category, and judge yourself on an average rather than a single reading. If you want the technique behind a trustworthy reading, see how to measure your blood pressure at home. And whatever your numbers say, a category is a prompt to talk to a qualified clinician — not a diagnosis on its own.
This article is for general education and is not medical advice. Always consult a qualified clinician about your blood pressure and any treatment decisions.