A good blood pressure reading is below 120/80 mmHg. That’s the threshold the American Heart Association defines as “normal,” and the 2025 AHA/ACC guidelines now encourage most adults to stay under 120 systolic to reduce cardiovascular risk over the long term. But blood pressure isn’t just pass/fail. It exists on a spectrum, and knowing where you fall on that spectrum tells you a lot about your heart health.
What the Two Numbers Mean
Blood pressure is always written as two numbers. The top number (systolic) measures the force of blood against your artery walls when your heart beats. It depends heavily on how flexible your large arteries are, which is why it tends to rise with age as arteries stiffen. The bottom number (diastolic) measures that same pressure between beats, when your heart is resting and refilling with blood. It reflects the resistance in your smaller blood vessels.
Both numbers matter, though systolic pressure gets more attention because it’s a stronger predictor of heart attack and stroke, especially after middle age. In older adults, it’s common to see a high systolic number paired with a normal diastolic number, a pattern called isolated systolic hypertension.
Blood Pressure Categories
The current classification system breaks readings into four main categories:
- Normal: below 120 systolic and below 80 diastolic
- Elevated: 120 to 129 systolic with diastolic still below 80
- Stage 1 hypertension: 130 to 139 systolic, or 80 to 89 diastolic
- Stage 2 hypertension: 140 or higher systolic, or 90 or higher diastolic
Only one number needs to be high for the reading to count as elevated or hypertensive. If your systolic is 135 but your diastolic is 75, that’s still stage 1 hypertension based on the top number alone.
How Each Category Affects Your Risk
A large meta-analysis published in The BMJ tracked cardiovascular outcomes across blood pressure categories in young adults and found a clear, graded relationship. Compared to people with optimal pressure (under 120/80), those with readings in the “high normal” range (what guidelines now call “elevated”) had a 35% higher risk of cardiovascular events. Stage 1 hypertension nearly doubled the risk, and stage 2 hypertension tripled it.
The pattern held for specific conditions. Stroke risk climbed from 14% higher in the normal range to 27% higher in the elevated range, 89% higher with stage 1 hypertension, and 187% higher with stage 2. Heart disease followed a similar trajectory: 25% higher risk at elevated levels, 65% higher at stage 1, and 127% higher at stage 2. These aren’t small jumps, and they accumulate over decades.
Updated 2025 Guidelines Push Lower
The most recent AHA/ACC guidelines, released in 2025, set more aggressive targets than previous versions. For adults with higher cardiovascular risk (defined as a 10-year risk of 7.5% or greater), the goal is a systolic pressure below 130, with strong encouragement to get below 120. For people at lower cardiovascular risk, below 130 is considered reasonable, but the guidelines still encourage aiming for under 120 to prevent blood pressure from creeping up over time.
The diastolic target is below 80 across the board. These recommendations are backed in part by the SPRINT trial, a major NIH-funded study that found lowering systolic pressure below 120 in adults over 50 significantly reduced the risk of cardiovascular disease and death.
Blood Pressure Goals for Older Adults
Blood pressure naturally rises with age as arteries lose elasticity, so the question of how aggressively to lower it in older adults gets complicated. The same SPRINT trial that supports a target under 120 included adults well into their 70s and 80s and still showed benefits. But older adults are also more vulnerable to the downsides of very low pressure, including dizziness, falls, and fainting.
The decision about how low to go typically involves weighing other health conditions and overall fitness. Someone who is 75 and otherwise healthy may benefit from a target under 120, while someone the same age with multiple chronic conditions might aim for a less aggressive number. There’s no single cutoff where the rules change based on age alone.
When Blood Pressure Is Too Low
While most of the focus is on high blood pressure, readings below 90/60 are generally considered low. Low blood pressure on its own isn’t necessarily a problem. Some people run naturally low without any symptoms. It only becomes a concern when it causes dizziness, blurred vision, fatigue, fainting, or trouble concentrating.
Sudden drops are more dangerous than consistently low readings. A fall of just 20 points in systolic pressure, say from 110 to 90, can be enough to make you dizzy or pass out. Signs of dangerously low blood pressure include cold and clammy skin, rapid shallow breathing, confusion, and a weak pulse. That situation requires emergency care.
Getting an Accurate Reading
Blood pressure is notoriously sensitive to how and when you measure it. A reading taken after rushing into a clinic can be 10 to 20 points higher than your true resting pressure. To get an accurate number at home, sit in a chair with your back supported and your feet flat on the floor. Rest for at least five minutes before taking a measurement.
Place the cuff on your bare upper arm, about one inch above the bend of your elbow, with the sensor centered over the front of your arm. The cuff should be snug enough that only two fingertips fit under its top edge. Keep your arm stretched out at heart level, palm facing up. Stay still and quiet while the machine runs. After the first reading, wait one to two minutes and take a second one. The average of the two gives you a more reliable number.
Caffeine, exercise, a full bladder, and even talking during the measurement can all inflate your results. If you’re tracking your blood pressure at home, take readings at the same time each day, ideally in the morning before coffee, to spot meaningful trends rather than random fluctuations.