Normal blood pressure is a reading below 120/80 mmHg. That means the top number (systolic) is under 120 and the bottom number (diastolic) is under 80. Once either number crosses those thresholds, your blood pressure falls into progressively higher risk categories, from “elevated” all the way to stage 2 hypertension.
What the Two Numbers Mean
A blood pressure reading gives you two numbers, always written as one over the other (like 115/75). The top number, systolic pressure, measures the force inside your arteries when your heart beats and pushes blood out. The bottom number, diastolic pressure, measures that force between beats, when your heart is resting. Both numbers matter, and either one being too high is enough to move you into a higher category.
Blood Pressure Categories for Adults
The American Heart Association breaks adult blood pressure into four categories:
- Normal: below 120 systolic and below 80 diastolic
- Elevated: 120 to 129 systolic and below 80 diastolic
- Stage 1 hypertension: 130 to 139 systolic or 80 to 89 diastolic
- Stage 2 hypertension: 140 or higher systolic or 90 or higher diastolic
Notice that for normal blood pressure, both numbers need to be under the threshold. For hypertension, only one number needs to be elevated. So a reading of 135/75 still qualifies as stage 1 hypertension even though the bottom number looks fine.
European guidelines draw the line differently. The 2024 European Society of Cardiology guidelines define hypertension as 140/90 or higher, placing the threshold 10 points above the American cutoff for the top number. The European guidelines also avoid calling any blood pressure level “normal” or “optimal,” since cardiovascular risk starts rising at readings well below 120, particularly in women. They use the term “non-elevated” for anything under 120/70 and call 120 to 139 over 70 to 89 “elevated.”
Why “Elevated” Still Matters
A reading in the elevated range (120 to 129 over less than 80) might sound harmless, but it carries real consequences over time. A large prospective study published in the Journal of the American Heart Association found that people with elevated blood pressure had a 31% higher ten-year risk of cardiovascular disease compared to people with normal readings. Stage 1 hypertension raised that risk by 35%, and stage 2 more than doubled it.
The population-level impact of stage 1 hypertension was far larger than elevated blood pressure, accounting for roughly 10% of all cardiovascular events in the study population. Elevated blood pressure accounted for less than 1%. That gap exists because stage 1 hypertension is more common and pushes risk higher per person. But it also means that catching your blood pressure while it’s still in the elevated range, before it crosses into hypertension, gives you the most room to change course with lifestyle adjustments alone.
Blood Pressure in Older Adults
Blood pressure tends to rise with age as arteries stiffen, so many adults over 65 have readings that would be classified as hypertension. The question of how aggressively to treat it gets more complicated in older adults because of other health conditions and medication side effects like dizziness or falls.
A major NIH-funded trial called SPRINT found that lowering systolic blood pressure to below 120 in adults age 50 and older significantly reduced cardiovascular disease and death. That finding pushed many clinicians toward tighter targets for older patients who can tolerate treatment. But the right target for any individual depends on their overall health, other medications, and how they respond to treatment.
How Blood Pressure Is Defined in Children
Children don’t have a single “normal” number. Instead, pediatric blood pressure is evaluated using percentile charts that account for age, sex, and height. A child’s reading is compared to other children of the same size and age. Blood pressure at or above the 95th percentile is considered hypertension in children, while readings between the 90th and 95th percentiles are considered elevated. A 10-year-old boy and a 15-year-old girl will have very different normal ranges, so there’s no single number to memorize.
Your Blood Pressure Changes Throughout the Day
Blood pressure isn’t static. It rises when you exercise, feel stressed, or drink caffeine, and drops when you sleep. In healthy people, blood pressure falls by 10% to 20% during nighttime sleep compared to daytime levels. This is called “dipping,” and it’s considered a normal, healthy pattern. People whose blood pressure doesn’t dip at night face a higher risk of heart disease and stroke, even if their daytime readings look fine.
This natural variability is why a single reading at the doctor’s office isn’t always reliable. Some people experience “white coat hypertension,” where their blood pressure reads high in a clinical setting but is normal at home. The opposite also happens: “masked hypertension” means your readings look normal in the office but run high in daily life. Both patterns carry different risks, and home monitoring or 24-hour ambulatory monitoring can help sort them out.
How to Get an Accurate Reading
The way you take your blood pressure matters as much as the number you get. Small details can swing a reading by 10 to 20 points, enough to push a normal result into the elevated range or vice versa. The CDC recommends the following steps for an accurate measurement:
- Don’t eat or drink for 30 minutes beforehand
- Empty your bladder before the reading
- Sit with your back supported for at least 5 minutes before measuring
- Keep both feet flat on the floor with legs uncrossed
- Rest your arm on a table at chest height with the cuff against bare skin
- Stay silent during the measurement
Crossing your legs can raise your reading by several points. So can talking, a full bladder, or having the cuff over a shirt sleeve. If you’ve ever gotten a surprisingly high reading at a pharmacy kiosk or during a rushed doctor’s visit, poor technique is a likely explanation. When monitoring at home, take two or three readings a minute apart and average them for the most reliable result.
What Affects Your Blood Pressure Over Time
Genetics play a significant role, but the biggest modifiable factors are sodium intake, body weight, physical activity, and alcohol consumption. Consistently high sodium intake raises blood pressure by causing the body to retain fluid, which increases the volume of blood pushing against artery walls. Excess body weight forces the heart to work harder to supply blood to more tissue, and that extra workload raises pressure over time.
Regular aerobic exercise, even moderate-intensity walking, can lower systolic blood pressure by 5 to 8 points in people with hypertension. Reducing sodium intake to under 2,300 mg per day (roughly one teaspoon of table salt) produces a similar effect. For people in the elevated range, these changes alone are often enough to bring readings back below 120/80 without medication.