A normal blood pressure reading is less than 120/80 mm Hg. That means the top number (systolic) stays below 120 and the bottom number (diastolic) stays below 80. Once either number climbs above those thresholds, your cardiovascular risk starts to increase, even if you feel perfectly fine.
What the Two Numbers Mean
A blood pressure reading gives you two numbers, like 118/76. The top number, systolic pressure, measures the force your blood exerts on artery walls when your heart beats. The bottom number, diastolic pressure, measures that force between beats, when your heart is resting. Both numbers matter, but systolic pressure tends to rise with age and is the primary concern for people over 50. In older adults, it’s common to see a high systolic number paired with a normal diastolic number, a pattern called isolated systolic hypertension caused by age-related stiffening of the arteries.
Blood Pressure Categories for Adults
The American Heart Association breaks blood pressure into four categories:
- Normal: Less than 120 systolic and less than 80 diastolic. No intervention needed beyond maintaining healthy habits.
- Elevated: 120 to 129 systolic with a diastolic still under 80. This is a warning zone. Without changes, elevated blood pressure typically progresses to full hypertension.
- Stage 1 hypertension: 130 to 139 systolic, or 80 to 89 diastolic. Lifestyle changes are the first line of defense, and medication may be recommended depending on your overall cardiovascular risk.
- Stage 2 hypertension: 140 or higher systolic, or 90 or higher diastolic. This stage usually requires both lifestyle changes and medication.
Notice the word “or” in those hypertension categories. If either number is elevated, not just both, the higher category applies. A reading of 145/78 is Stage 2 hypertension even though the diastolic number looks fine.
Targets for Older Adults
The general target of less than 120/80 applies across adulthood, but treatment decisions for people over 65 get more nuanced. Older adults are more likely to have other health conditions, take multiple medications, or experience side effects like dizziness from aggressive blood pressure lowering. For these reasons, doctors often set individualized targets that balance cardiovascular protection against the risk of falls or other complications.
That said, a major NIH-funded trial called SPRINT found that lowering systolic pressure to less than 120 in adults age 50 and older significantly reduced the risk of cardiovascular disease and death. So while some older adults may have a slightly higher treatment target for practical reasons, the cardiovascular benefit of lower pressure is clear across age groups.
Blood Pressure During Pregnancy
Pregnancy changes the equation. A reading of 140/90 or higher on two separate occasions at least four hours apart is classified as high blood pressure during pregnancy. A reading of 160/110 or higher on two or more occasions is considered severe. Both require close monitoring because elevated blood pressure during pregnancy can signal preeclampsia, a serious condition that affects organ function and can be dangerous for both the mother and baby. If you’re pregnant and tracking your numbers at home, those are the thresholds to know.
Blood Pressure in Children
Children don’t use the same fixed numbers as adults. Instead, a child’s blood pressure is compared against percentiles based on their age, sex, and height. A reading at or above the 95th percentile for their demographic group is considered high. This means there’s no single “normal” number for kids. Your pediatrician tracks these percentiles over time and will flag any concerning trends.
When Blood Pressure Becomes an Emergency
A reading of 180/120 or higher is a hypertensive crisis. This is a medical emergency. Symptoms can include severe headache, chest pain, shortness of breath, blurred vision, confusion, nausea, and seizures. If you see a reading this high and experience any of those symptoms, call 911. Even without symptoms, a reading at this level needs urgent medical evaluation.
How to Get an Accurate Reading
A single reading can be misleading. Blood pressure fluctuates throughout the day based on stress, caffeine, activity, and even whether you need to use the bathroom. To get a number you can trust, the CDC recommends a specific routine:
- Timing: Don’t eat, drink, or exercise for 30 minutes before measuring. Empty your bladder first.
- Position: Sit in a chair with your back supported for at least five minutes. Keep both feet flat on the floor and your legs uncrossed.
- Arm placement: Rest your arm on a table at chest height. The cuff should sit on bare skin, not over a sleeve.
- During the reading: Don’t talk. Stay still.
A cuff that’s too small will give an artificially high reading, and one that’s too large will read low. If you’re using a home monitor, make sure the cuff fits your arm circumference. Most monitors come with a standard cuff and offer a larger size separately.
For the most reliable picture, take two readings one minute apart and average them. Do this at the same time each day for several days before drawing conclusions. A single high reading at the doctor’s office, sometimes called “white coat hypertension,” doesn’t necessarily mean you have a blood pressure problem. Patterns over time are what matter.