A good resting blood pressure is below 120/80 mmHg. That’s the threshold the American Heart Association defines as “normal,” and it’s the range associated with the lowest cardiovascular risk. But the two numbers in a blood pressure reading tell different stories about your heart and arteries, and understanding both gives you a much clearer picture of where you stand.
What the Numbers Mean
Blood pressure is recorded as two numbers. The top number (systolic) measures the force your blood exerts on artery walls when your heart beats. The bottom number (diastolic) measures that force between beats, when your heart is resting. Both are expressed in millimeters of mercury, or mmHg.
A reading of 115/75 is often cited as a baseline for cardiovascular risk calculations. Starting from that point, your risk of heart disease and stroke doubles with every increase of 20 points systolic or 10 points diastolic. So the difference between 115/75 and 135/85 isn’t minor. It represents roughly a twofold jump in risk, even though 135/85 might not feel alarming on its own.
Blood Pressure Categories for Adults
The current categories break down like this:
- 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
Notice that stage 1 and stage 2 use “or” rather than “and.” If either number crosses the threshold, the higher category applies. You could have a systolic of 118 but a diastolic of 85, and that still qualifies as stage 1 hypertension because of the bottom number alone.
The “elevated” category is a warning zone. Your systolic pressure is creeping up, but your diastolic is still fine. Without lifestyle changes, elevated blood pressure tends to progress to stage 1 hypertension over time.
Can Blood Pressure Be Too Low?
A reading below 90/60 mmHg is generally considered low blood pressure, or hypotension. But low numbers only matter if they cause symptoms. Some people walk around at 95/60 and feel perfectly fine. Others get dizzy, lightheaded, or faint when their pressure drops.
What often triggers symptoms isn’t the absolute number but a sudden change. A drop of just 20 points in systolic pressure, say from 110 to 90, can make you feel dizzy or cause you to faint. This is why standing up too quickly sometimes causes a head rush: blood temporarily pools in your legs, and your systolic pressure dips before your body compensates.
Pulse Pressure: A Number Worth Knowing
Subtract your diastolic reading from your systolic reading, and you get your pulse pressure. For a blood pressure of 120/80, the pulse pressure is 40, which is considered healthy. A pulse pressure consistently above 40 is a warning sign, and above 60 is a recognized risk factor for heart disease, particularly in older adults.
A wide pulse pressure usually means your large arteries have stiffened. Healthy arteries are elastic and absorb each heartbeat like a shock absorber. When they stiffen from age, high blood pressure, or cholesterol buildup, the systolic number climbs while the diastolic stays the same or even drops. This is why someone might have a reading like 155/70. That looks like only the top number is a problem, but the pulse pressure of 85 tells a more concerning story about arterial damage.
Blood Pressure in Older Adults
The same categories apply at any age, but the pattern of high blood pressure changes as you get older. Older adults commonly develop what’s called isolated systolic hypertension, where the top number is 130 or higher but the bottom number stays below 80. This happens because large arteries stiffen with age, which pushes systolic pressure up without affecting diastolic pressure.
A major NIH-funded trial called SPRINT found that lowering systolic blood pressure to below 120 in adults age 50 and older significantly reduced the risk of cardiovascular disease and death. That said, treatment targets for older adults often factor in other health conditions, medication side effects, and overall fitness. A 75-year-old with multiple health issues may have a different target than a healthy 55-year-old.
Blood Pressure in Children
For children and adolescents, there’s no single “good” number. Normal blood pressure in kids is defined relative to their age, sex, and height. A reading that’s fine for a tall 14-year-old boy might be elevated for a smaller 8-year-old girl. Pediatricians use reference charts with percentile rankings, and blood pressure below the 90th percentile for a child’s demographic profile is considered normal. If your child’s blood pressure comes up at a checkup, the pediatrician will interpret it using these charts rather than the adult categories.
How to Get an Accurate Reading
The word “resting” in resting blood pressure matters more than most people realize. Your blood pressure fluctuates throughout the day based on activity, stress, food, and even conversation. To get a number that actually reflects your baseline cardiovascular health, the conditions have to be right.
Sit in a chair (not a couch) with your back straight, feet flat on the floor, and legs uncrossed. Rest the arm you’re measuring on a table so it’s level with your heart, and let it relax completely. Stay in this position for at least five minutes before taking the reading. Don’t talk, scroll your phone, or watch videos during the measurement.
For the 30 minutes before measuring, avoid caffeine, tobacco, food, and exercise. Empty your bladder first, since a full bladder can raise systolic pressure by 10 to 15 points. These details sound fussy, but skipping them can easily push a normal reading into the elevated or stage 1 range, giving you a falsely high result. If you’re tracking blood pressure at home, try to measure at the same time each day and take two or three readings a minute apart, then average them.
What Elevated Readings Actually Mean for You
A single high reading doesn’t mean you have hypertension. Blood pressure is highly variable. Stress, a bad night’s sleep, or rushing to an appointment can all temporarily push your numbers up. This is why a diagnosis of high blood pressure typically requires elevated readings on multiple occasions, often over weeks.
If your readings consistently land in the elevated or stage 1 range, the first-line approach is usually lifestyle changes: regular aerobic exercise, reducing sodium intake, managing stress, maintaining a healthy weight, and limiting alcohol. These adjustments can lower systolic pressure by 5 to 15 points in many people, which is enough to move from stage 1 back into the normal range. Medication becomes part of the conversation when lifestyle changes aren’t enough or when readings reach stage 2 levels.