A normal blood pressure is below 120/80 mmHg. That means the top number (systolic) stays under 120 and the bottom number (diastolic) stays under 80. This threshold applies to all adults regardless of age, based on the most current guidelines from the American Heart Association and American College of Cardiology, updated in 2025.
What the Two Numbers Mean
Blood pressure is written as one number over another, like 115/75. The top number, systolic pressure, measures the force of blood against your artery walls when your heart beats and pushes blood out. The bottom number, diastolic pressure, measures that same force between beats, when your heart is resting. Both numbers matter, but systolic pressure becomes especially important after age 50 because arteries stiffen over time and plaque builds up, making that top number a stronger predictor of heart disease risk.
All Five Blood Pressure Categories
Your reading falls into one of these ranges:
- 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
- Hypertensive crisis: above 180 systolic and/or above 120 diastolic
Notice the word “or” in the hypertension categories. If either number crosses the threshold, the higher category applies. So a reading of 125/92 counts as stage 1 hypertension even though the top number looks fine, because the bottom number is in the 80 to 89 range.
These categories replaced older guidelines that set the hypertension cutoff at 140/90 for people under 65 and 150/80 for those 65 and older. The current framework uses the same thresholds for all adults.
When Blood Pressure Is Too Low
A reading below 90/60 is generally considered low blood pressure. Unlike high blood pressure, low blood pressure is only a concern when it causes symptoms. Those symptoms include dizziness, blurred vision, fainting, fatigue, and trouble concentrating. A drop of just 20 mmHg from your usual reading can be enough to make you feel lightheaded.
Extreme drops can lead to shock, which involves cold and clammy skin, confusion, rapid shallow breathing, and a weak pulse. This is rare and usually tied to an underlying cause like severe dehydration, blood loss, or an allergic reaction.
Why Your Reading Might Be Wrong
Blood pressure is surprisingly easy to measure incorrectly, and small mistakes can shift your numbers by 10 mmHg or more. For an accurate reading, you need to sit quietly for three to five minutes beforehand, without talking or moving around. Your arm should rest on a flat surface like a table at heart level. Holding your arm up yourself, even briefly, raises the reading because of the muscle effort involved.
The cuff goes on bare skin on your upper arm, not over a sleeve. Rolling up a tight sleeve can act like a tourniquet and skew results. The bottom edge of the cuff should sit about two to three centimeters above the crease of your elbow, and the cuff size matters: the inflatable part should wrap around at least 75% of your arm. A cuff that’s too small gives artificially high readings.
Even with perfect technique, your reading can vary depending on the setting. About 14% of people have what’s called white coat hypertension, where their blood pressure reads high in a medical office but is normal at home. Roughly 10% have the opposite problem, called masked hypertension, where office readings look fine but blood pressure runs high in daily life. Home monitoring with a validated device gives a more complete picture, especially if your numbers are borderline.
What Pushes Blood Pressure Up
Blood pressure rises with age as arteries lose flexibility, but lifestyle plays a major role at every stage of life. Excess sodium, low potassium intake, physical inactivity, excess weight, heavy alcohol use, and chronic stress all contribute. Genetics set a baseline level of risk, but most people with high blood pressure can lower their numbers through changes they control.
The DASH diet, which emphasizes fruits, vegetables, whole grains, and lean protein while limiting sodium and saturated fat, lowers systolic pressure by about 3 mmHg and diastolic pressure by about 2.5 mmHg on average. That may sound modest, but at a population level, even small reductions in blood pressure translate to meaningfully lower rates of heart attack and stroke. For people starting with higher readings, the effect tends to be larger.
Regular aerobic exercise, maintaining a healthy weight, limiting alcohol, and reducing sodium intake each contribute additional reductions. Combined, these changes can rival the effect of medication for people with stage 1 hypertension.
What a Hypertensive Crisis Looks Like
A reading of 180/120 or higher is a hypertensive crisis. If that number appears alongside symptoms like severe headache, chest pain, vision changes, confusion, difficulty speaking, or sudden weakness on one side of the body, it’s a medical emergency that requires calling 911. These symptoms suggest organs like the brain, heart, or kidneys are being damaged by the pressure. A reading that high without symptoms still needs prompt medical attention, typically within hours rather than minutes.