A normal blood pressure reading is less than 120/80 mm Hg. That first number (systolic) measures the pressure in your arteries when your heart beats, and the second number (diastolic) measures the pressure between beats. Once either number climbs above those thresholds, your cardiovascular risk starts rising.
Blood Pressure Categories
The American Heart Association breaks blood pressure into five categories based on your systolic and diastolic numbers:
- Normal: Below 120 systolic and below 80 diastolic
- Elevated: 120 to 129 systolic with diastolic still below 80
- Stage 1 high blood pressure: 130 to 139 systolic or 80 to 89 diastolic
- Stage 2 high blood pressure: 140 or higher systolic or 90 or higher diastolic
- Hypertensive crisis: Above 180 systolic and/or above 120 diastolic
Notice that only the “normal” category requires both numbers to be in range. For the high blood pressure stages, either number being elevated is enough to place you in that category. So a reading of 135/75 counts as stage 1 high blood pressure even though the diastolic number looks fine.
Why Every 20 Points Matters
Blood pressure isn’t something that suddenly becomes dangerous at a specific cutoff. Risk rises on a curve. For every 20 mm Hg increase in systolic pressure or every 10 mm Hg increase in diastolic pressure, the risk of dying from stroke or heart disease roughly doubles. That relationship holds across a wide range of readings, which is why even “elevated” blood pressure (120 to 129 systolic) deserves attention before it progresses to full hypertension.
Targets for Older Adults
If you’re over 65, your ideal blood pressure target may look slightly different. For adults aged 65 to 80 who are otherwise healthy and active, guidelines generally aim for systolic pressure below 140. For people over 80, the target loosens to below 150 in many cases, though it can be pushed to below 140 depending on how well someone functions day to day.
This flexibility exists because blood pressure that drops too low in older adults can cause dizziness, falls, and fainting. For frail individuals or those with significant cognitive decline, doctors often reduce or stop blood pressure medications if systolic pressure falls below 130, since the risks of low pressure can outweigh the benefits of treatment. The practical safety window for many older adults on medication is a systolic reading between 130 and 150.
Blood Pressure in Children
There’s no single “normal” number for kids. In children and teenagers, blood pressure is evaluated using percentile charts that account for age, sex, and height. A reading at or above the 90th percentile for a child’s demographic group is considered elevated, and at or above the 95th percentile is considered high. Your pediatrician uses these charts at routine checkups, so there’s no need to memorize them, but it’s worth knowing that a number perfectly normal for an adult could be high for a child.
When Blood Pressure Is Too Low
Low blood pressure is generally defined as a reading below 90/60 mm Hg. Unlike high blood pressure, low blood pressure is only considered a problem if it causes symptoms. Some people walk around with naturally low readings and feel perfectly fine.
What matters more than the absolute number is a sudden drop. A decrease of just 20 mm Hg in systolic pressure, say from 110 down to 90, can cause dizziness or fainting. This commonly happens when standing up quickly, after eating a large meal, or as a side effect of certain medications.
How to Get an Accurate Reading
A single high reading doesn’t necessarily mean you have high blood pressure. How you take the measurement matters a lot. The CDC recommends sitting in a comfortable chair with your back supported for at least five minutes before taking a reading. Your arm should rest on a table at chest height with the cuff snug around bare skin.
About 14% of people have what’s called white coat hypertension, where blood pressure reads high in a clinical setting but is normal at home. Another 10% have the opposite problem, called masked hypertension, where readings look fine at the doctor’s office but run high the rest of the time. Home monitoring with a validated cuff can catch both patterns. Take readings at the same time each day, ideally morning and evening, and bring the log to your next appointment.
Lifestyle Changes That Lower Blood Pressure
If your numbers are in the elevated or stage 1 range, lifestyle changes alone can sometimes bring them back to normal. Cutting sodium intake is one of the most effective single changes you can make. In clinical trials, reducing sodium from a high intake to a low intake lowered systolic pressure by about 5 to 7 mm Hg within four weeks. That’s roughly the same effect as adding a blood pressure medication.
A dietary pattern rich in fruits, vegetables, whole grains, and low-fat dairy (often called the DASH diet) lowers systolic pressure by about 4 mm Hg on its own, with most of that effect kicking in within the first week. Combining that eating pattern with sodium reduction amplifies the benefit. Regular aerobic exercise, maintaining a healthy weight, limiting alcohol, and managing stress all contribute additional reductions that stack on top of each other.
When a Reading Is an Emergency
A blood pressure reading of 180/120 or higher is a hypertensive crisis. If you see that number on your monitor and have no symptoms, sit quietly for five minutes and recheck. If it’s still that high, contact your doctor promptly.
If that reading comes with any of the following symptoms, call 911: chest pain, severe headache, vision changes or sudden blurry vision, difficulty speaking, sudden weakness on one side of your body, confusion, or seizures. These signs suggest that the extreme pressure is actively damaging organs, and treatment within minutes can be the difference between full recovery and permanent harm.