Blood Pressure RangesUnderstanding What Your Numbers Mean
Blood pressure is measured in millimeters of mercury (mmHg) and expressed as two numbers: systolic pressure (the top number) over diastolic pressure (the bottom number). These numbers place your reading into specific categories that guide treatment decisions and indicate cardiovascular risk.
Understanding where your blood pressure falls—and what that means for your health—empowers you to take appropriate action, whether that's maintaining healthy habits or seeking medical care.
Blood Pressure Categories
Normal Blood Pressure
Less than 120/80 mmHg
Normal blood pressure means your cardiovascular system is functioning efficiently. Blood flows through your arteries without excessive force, and your heart doesn't have to work harder than necessary. This is the range to maintain throughout life.
If your blood pressure is normal, focus on keeping it there through healthy lifestyle habits: regular physical activity, a balanced diet low in sodium, maintaining a healthy weight, limiting alcohol, and managing stress. Continue monitoring periodically—blood pressure can change over time.
Elevated Blood Pressure
120-129 systolic AND less than 80 diastolic
Elevated blood pressure is a warning sign. While not yet classified as hypertension, readings in this range indicate your blood pressure is trending upward and may progress to high blood pressure without intervention. About 37% of people with elevated blood pressure develop hypertension within four years.
This is the ideal time to make lifestyle changes. The same modifications that treat hypertension—diet, exercise, weight management—can prevent it from developing. Medication isn't typically prescribed for elevated blood pressure, but lifestyle intervention is strongly recommended.
High Blood Pressure Stage 1
130-139 systolic OR 80-89 diastolic
Stage 1 hypertension represents the beginning of clinically significant high blood pressure. At this level, cardiovascular risk begins increasing measurably. The risk of heart attack, stroke, and other complications is higher than for those with normal or elevated pressure.
Treatment typically starts with lifestyle modifications. Your healthcare provider may also recommend medication, particularly if you have other cardiovascular risk factors (diabetes, existing heart disease, chronic kidney disease) or if lifestyle changes don't bring your pressure down within a few months.
High Blood Pressure Stage 2
140/90 mmHg or higher
Stage 2 hypertension is more serious and typically requires treatment with both lifestyle changes and medication. At these levels, the force of blood against artery walls is causing ongoing damage to blood vessels, heart, kidneys, brain, and other organs.
Most people with Stage 2 hypertension need at least one blood pressure medication, and many require two or more medications working together. Regular monitoring and follow-up with your healthcare provider are essential to ensure treatment is working effectively.
Hypertensive Crisis
Higher than 180/120 mmHg
A hypertensive crisis is a medical emergency. Blood pressure at this level can cause immediate damage to organs including the brain, heart, kidneys, and eyes. If you get a reading this high, wait five minutes and measure again to confirm.
If your blood pressure remains above 180/120 mmHg:
- Without symptoms: Contact your healthcare provider immediately (hypertensive urgency)
- With symptoms (severe headache, chest pain, shortness of breath, vision changes, confusion, numbness): Call 911 immediately (hypertensive emergency)
Understanding Your Category
Your category is determined by whichever number—systolic or diastolic—places you in the higher category. For example, a reading of 135/75 would be classified as Stage 1 hypertension because the systolic (135) falls in that range, even though the diastolic (75) is normal.
This approach recognizes that both numbers matter for cardiovascular risk. Historically, diastolic pressure received more attention, but research has shown that elevated systolic pressure is actually a stronger predictor of cardiovascular events, particularly in adults over 50.
Isolated Systolic Hypertension
Some people—especially older adults—have elevated systolic pressure with normal or even low diastolic pressure. This pattern, called isolated systolic hypertension, results from arterial stiffening that comes with age. It carries the same cardiovascular risks as regular hypertension and requires the same attention.
Single Readings vs. Patterns
A single blood pressure reading doesn't tell the whole story. Blood pressure fluctuates throughout the day based on activity, stress, caffeine, and many other factors. A diagnosis of hypertension requires elevated readings on multiple occasions—typically at least two or three readings taken on different days.
Home monitoring provides a more complete picture than occasional office visits. Tracking your blood pressure over time reveals patterns and helps distinguish true hypertension from situational elevations like white coat hypertension (elevated readings only in medical settings).
Taking Action Based on Your Range
| Category | Systolic | Diastolic | Recommended Action |
|---|---|---|---|
| Normal | <120 | <80 | Maintain healthy lifestyle; recheck in 1-2 years |
| Elevated | 120-129 | <80 | Lifestyle changes; recheck in 3-6 months |
| Stage 1 | 130-139 | 80-89 | Lifestyle changes; consider medication; recheck in 1-3 months |
| Stage 2 | ≥140 | ≥90 | Lifestyle changes + medication; follow up in 1 month |
| Crisis | >180 | >120 | Immediate medical attention required |
Frequently Asked Questions
What do the two numbers in blood pressure readings mean?
The top number (systolic) measures pressure when your heart beats and pumps blood. The bottom number (diastolic) measures pressure when your heart rests between beats. Both numbers are important—elevation in either indicates increased cardiovascular risk.
Which number is more important?
Both matter, but systolic pressure is often considered more critical, especially in people over 50. Systolic pressure tends to rise with age as arteries stiffen, and elevated systolic is strongly associated with stroke and heart attack risk. However, elevated diastolic pressure is also significant, particularly in younger adults.
Why did the guidelines change in 2017?
The American College of Cardiology and American Heart Association updated guidelines in 2017, lowering the threshold for high blood pressure from 140/90 to 130/80 mmHg. Research showed that cardiovascular risk begins increasing at lower levels than previously recognized. The new guidelines aim to encourage earlier intervention.
Can blood pressure be too low?
Yes, but unlike high blood pressure, low blood pressure is primarily concerning when it causes symptoms. Readings below 90/60 mmHg with symptoms like dizziness, fainting, or fatigue warrant evaluation. Some people naturally run low without problems—for them, low readings indicate cardiovascular efficiency.
How often should I check my blood pressure?
Adults with normal blood pressure should check at least annually. Those with elevated or high blood pressure need more frequent monitoring—home monitoring several times per week is often recommended. Your healthcare provider can advise on the appropriate frequency for your situation.