Blood Pressure ChartUnderstanding Your Numbers
A blood pressure reading might seem like just two numbers separated by a slash, but these figures reveal crucial information about your cardiovascular health. When a nurse or doctor announces "120 over 80," they're telling you about the two distinct forces your blood exerts on your artery walls—one when your heart beats, another when it rests between beats.
Understanding what these numbers mean, where they fall on the blood pressure spectrum, and what actions they call for empowers you to take control of your health. The categories outlined here follow guidelines from the American Heart Association (AHA)1, which updated its definitions in 2017 based on extensive research linking lower blood pressure thresholds to better health outcomes.
How to Read Your Blood Pressure Numbers
Blood pressure is recorded as two numbers: systolic pressure (the top number) and diastolic pressure (the bottom number). Systolic pressure measures the force against your artery walls when your heart contracts and pumps blood out. This is the higher of the two numbers because the pumping action creates maximum pressure. Diastolic pressure, the lower number, measures the pressure when your heart relaxes between beats and refills with blood.
The measurement is expressed in millimeters of mercury (mmHg), a unit that dates back to early blood pressure devices that used mercury columns. A reading of 120/80 mmHg means your systolic pressure is 120 mmHg and your diastolic is 80 mmHg.
Both numbers matter. While medical guidance has sometimes emphasized one over the other depending on age and circumstances, current understanding recognizes that elevated readings in either number can indicate cardiovascular risk and may warrant attention or treatment.
Blood Pressure Categories
Blood pressure exists on a continuum, but medical guidelines divide it into categories that help guide decisions about monitoring and treatment. The category boundaries aren't arbitrary—they reflect research showing increased health risks at certain thresholds.
An important principle: your category is determined by whichever number—systolic or diastolic—places you in the higher category. For example, if your systolic is 118 (normal) but your diastolic is 85 (Stage 1 hypertension), you're classified in Stage 1 hypertension. You only need to meet one criterion, not both.
| Blood Pressure Category | Systolic (mmHg) | Diastolic (mmHg) |
|---|---|---|
| Normal | Less than 120 | Less than 80 |
| Elevated | 120-129 | Less than 80 |
| High Blood Pressure (Stage 1) | 130-139 | 80-89 |
| High Blood Pressure (Stage 2) | 140 or higher | 90 or higher |
| Hypertensive Crisis | Higher than 180 | Higher than 120 |
Normal Blood Pressure: Below 120/80 mmHg
Normal blood pressure represents the ideal state where your cardiovascular system operates without excessive strain. Blood flows freely through arteries that aren't under undue pressure, and your heart doesn't have to work harder than necessary to circulate blood throughout your body.
Having normal blood pressure doesn't mean you can ignore cardiovascular health—it means your current state is healthy and worth maintaining. The lifestyle habits that keep blood pressure normal now also protect against future increases: regular physical activity, a balanced diet low in sodium, maintaining a healthy weight, limiting alcohol, and avoiding tobacco.
People with normal blood pressure should continue monitoring periodically. Blood pressure tends to rise with age, and catching increases early provides more options for addressing them through lifestyle modifications alone.
Elevated Blood Pressure: 120-129/<80 mmHg
Elevated blood pressure serves as an early warning signal. Your systolic pressure has crept above the normal range, but your diastolic remains healthy. This pattern often indicates that blood pressure is beginning to rise—a trend that, left unaddressed, frequently progresses to hypertension.
At this stage, medication isn't typically recommended. Instead, the focus is on lifestyle modifications that can bring blood pressure back to normal. Reducing sodium intake, increasing physical activity, losing excess weight, and managing stress can all help. Many people at this stage can return to normal blood pressure through these changes alone.
The elevated category was introduced in the 2017 guidelines specifically to identify people who would benefit from early intervention. About 37% of people with elevated blood pressure develop hypertension within four years if no action is taken, but proactive lifestyle changes can significantly reduce this risk.
Stage 1 Hypertension: 130-139/80-89 mmHg
Stage 1 hypertension marks the beginning of high blood pressure as a medical diagnosis. This category includes millions of adults who may not realize their blood pressure has reached a level requiring attention—blood pressure at this level rarely causes noticeable symptoms.
Treatment at Stage 1 depends on your overall cardiovascular risk profile. For people without other risk factors (diabetes, kidney disease, previous heart attack or stroke, or high calculated cardiovascular risk), doctors often recommend a three-to-six-month trial of lifestyle changes before considering medication. Dietary improvements, increased exercise, and weight loss can lower blood pressure by 10-20 mmHg or more in some individuals—enough to bring Stage 1 readings back to normal or elevated ranges.
For those with additional cardiovascular risk factors, medication may be recommended alongside lifestyle changes from the start. The combination approach addresses blood pressure more aggressively in people who face greater potential consequences from uncontrolled hypertension.
Stage 2 Hypertension: 140/90 mmHg or Higher
Stage 2 hypertension represents definitively high blood pressure that typically requires medication in addition to lifestyle modifications. At these levels, the force against your artery walls is causing ongoing damage—accelerating atherosclerosis, straining your heart, and potentially harming your kidneys, eyes, and brain.
Most people with Stage 2 hypertension need two or more blood pressure medications to reach their goals. This isn't a failure—it reflects the reality that blood pressure is controlled by multiple body systems, and targeting several simultaneously often works better than maximizing a single medication.
The urgency of treatment increases as numbers rise. Someone with blood pressure of 160/100 faces greater immediate risk than someone at 142/92, though both require attention. Your doctor will help determine the appropriate intensity of treatment based on your specific numbers and overall health picture.
Hypertensive Crisis: Above 180/120 mmHg
Hypertensive crisis represents a medical emergency. Blood pressure at these levels can cause immediate damage to organs—stroke, heart attack, kidney failure, or aortic dissection (a tear in the body's main artery) can occur within hours or even minutes.
If you measure blood pressure this high, wait five minutes and measure again to confirm. If the reading remains above 180/120, seek medical attention immediately. Don't wait to see if it comes down on its own.
Hypertensive emergencies are distinguished from hypertensive urgencies by the presence of organ damage. Both require prompt medical evaluation, but emergencies—those with symptoms like chest pain, shortness of breath, severe headache, vision changes, or confusion—typically require immediate hospitalization and intravenous medications to lower blood pressure quickly and safely.
Factors That Affect Blood Pressure
Blood pressure isn't a fixed characteristic—it fluctuates throughout the day and varies based on numerous factors. Understanding these influences helps you interpret your readings and take appropriate action.
Age and Arterial Changes
Blood pressure typically rises with age as arteries lose elasticity and become stiffer. This natural stiffening means the heart must pump against greater resistance, raising systolic pressure in particular. By age 65, more than half of adults have hypertension. However, this age-related increase isn't entirely inevitable—populations with lifelong healthy habits show much smaller increases.
Diet and Sodium
What you eat directly affects blood pressure. Sodium causes your body to retain fluid, increasing blood volume and pressure. Most people consume far more sodium than the recommended 2,300 mg daily limit, much of it hidden in processed and restaurant foods. Conversely, potassium helps your kidneys excrete sodium and relaxes blood vessel walls, making potassium-rich foods beneficial.
Physical Activity
Regular exercise strengthens your heart, allowing it to pump blood more efficiently with less effort. Active people typically have lower resting blood pressure than sedentary individuals. Exercise can lower blood pressure by 5-8 mmHg, and the benefits accumulate with consistent activity over time.
Weight
Excess weight increases the work your heart must do to supply blood to your body. Fat tissue also produces hormones that can raise blood pressure. Losing even 5-10 pounds can produce measurable blood pressure reductions. For every kilogram of weight lost, blood pressure typically drops about 1 mmHg.
Stress and Sleep
Acute stress causes temporary blood pressure spikes through hormone release and nervous system activation. Chronic stress may contribute to sustained elevation through ongoing hormonal effects and stress-related behaviors (poor diet, reduced exercise, increased alcohol). Poor sleep—particularly sleep apnea—is strongly associated with hypertension.
Genetics and Family History
If your parents or siblings have high blood pressure, you're more likely to develop it yourself. Genetic factors influence how your body handles sodium, how your blood vessels respond to various signals, and how likely you are to develop arterial stiffness. However, genetics aren't destiny—lifestyle choices can often overcome genetic predisposition.
Medications and Substances
Various medications can raise blood pressure, including NSAIDs (like ibuprofen), decongestants, some antidepressants, oral contraceptives, and steroids. Caffeine causes temporary spikes, while alcohol raises blood pressure when consumed excessively. Illegal stimulants like cocaine and methamphetamine can cause dangerous blood pressure elevations.
Taking Action Based on Your Numbers
Normal (below 120/80): Maintain your healthy habits. Continue regular monitoring to catch any changes early. No specific treatment needed.
Elevated (120-129/<80): Focus on lifestyle modifications—reduce sodium, increase exercise, manage weight and stress. Recheck blood pressure in 3-6 months to assess whether changes are working.
Stage 1 (130-139/80-89): Discuss with your healthcare provider. Without other risk factors, you may try lifestyle changes first. With additional risks, medication may be recommended alongside lifestyle modifications.
Stage 2 (140/90 or higher): Consult your healthcare provider promptly. Medication is typically needed, often in combination with lifestyle changes. Regular monitoring and follow-up are essential.
Hypertensive Crisis (above 180/120): This is urgent. Confirm the reading, then seek immediate medical attention. If you have symptoms like chest pain, severe headache, or shortness of breath, call emergency services.
Frequently Asked Questions
Why did the blood pressure guidelines change in 2017?
The American Heart Association and American College of Cardiology lowered the threshold for high blood pressure from 140/90 to 130/80 based on research showing that cardiovascular risk begins increasing at lower levels than previously recognized. Studies found that people with blood pressure in the 130-139/80-89 range had approximately double the cardiovascular risk of those with normal blood pressure. The change aims to encourage earlier intervention when it can be most effective.
My blood pressure varies a lot—which reading should I trust?
Blood pressure naturally fluctuates throughout the day and in response to activity, stress, and other factors. A single reading is just a snapshot. For accurate assessment, measure at the same time daily under consistent conditions, take multiple readings a minute apart, and average them. A pattern of elevated readings matters more than any single measurement. Your doctor may recommend 24-hour ambulatory monitoring or a week of home readings for a complete picture.
Is white coat hypertension real?
Yes. White coat hypertension—elevated readings in medical settings but normal readings elsewhere—affects 15-30% of people diagnosed with hypertension. The stress of being in a medical environment can genuinely raise blood pressure. Home monitoring often provides more representative readings and helps distinguish white coat effects from true hypertension. However, white coat hypertension isn't entirely benign—it may indicate increased cardiovascular risk compared to people with normal readings everywhere.
Can blood pressure be too low?
Yes, though it's less common than high blood pressure being a problem. Blood pressure below 90/60 is generally considered low, but what matters more is whether you have symptoms—dizziness, fainting, fatigue, or difficulty concentrating. Some people have naturally low blood pressure without any problems. Low blood pressure becomes concerning when it causes symptoms or drops suddenly, which could indicate dehydration, blood loss, heart problems, or medication effects.
How often should I check my blood pressure?
Adults with normal blood pressure should have it checked at least once a year during routine healthcare visits. Those with elevated readings or hypertension may need more frequent monitoring—often daily home measurements, at least initially. Home monitoring provides valuable information between doctor visits and helps track the effects of lifestyle changes or medications. Your healthcare provider can recommend an appropriate monitoring schedule for your situation.
Source: Guidelines from the American Heart Association (AHA) and American College of Cardiology (ACC), updated 2017. These guidelines are reviewed periodically to incorporate new research findings.
1 Blood pressure guidelines have evolved over time based on extensive medical research. The current categories were updated in 2017 when the AHA and the American College of Cardiology (ACC) lowered the threshold for high blood pressure to 130/80 mmHg from the previous 140/90 mmHg. This change was made to encourage earlier intervention and prevent heart disease. ↩