Blood pressure refers to the amount of pressure there is when blood pushes against your artery walls. When you or a healthcare provider takes your blood pressure, you can check what the reading means using a blood pressure chart.
A blood pressure chart lists the five stages of blood pressure—from normal to a hypertensive crisis—and the range of blood pressure that falls into each category.
Measuring your blood pressure and evaluating it using a blood pressure chart can give you important information about your health, such as your risk of complications like heart disease and stroke.
How to Read a Blood Pressure Chart
The American Heart Association (AHA) and American College of Cardiology (ACC) provide the following blood pressure chart for adults:
|Blood Pressure Category||Systolic Blood Pressure (mmHg)||and/or||Diastolic Blood Pressure (mmHg)|
|Normal||Below 120||and||Below 80|
|Hypertension Stage 1||130-139||or||80-89|
|Hypertension Stage 2||140+||or||90+|
When you measure your blood pressure, you will receive two numbers. These numbers are measured in millimeters of mercury (mmHg).
The number on top, or the first number, is your systolic blood pressure. This is your blood pressure at its highest when your heart beats.
The bottom number, or the second number, is your diastolic blood pressure. This is the force of your blood against your arteries at its lowest, in between heartbeats.
A blood pressure chart includes ranges for both systolic and diastolic blood pressure. These ranges correspond to the blood pressure categories that are also in the chart. There are five categories of blood pressure readings:
- Normal: Continue doing activities and eating foods that are considered heart-healthy.
- Elevated: Unless you take preventative steps, you’re likely to develop high blood pressure.
- Hypertension stage 1: A healthcare provider will likely tell you to make lifestyle changes and may prescribe blood pressure medication.
- Hypertension stage 2: You will likely be prescribed both lifestyle changes and medication.
- Hypertensive crisis: You have a sudden increase in blood pressure that is considered a medical emergency.
Depending on where in the chart your systolic and diastolic blood pressure fall is what blood pressure category you’d be considered to have.
Normal Blood Pressure Levels by Age
The standard blood pressure chart is a good tool for adults to figure out whether their blood pressure is considered normal. But healthy blood pressure levels vary by age and sex. That means special considerations may need to be taken when looking at the standard adult chart.
Healthcare providers may use a different blood pressure chart altogether to determine whether a child has a healthy blood pressure.
Blood Pressure Levels for Children
Blood pressure readings for children vary based on factors like size and age.
To determine whether a child’s blood pressure levels are normal, a healthcare provider will typically use a blood pressure chart that takes into account children’s height, age, and sex. These pediatric blood pressure charts are rows and rows, columns and columns long because of how widely varying normal blood pressure is for each year and height.
Children 12 or younger who have blood pressure below the 90th percentile for their age and height are considered to have normal blood pressure. Children 13 or up follow the same blood pressure thresholds as adults, meaning a systolic blood pressure below 120mmHg and a diastolic blood pressure below 80mmHg is considered normal.
Blood Pressure Levels for Adults
Based on the blood pressure chart from the AHA and ACC, normal blood pressure for adults is a systolic blood pressure below 120mmHg and a diastolic blood pressure below 80mmHg.
However, average systolic and diastolic blood pressure levels can vary by sex. For instance, one study showed that the normal threshold for systolic blood pressure among women might actually be 110mmHg. Once systolic blood pressure hit 110mmHg, the researchers saw an association with the development of cardiovascular diseases like heart attack.
Your healthcare provider can advise whether you should follow the standard chart’s guidance or use slightly adjusted classifications.
Blood Pressure Levels for Older Adults
The standard blood pressure chart from the AHA and ACC applies to adults of all ages, including older adults.
However, it’s common for adults’ blood pressure levels to change over the years. Many older adults have a systolic blood pressure of 130mmHg or higher and a diastolic blood pressure under 80mmHg. This reading is known as isolated systolic hypertension. If left untreated, isolated systolic hypertension can lead to symptoms like dizziness, shortness of breath, and falling.
How Is Blood Pressure Measured?
Blood pressure can be measured at a doctor’s office or with an at-home blood pressure monitor.
Usually, this involves wrapping an inflatable cuff around your arm just above the elbow. As the cuff inflates, a gauge measures your systolic and diastolic blood pressure. Your healthcare provider may also use a stethoscope to measure your pulse. Most digital blood pressure monitors will also take your pulse.
To make sure you get the most accurate results possible, follow these tips:
- Don’t take your blood pressure soon after drinking alcohol or caffeine, exercising, or smoking.
- Don’t take your blood pressure when you are anxious.
- Sit on a chair with your feet planted firmly on the floor and your arm resting on a flat surface. Your upper arm should be at the level of your heart.
- Take your blood pressure at the same time each day.
- Don’t place the blood pressure cuff over your clothing.
- Take several blood pressure readings, not just one.
Low Blood Pressure
Low blood pressure, also known as hypotension, is defined as a blood pressure reading below 90/60mmHg for most adults. Low blood pressure is not included on the standard blood pressure chart, but it is still a good threshold to know. If your blood pressure is low, it means that blood is flowing through your blood vessels at a lower pressure than it should be.
There are many potential reasons for low blood pressure, including:
- Bed rest
- Blood loss
- Certain medications
- Anaphylaxis (severe allergic reaction)
- Certain heart problems
- Problems with the endocrine system, such as hypothyroidism (underactive thyroid)
- Low levels of iron, folate, or vitamin B-12
- Septic shock (a severe response to an infection)
If you have just one or two low blood pressure readings, it’s typically not a problem. However, you should see a healthcare provider if you experience any symptoms of low blood pressure, such as:
- Difficulty concentrating
- Blurry vision
- Clammy, cold skin
- Difficulty breathing
- Fainting (syncope)
High Blood Pressure
High blood pressure, or hypertension, refers to systolic blood pressure that is consistently above 130mmHg or diastolic blood pressure that remains above 80mmHg.
Sometimes certain medications like steroids or estrogen-containing birth control pills or certain conditions like lupus or thyroid problems can cause hypertension. Once the medication is stopped or the condition treated, the blood pressure improves.
Most often, though, blood pressure develops over time. Risk factors for high blood pressure include:
- High salt intake
- Lack of exercise
- Excessive alcohol intake
- Lack of good-quality sleep
- Older age
- Excessive caffeine intake
Over time, untreated high blood pressure can lead to a number of potential health complications, such as:
- Heart attack
- Heart failure
- Kidney disease
- Kidney failure
- Low libido
- Heart disease
- Vision problems
When to See a Healthcare Provider
If you notice consistently high readings when you monitor your blood pressure at home, reach out to a healthcare provider. They may recommend that you make lifestyle changes or prescribe medication to lower your blood pressure.
If your blood pressure reaches 180/120mmHg or higher more than once within a period of five or more minutes and you have any additional signs of a hypertensive crisis, seek immediate medical care. Symptoms of a hypertensive crisis include:
- Chest pain
- Difficulty breathing
- Back pain
- Muscle weakness
- Vision problems
- Difficulty speaking
A Quick Review
A blood pressure chart is a helpful tool when trying to see what your blood pressure reading means. The American Heart Association and American College of Cardiology developed a blood pressure chart that adults can use as a reference when measuring their blood pressure at a healthcare office or home. The chart offers ranges of systolic and diastolic blood pressure and their corresponding blood pressure classifications: normal, elevated, hypertension stages 1 and 2, and hypertensive crisis. Based on the chart, normal blood pressure for adults is below 120/80mmHg. Children have different blood pressure charts.
The chart alone cannot diagnose high or low blood pressure. But monitoring your blood pressure and consulting a blood pressure chart can help you protect your health. If your blood pressure levels are too high or too low, ask a healthcare provider about potential treatment options and lifestyle changes.
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