We’ve all heard that blood pressure is an important part of our overall health. But do you know what normal blood pressure should be or how to tell if your blood pressure is elevated or too high?

Your blood pressure numbers mean a lot for your heart’s health. If your blood pressure is high, it means your heart is working too hard and the force of the blood flowing through your vessels is very high. This increased pressure can cause your arteries to thicken or harden and your blood vessels to weaken. High blood pressure increases your risk for a range of medical conditions

High blood pressure (also called hypertension) is incredibly common. About half of adults have high blood pressure, but only one in four have it under control, according to the Centers for Disease Control and Prevention (CDC). Many people don’t even know that they have high blood pressure, since the only way to know if you have it is to get a blood pressure screening.

Keep reading to learn what’s considered normal, elevated or high blood pressure, and why it’s more common as you age and how to get tested.

What does blood pressure tell you? It measures how well your heart works

The heart is good at performing under pressure. It consistently pumps blood throughout your blood vessels, providing every part of your body the oxygen you need to live. Blood pressure measures the force of your blood pushing against the walls of your blood vessels.

What the blood pressure numbers mean and how to read them

Blood pressure readings have two numbers, which are read as one number “over” the other. These numbers show the highest and lowest levels of pressure in your arteries during the blood pressure reading. For example: 110/70 mm Hg.

Blood pressure is measured in mm Hg, which stands for millimeters of mercury. This is because the first blood pressure devices used mercury to measure the pressure of the blood. Even though mercury is no longer used in modern devices, the unit of mm Hg is still a standard for measuring pressure of all kinds.

Systolic blood pressure: What the top number means

The top number of your reading is called systolic blood pressure. It tells you the force of the blood against artery walls when your heart beats. Your blood pressure is highest during your heartbeat. So, the systolic number measures the maximum pressure in your arteries at the time of the reading.

Diastolic blood pressure: What the bottom number means

The bottom number is called diastolic blood pressure. It tells you what your blood pressure is when your heart is at rest between heartbeats. Your blood pressure is lowest when your heart is at rest, meaning the diastolic number is the lowest pressure in the arteries during the reading.

How blood pressure numbers are used together

Taken together, your systolic and diastolic blood pressure numbers give you and your doctor an idea of how much pressure is in your arteries when your heart is pumping and at rest. There’s often a strong relationship between the types of blood pressure. For example, if you have high systolic numbers, you’re more likely to have high diastolic numbers, too.

If one or both of your blood pressure numbers are too high, you may have elevated or high blood pressure; if one or both numbers are too low, you may have low blood pressure. While both numbers are important, doctors are sometimes more concerned with systolic blood pressure, especially if your numbers are high.

Of course, blood pressure can change from day to day, and even from hour to hour. Your doctor will compare multiple blood pressure readings when considering your heart health.

How is high blood pressure diagnosed?

High blood pressure is usually diagnosed by a health care professional after a blood pressure screening during an annual checkup. If your blood pressure is usually normal, one high reading is likely nothing to worry about.

Blood pressure can be temporarily raised by lots of different things – such as physical activity, dehydration, what you eat or drink, and the temperature outside. Even just being in the doctor’s office can raise blood pressure.

So before diagnosing high blood pressure, your doctor will likely look at past readings and possibly take another reading. If they’re still not sure, they may recommend additional testing with a home blood pressure monitoring system. And depending on your risk factors or other health conditions, you may be referred to a cardiologist who specializes in cardiovascular diseases (heart-related conditions).

Blood pressure chart: Understanding blood pressure ranges

The following chart is based on recommendations from the American Heart Association. You can use it to see if your blood pressure is normal or too high. Sometimes, both your systolic and diastolic numbers need to be at certain levels to fall into a blood pressure range. At other times, only one or the other number needs to be within a certain range.

Blood pressure ranges for adults: What’s normal and what’s not

Blood pressure categories and what they mean

Blood pressure readings are classified into different categories, each with their own meaning and potential health concerns.

Normal blood pressure range

A normal blood pressure is at or under 120 systolic over 80 diastolic. If your blood pressure reading is at or under 120 over 80, you have healthy blood pressure. However, blood pressure can change as you get older (more on that later), so it’s important to have healthy habits to help manage blood pressure you age.

Elevated blood pressure range

If a reading is between 120-129 systolic and less than 80 diastolic, it’s considered elevated. If you consistently have readings within this range, it means you’re likely to develop high blood pressure unless you make lifestyle changes to help lower your blood pressure and reduce your risks of heart disease.

High blood pressure range

If your readings are consistently at or above 130 over 80, you have high blood pressure. High blood pressure (also called hypertension) is divided into two stages of severity:

• Stage 1 hypertension – 130-139 systolic or 80-89 diastolic
• Stage 2 hypertension – 140 or higher systolic or 90 or higher diastolic

If you have high blood pressure, it means your blood is pushing too strongly through your body. High blood pressure increases your risk for a range of medical conditions, which is why managing your blood pressure is so important. If you have high blood pressure, making healthy lifestyle choices can help you lower blood pressure. Also talk to your doctor to see if medications may be a good choice for you.

A hypertensive crisis can happen if your blood pressure is too high

If you have a blood pressure reading that is above 180 in the top number or above 120 in the bottom number, you may be having a hypertensive crisis, which is a medical emergency. Blood pressure this high can damage your blood vessels and could lead to a stroke.

Here’s what to do: Wait five minutes and retest your blood pressure to confirm that the reading is accurate. If your numbers are just as high, call 911 immediately.

It’s also possible to have blood pressure that’s too low

In most cases, the lower your blood pressure, the better. But it’s possible that You may have low blood pressure if your readings are lower than 90 systolic mm Hg and 60 diastolic mm Hg.

Low blood pressure can be okay in some people, without any noticeable symptoms. But it can also be a sign of dehydration or medical conditions, and sudden drops in blood pressure can be dangerous. Talk to your doctor if your blood pressure readings are consistently low. If low blood pressure comes with sudden vision changes, dizziness, fainting, fatigue or nausea, seek emergency medical care.

Your chance of high blood pressure goes up as you get older

High blood pressure is something that can affect your heart range at any age. But it becomes more likely as you get older because arteries aren’t as effective at pumping blood through the body. Arteries naturally get stiffer as you age, and plaque builds up on the insides of blood vessels. These changes make your heart work harder to pump blood through your body, and this increases the pressure in your arteries.

It's likely that your blood pressure will go up as you get older, even if you eat a heart-healthy diet and exercise to strengthen your heart. But a healthy lifestyle is still one of the best ways to keep your heart (and the rest of you) as healthy as possible.

That’s why it’s so important to start building good habits and taking steps to lower blood pressure in your 40s and 50s, especially if your blood pressure numbers fall into an elevated range.

Adult blood pressure chart by age and gender

As you get older, there are differences in normal blood pressure for women and men. But it’s typical for an adult’s blood pressure to be elevated between 40 and 59 years old, and high after age 60.

While uncommon, children can have high blood pressure, too

You usually don’t need to worry about blood pressure in children. But it’s possible for children to have high blood pressure, and it’s more likely in kids who are very overweight or in their teens.

If you’re worried about your child’s blood pressure, talk to their doctor. At HealthPartners, we use a program called TeenBP to identify children with high blood pressure, earlier.

Causes of high blood pressure

Most of the time there’s no obvious cause for high blood pressure. Genetics (such as a family history of heart disease), age and ethnicity can all play a role. High blood pressure can also be a complication of pregnancy. But in as many as 95% of reported cases, doctors can’t find a direct underlying cause.

Other risk factors that can contribute to high blood pressure include:

• Smoking
• Being overweight or obese
• Not exercising enough
• A diet that includes too many fatty foods and too much salt
• Drinking more than 1 to 2 alcoholic beverages per day
• Kidney disease
• Adrenal and thyroid disorders
• Sleep apnea

What does high blood pressure feel like? Usually nothing

High blood pressure often doesn't have any symptoms, so you usually don't feel it. That’s why it’s important to stay up to date on your preventive care screenings, which can help identify potential problems like elevated blood pressure when it’s easiest to treat.

If your blood pressure reaches extremely high levels, you may get a headache, shortness of breath or a nosebleed. However, these symptoms may not be specific to your blood pressure. Critically high blood pressure can be caused by conditions that can have similar symptoms, like strokes, heart attacks, heart failure, kidney failure or certain drug interactions.

How to check your blood pressure: Testing at the clinic or at home

A blood pressure check is a common screening for heart health. Chances are your doctor checked it during your last appointment. If it’s been a while since you’ve seen your primary care doctor, make an appointment for a preventive care visit. But if you just want to get your blood pressure checked, you can make a separate appointment for that.

Another option is to purchase an at-home blood pressure monitor. Having your own monitor can be helpful since you can test your blood pressure more frequently or at different times of the day. Plus, many people’s blood pressure is higher than usual at the doctor’s office (this is called white coat hypertension), so measuring your blood pressure at home may provide more accurate readings.

Some pharmacies have in-store machines that you can use to check your blood pressure. But a home-based monitor tends to provide more accurate results than a store-based machine, so use a store-based monitor if it’s your only choice.

Choosing a home-based blood pressure monitor

There are many great home-based digital blood pressure monitors. A typical blood pressure monitor costs between $40 to $100, but your insurance may cover part or all of the cost.

When shopping for a monitor, look for one with a cuff that goes around your arm and that inflates by itself. Ideally, you’ll want a monitor that stores your blood pressure readings, or even better, collects the information in an app.

You can ask your doctor if they have recommendations. Or consider choosing a blood pressure monitor that is validated to meet the criteria of the American Medical Association.

If you purchase a home-based blood monitor, it can be a good idea to bring it to your next doctor’s appointment. This can be especially helpful if your readings in the doctor’s office are very different from the numbers you get at home. They’ll be able to make sure you’re using it correctly.

Lowering or managing your blood pressure: It starts with lifestyle changes

It’s always a great time to take steps to lower or manage blood pressure, such as changing what you eat, managing stress and exercising to strengthen your heart.

Choosing foods that lower blood pressure can have an especially big impact. A couple quick steps to get started are eating more fruits and veggies and less packaged foods (or opting for low sodium options when you do).

If you have normal or elevated blood pressure, making changes to your diet and lifestyle can keep your blood pressure numbers from climbing into unhealthy ranges.

If you have stage 1 or stage 2 high blood pressure, your doctor may also recommend blood pressure medication if you’re not able to get your blood pressure numbers to a healthy range with lifestyle changes and diet alone. But it will still be important to continue with heart-healthy habits.

Using a home-based blood monitor can be very helpful as you take steps to lower or manage your blood pressure. You’ll be able to see the impact of the changes that you make. And if your numbers aren’t headed the right way, you can let your doctor know. They’ll be able to provide recommendations to help get your numbers back on track.

Can high blood pressure be life threatening?

High blood pressure can be dangerous if it’s left untreated. It forces your heart to work harder to get blood out to the rest of your body, and can damage your blood vessels. It can also lead to a number of serious and potentially life-threatening conditions, including:

• Cardiovascular disease
• Heart failure
• Stroke
• Kidney disease

When to call 911 for high blood pressure

Call 911 immediately if you have extremely high blood pressure or are experiencing warning signs of a heart attack or stroke. Here’s what to watch for:

• Blood pressure reading of 180 over 120
• Severe chest pain
• Severe headache, accompanied by confusion and blurred vision
• Nausea
• Significant anxiety
• Shortness of breath
• Seizures

Take steps to reach and maintain healthy blood pressure numbers

Left untreated, hypertension puts you at higher risk of heart disease, stroke and other serious conditions. The good news is that there are many ways to lower blood pressure, and it all starts with knowing your blood pressure numbers.

Staying on top of your routine preventive care – specifically annual checkups with a primary care doctor – is one of the best ways to catch blood pressure issues and identify other risk factors or health conditions earlier, when they’re most treatable.

Also, don’t ignore out-of-the-ordinary symptoms. While high blood pressure often comes without symptoms, other heart-related issues could be at play. Don’t hesitate to get the care you need.