The Best Time to Take Your Blood Pressure

The best time to take your blood pressure depends on a few factors. If you have high blood pressure (hypertension), your healthcare provider may ask you to monitor your blood pressure twice a day—once in the morning and once in the evening.

Some healthcare providers recommend checking your blood pressure first thing in the morning, after emptying your bladder but before taking medication or having your morning coffee.

Blood pressure fluctuates throughout the day. It follows a circadian rhythm, rising sharply upon awakening, peaking in the afternoon, then declining in the evening. Self-measured blood pressure monitoring should be done at consistent times each day.

This article discusses the best time to take your blood pressure. It explains how blood pressure changes throughout the day and provides tips for getting the most accurate readings.

When to Take Your Blood Pressure

At-home self-monitoring of blood pressure should be done twice a day, as directed by your healthcare provider. Avoid caffeine, alcohol, smoking, or exercise for 30 minutes prior to taking your blood pressure.

Ideally, you want to take your blood pressure at the same set times each day. This is because blood pressure varies by up to 30% in a day. Routinely checking at the same time each day will provide the most accurate picture.

In the Morning

Many healthcare providers recommend taking your blood pressure first thing in the morning. Blood pressure is typically at its lowest while you sleep, then rises as you wake up and start moving for the day.

Morning blood pressure readings should be taken after emptying your bladder but before taking blood pressure medication or drinking coffee. After using the bathroom, sit quietly for 5 minutes. Avoid potential stressors, such as checking work emails or watching the news, that may raise your blood pressure.

To ensure accurate results, take two readings roughly one minute apart. If you get two vastly different readings, wait another minute and take it again.

In the Afternoon

Blood pressure rises as the day goes on and typically is at its highest for the day in the afternoon. In most cases, healthcare providers do not recommend taking afternoon readings. However, some researchers think afternoon readings can provide valuable insight.

According to a 2020 study published in the Journal of Clinical Hypertension, blood pressure peaks for the day between 4 p.m. and 6 p.m. The study authors found testing during this window can help to identify people at risk for a form of heart disease known as left ventricular hypertrophy.

Blood pressure peaks vary from person to person. To pinpoint your unique patterns, your cardiologist may recommend a 24-hour ambulatory blood pressure monitoring test. This involves wearing a small device that tracks your blood pressure as you go about your daily activities.

In the Evening

Evening blood pressure readings are commonly used alongside morning readings. The best time to take your blood pressure in the evening is still up for debate. Home blood pressure monitoring guidelines are different across the globe.

In the United States, the current guidelines advise checking your blood pressure before your evening meal. In Asia, evening blood pressure readings are recommended before bed, after dinner and bathing. European guidelines are less specific and simply say in the evening. Researchers are uncertain if this is due to cultural variations or genetic factors among different ethnicities.

Ask your healthcare provider to clarify the best time for you to take your blood pressure.

Advantages of Home Blood Pressure Monitoring

Research has shown that home blood pressure readings are similar to measurements recorded by 24-hour ambulatory monitors. These monitors are the gold standard for predicting a person's risk for heart disease. 

Home blood pressure readings may eliminate the white-coat effect. The phrase describes how a person's blood pressure may rise when they visit their healthcare provider's office. It is very common.

Your healthcare provider may recommend home blood pressure checks for other reasons besides careful monitoring for high blood pressure. For instance, they may want to see whether a drug used to control blood pressure is working. Or they may want to look for any changes if you adopt a new low-salt diet. 

They may use home blood pressure checks to monitor for low blood pressure in certain people. It also may be useful to monitor for masked hypertension. This happens when your blood pressure is normal at your healthcare provider's office, but it is higher at home.

Interpreting Your Blood Pressure Readings

Blood pressure measurements are given as two numbers. They are the systolic (top) number and diastolic (bottom) number. This is measured in millimeters of mercury (mm Hg). So a blood pressure of 120/80 mm Hg is read as "120 over 80."

According to the American Heart Association, there are five blood pressure categories:

Your healthcare provider will use your home blood pressure readings alongside the office blood pressure readings. They are not meant as a substitute, so be sure to continue seeing your provider for regular checkups.

Tips for Taking Your Blood Pressure 

Home blood pressure monitoring allows your healthcare team to compare one relatively steady measurement to another over time.

Digital at-home blood pressure monitors are easy to use and sold at most drug stores. The most important factor in selecting one is the cuff size. Blood pressure cuffs range in size from a child's small to an adult extra-large. Your healthcare provider can guide you to the appropriate device for you.

Follow these tips so that you get more accurate results when testing at home:

• Get readings at least twice a day. Blood pressure changes throughout the day. Your blood pressure is typically at its lowest right after waking up. It tends to vary by up to 30% across the day. This is because of hormone changes, activity levels, and eating.
• Measure at the same times every day. The same timing should give you about the same reading, except for other influences like exercise. For example, your routine for checking your blood pressure may be to take two to three checks both in the morning and at night.
• Take more than one reading each time you check. Try to get two or three readings, one minute apart, each time you check your blood pressure. Record the results in a written log or online tracker.
• Prepare 30 minutes ahead of readings. Do not exercise, smoke, drink caffeine, or eat a big meal for 30 minutes before you take a reading. All of these can lead to elevated readings. You should also empty your bladder and give yourself at least five minutes of quiet rest time before taking your blood pressure. 
• Pick a convenient time. Make sure that your blood pressure checks work within your schedule. Choose a time slot that is unlikely to be disrupted by work or other conflicts. If you work outside of your home, you may want to take your blood pressure before work or when you return.
• Sit in a chair. If you take your blood pressure while standing up, it can lead to a higher or inaccurate reading. Sit comfortably in a chair with your back supported. Rest your arms on a table or other flat surface, and place your feet flat on the floor.

Summary

At-home blood pressure monitoring is typically done twice a day, at the same time each day. Your healthcare provider will let you know the best time to check your blood pressure and how to document it.

Morning blood pressure readings should be taken when you first wake up, after using the bathroom, but before drinking coffee or taking medication.

Afternoon blood pressure readings are not commonly recommended. When they are, it is commonly done in the late afternoon between 4 p.m. and 6 p.m.

Evening blood pressure readings may be taken before your evening meal or before bed, depending on your cardiologist's recommendations.

Blood pressure should be checked while seated after a few minutes of rest. Take at least two readings a minute apart each time. Wait at least 30 minutes after having caffeine, alcohol, smoking, or exercising before taking your blood pressure.