• A healthcare provider attaches the cuff and monitor to the patient.
• The device automatically takes blood pressure readings at pre-set intervals, often every 15 to 30 minutes during the day and at longer intervals at night.
• The patient wears the device continuously for 24 hours, including during sleep.
• A diary is often provided for the patient to record activities, sleep times, and any symptoms, which helps in interpreting the data.

• Provides a complete picture: It captures blood pressure variations throughout the day and night, unlike a single office visit.
• Eliminates the "white coat effect": It avoids the artificially high readings that can occur in a doctor's office due to anxiety.
• Diagnoses specific conditions: It is crucial for diagnosing masked hypertension, where blood pressure is normal in the clinic but high at home.
• Evaluates medication effectiveness: Doctors can use the data to see if medication is effectively controlling blood pressure throughout the entire day and night.
• Identifies nocturnal hypertension: It reveals if blood pressure remains high during sleep, which can be a risk factor for heart disease.

What is ambulatory blood pressure monitoring?

Ambulatory blood pressure monitoring is a way of measuring and managing high blood pressure. High blood pressure (hypertension) means your top number (systolic blood pressure) is at least 130 mmHg (millimeters of mercury), and/or your bottom number (diastolic blood pressure) is at least 80 mmHg.

Ambulatory blood pressure monitoring records your blood pressure (BP) readings over a 24-hour period, whether you're awake or asleep. This happens outside your healthcare provider's office, as you go about your daily life. You wear a cuff on your arm and a small device attached to a strap or belt.

You may be more familiar with having your BP checked in a healthcare provider's office during an appointment. In this case, your provider uses a device called a sphygmomanometer to measure and record one or two readings during your visit.

Ambulatory blood pressure monitoring takes dozens of readings over a continuous period. In most cases, the device records readings every 15 to 30 minutes during the day and every 60 minutes at night. The device also measures your heart rate (how fast your heart is beating). Your provider uses this data to calculate your average BP over the 24-hour period. They also calculate changes in BP and heart rate, BP distribution pattern and other statistics.

Healthcare providers use this method for many reasons, including to:

• Confirm a diagnosis of hypertension.
• Identify how changes in your blood pressure relate to your daily activities and sleep patterns. Usually, your systolic BP (your top number) decreases about 10% to 20% when you sleep. However, this isn't always the case. Your systolic BP may stay the same or go up.
• See how well your blood pressure medication is controlling your high BP. Your medication may not control your BP throughout the entire day and night. Your provider may need to adjust your dosage or the times that you take your pills, depending on your BP patterns. Or, you may need more than one drug to stabilize your BP.
• Identify changes in your blood pressure readings at your healthcare provider's office versus at home. These changes can help show your level of risk for cardiovascular disease.

Ambulatory blood pressure monitoring can detect abnormal changes in BP that might otherwise go unnoticed. It's a useful way to detect different blood pressure patterns, as listed below.

White coat hypertension

Some people who have normal blood pressure at home have elevated blood pressure in a healthcare setting. This is known as white coat hypertension, or white coat syndrome. It can lead to a hypertension diagnosis when your blood pressure is actually normal. White coat hypertension occurs in 10% to 30% of people with elevated BP readings in healthcare settings.

Current guidelines don't recommend treatment when ambulatory monitoring shows normal readings outside your provider's office. However, research continues to explore this topic. White coat hypertension may still indicate a blood pressure problem. So, you and your provider should keep an eye on it.

Sustained hypertension

This refers to BP readings that are elevated whether you're in your provider's office or at home. Researchers have linked this condition to an increased risk of heart and kidney damage, as well as stroke.

Masked hypertension

This occurs when your BP reading is normal at your provider's office, but elevated when you're at home. It may affect up to 30% of adults who have normal BP readings at their provider's office. You may face a higher risk of developing masked hypertension if you have kidney disease, diabetes or obstructive sleep apnea.

Nocturnal hypertension

This means your BP goes up when you sleep. Nocturnal hypertension affects at least 2 in 10 white people, and about 4 in 10 Black people. It's more common among people who have diabetes or kidney disease. Research continues to explore how nocturnal high BP relates to cardiovascular disease.

Ambulatory blood pressure monitoring can help a wide range of people. Your healthcare provider may recommend ambulatory blood pressure monitoring if you:

• Have high blood pressure based on readings at your provider's office, but you haven't yet started treatment.
• Need changes to your blood pressure medications.
• Still have high blood pressure despite medications.
• Are taking other medications that may affect your blood pressure.
• Have fainting episodes or hypotension (low blood pressure).
• Have high blood pressure during pregnancy.

Yes. Ambulatory blood pressure monitoring is an accurate and effective way to measure your blood pressure. It gives your healthcare provider better data compared with only measuring your BP at your medical appointments.

How do I prepare for ambulatory blood pressure monitoring?

Your healthcare provider will tell you how to prepare. Some general tips include:

• Ambulatory blood pressure monitoring happens outside of your healthcare provider's office. But to get things started, you meet with your provider for an appointment. This is when you receive your equipment and instructions for the 24-hour period.
• You may have disrupted sleep. You may wake up periodically when the device begins measuring your BP. This is normal. But try your best to ignore the sensation and get back to sleep.
• You follow your normal routine. Do what you normally do, but avoid bathing or swimming. Also, avoid heavy exercise. Keep a journal as your provider instructs.
• You take your medications as your provider directs. Ask your provider whether or not you should continue your medications while ambulatory blood pressure measurement is in progress. Follow their guidance closely.

How do you sleep with an ambulatory blood pressure monitor?

You may have trouble sleeping, and that's understandable. You're not used to having a cuff on your arm when you sleep. But try your best to relax. Do whatever you can to make the rest of your sleep environment comfortable.

Ambulatory blood pressure monitoring is an incredibly useful clinical tool that can help you receive the most appropriate care. Among its many benefits, this form of BP monitoring can:

• Accurately measure your blood pressure. This method measures your BP throughout the day rather than just at one or two time points. This is an accurate way to measure your BP and its patterns since your BP normally changes based on time of day and what you're doing at any given moment.
• Rule out white coat syndrome. If your BP is raised only at your provider's office, you have white coat syndrome. Learning this is the case can prevent you from taking unnecessary medications.
• Detect masked hypertension. If your BP is low at your provider's office but high at other times, your typical BP is "masked" (hidden). This cardiovascular disease risk factor would otherwise go unnoticed. In this case, your provider may prescribe medications to lower your BP and lower your risk of stroke and other complications.
• Guide your treatment plan. This monitoring can help evaluate your response to long-acting hypertensive medications. Your provider can adjust your treatment plan as needed.

These are the normal readings for ambulatory blood pressure monitoring:

• 24-hour average: At or below 125/75 mmHg.
• Daytime BP: At or below 130/80 mmHg.
• Nighttime BP: 110/65 mmHg.
• Nocturnal dipping patterns: 10% to 20% drop in BP.

Your provider will tell you when you can expect to see your results. They'll also discuss the results with you and discuss any next steps, like medication changes.