Ambulatory blood pressure monitoring (ABPM) is a method of taking regular blood pressure readings over a 24- or 48-hour period. This is accomplished with a special device that is worn at all times and measures blood pressure automatically, recording the readings.

Studies have shown that ABPM is a valuable tool in the diagnosis of several conditions.  It is also beneficial for adjusting doses of medication for high blood pressure and even predicting cardiac events in certain patients.

Blood pressure is a measure of the force, or tension, of the blood against the walls of the arteries. High blood pressure puts an added workload and strain on the heart, whereas low blood pressure (hypotension) can lead to fainting (syncope). High blood pressure (hypertension) is a very common disease in America. It is considered a major risk factor for heart attacks and strokes. 

Blood pressure is measured with the use of an arm cuff (sphygmomanometer) and expressed as systolic pressure over diastolic pressure. Systolic pressure is the highest level of the blood’s pressure within the artery walls and corresponds to the contraction of the ventricle. Diastolic pressure is the lowest pressure at which blood stays within the aorta. Both are measured in millimeters of mercury (mmHg).

In most cases, blood pressure is measured in a physician’s office. In recent years, blood pressure measuring equipment has become available that allows people to measure their blood pressure easily and affordably at home. In addition, monitoring equipment is often found in public places, such as grocery stores and pharmacies. However, all of these approaches have certain disadvantages that make ABPM an attractive option for some individuals. For example, in the case of blood pressure measurements at a physician’s office, many people suffer from  “white coat hypertension,” or high blood pressure as a result of anxiety connected to the blood pressure test itself. Similarly, the at-home tests and those completed out of a medical setting may be inconsistent and unreliable.

By contrast, the ABPM measures blood pressure at regular intervals throughout the monitoring period, including at night when the patient is asleep. It then records these measurements. Coupled with an activity diary, the ABPM can give a physician a very accurate picture of factors that may be affecting a patient’s blood pressure, such as exercise, eating, medications and certain forms of heart disease.

This information is useful for a variety of reasons. For example, it may help the physician adjust the dosages of antihypertensive medication. Many studies have shown that blood pressure spikes in the morning, right around the time that 24-hour antihypertensives are at their weakest. Thus, heart attacks and strokes may be more likely to occur in the morning. An ABPM could help identify this situation, and the physician could adjust the patient’s medication accordingly. Studies have also shown that ABPM may be a better predictor for certain cardiac events than other methods of measuring blood pressure.