There are no set numbers that indicate a normal result with ambulatory blood pressure monitoring (ABPM). Analysis of an ambulatory blood pressure profile is complex and relies on the interpretation of not only the raw numbers provided by the monitor, but also the circumstances surrounding the patient at the time of the test (as recorded in the patient log).

In general, a person’s blood pressure peaks during the daytime hours and falls to its lowest point overnight. In the early morning, blood pressure usually rises from the patient’s overnight low to the daytime level very quickly. This is one reason that this time period is considered riskier for cardiovascular events, such as a heart attack or stroke.

In addition to this daily cycle, healthy individuals tend to have:

Any deviation from this general pattern can assist physicians in interpreting the ABPM results and making a diagnosis. For instance, a patient whose blood pressure readings do not dip at night might have a disorder of the autonomic nervous system, the body system that controls “automatic” functions such as heartbeat and breathing.