A 24-hour blood pressure monitor (also called an ambulatory blood pressure monitor, or ABPM) is a small device worn on your belt or in a pouch that automatically measures your blood pressure at regular intervals throughout the day and night. It gives a far more complete picture of blood pressure than a single reading in a clinic.
Why is it Done?
A 24-hour monitor is used to:
- confirm a diagnosis of high blood pressure (hypertension)
- detect white coat hypertension — blood pressure that is elevated in the clinic but normal at home
- detect masked hypertension — blood pressure that appears normal in the clinic but is elevated during daily activities
- assess whether blood pressure falls normally during sleep, and whether medication is effective throughout the day
What to Expect
A cuff is placed on your upper arm and connected by a short tube to a small recorder. During the day the cuff inflates automatically every 20–30 minutes; at night every 30–60 minutes. You will feel the cuff tighten briefly with each reading. A diary card is provided to note your activities, meals, and sleep times.
Try to keep your arm still and relaxed each time the cuff inflates — this gives the most accurate reading.
Daily Life
You can go about your normal activities, including work and light exercise. Avoid submerging the device in water — you cannot shower or bathe while wearing it. The monitor is returned to the clinic the following morning.
Is it Safe?
Yes. The device only records — it does not deliver any current. The cuff inflations may briefly disturb sleep, but this settles for most people within the first night.