Ambulatory blood pressure monitoring
Blood pressure measured over 24 hours, outside the office. It separates real hypertension from a nervous reading.
What it measures
- What it measures
- Takes blood pressure automatically across a full day and night. It gives the true average, the difference between waking and sleeping, and detects pressure that rises only at the office - or only away from it.
- Duration
- 24 hours
- Preparation
- No fasting. Bring any previous test results and the list of medicines you take.
- What it feels like
- A cuff inflates on your arm at set intervals, including at night. It does not hurt, but it interrupts sleep.
- Referral from another doctor
- No
- Results
- Same day
- Where it is done
- Fitted at the office, then worn at home
What it shows
The axis spans a day and carries NO hour marks, on purpose: the readings are a rhythm, not a frequency, and counting them on a calibrated axis would state how often a particular device measures. The diagram declares no pressure figures either, and draws no trend: that is for the doctor to read in the report.
- 01
- The readings. The cuff inflates on its own every so often and stores the measurement. None of them needs you to do anything.
- 02
- While you sleep. The readings space out there, to disturb you as little as possible. Where that stretch falls depends on your hours, not on the device.
- 03
- The whole day. The device goes with you and records without stopping: while you work, while you walk and while you sleep.
A single office reading says very little. Some patients only run high once they arrive at the clinic, and others - the riskier case - look fine at the office and are high the rest of the day.
Ambulatory monitoring settles both, because it measures where the patient actually lives. The most useful number is usually the night-time drop: a heart that does not lower its pressure during sleep is working twenty-four hours a day, and that changes treatment.
It is also the test that decides whether stubborn hypertension is truly resistant or whether the medication schedule is simply badly distributed across the day.