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Ambulatory blood pressure monitoring

Medical Professionals

Professional Reference articles are designed for health professionals to use. They are written by UK doctors and based on research evidence, UK and European Guidelines. You may find the High blood pressure article more useful, or one of our other health articles.

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What is ambulatory blood pressure monitoring?

Ambulatory blood pressure monitoring (ABPM) is a non-invasive method of obtaining blood pressure readings over a 24-hour period, whilst the patient is in their own environment, representing a true reflection of their blood pressure.

Many studies have now confirmed that blood pressure measured over a 24-hour period is superior to clinic blood pressure in predicting future cardiovascular events and target organ damage.1

See also the related separate Hypertension article.

What does ambulatory blood pressure monitoring involve?

Blood pressure is measured over a 24-hour period, using auscultatory or oscillometry devices, and requires use of a cuff. The monitor takes blood pressures every 20 minutes (less frequently overnight - eg, one-hourly).2

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What are the uses of ambulatory blood pressure monitoring?3

  • To obtain a twenty-four hour record - more reliable than one-off measurements. Studies have shown that increased blood pressure readings on ABPM are more strongly correlated to end-organ damage than one-off measurements - eg, left ventricular hypertrophy.4

  • To detect white coat hypertension.

  • It has use in hypertension research - eg, reviewing 24-hour profile of antihypertensive medication.

  • It may have prognostic use - higher readings on ABPM are associated with increased mortality.5

  • Response to treatment.4

  • Masked hypertension.

  • Episodic dysfunction.

  • Autonomic dysfunction.

  • Hypotensive symptoms whilst on antihypertensive medications.

  • It may be more cost-effective in the long term than office blood pressure measurement.

Who should be referred for ambulatory blood pressure monitoring?6

  • The National Institute for Health and Care Excellence (NICE) recommends that if a clinic blood pressure is 140/90 mm Hg or higher, ABPM should be offered to confirm the diagnosis of hypertension. If a person is unable to tolerate ABPM, home blood pressure monitoring (HBPM) is a suitable alternative to confirm the diagnosis of hypertension.7

  • Poorly controlled hypertension - eg, suspected drug resistance.

  • Patients who have developed target organ damage despite control of blood pressure.

  • Patients who develop hypertension during pregnancy.

  • High-risk patients - eg, those with diabetes mellitus, those with cerebrovascular disease, and kidney transplant recipients.

  • Suspicion of white coat hypertension - high blood pressure readings in clinic which are normal at home.

  • Suspicion of reversed white coat hypertension, ie blood pressure readings are normal in clinic but raised in the patient's own environment.

  • Postural hypotension.

  • Elderly patients with systolic hypertension.

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Upper limit of normal ambulatory blood pressure monitoring values

Normal ambulatory blood pressure during the day is <135/<85 mm Hg.7

Disadvantages of ambulatory blood pressure monitoring3

  • It is not universally available although this is improving.

  • It requires specialist training and is not common in the USA.8

  • Some patients find inflation of the cuff unbearable.

  • Sleep disturbance.

  • Bruising might be seen where the cuff is located.

  • Background noise may lead to interference (less with oscillometric methods).

  • Poor technique and arrhythmias may cause poor readings.

  • HBPM may be better than ABPM for monitoring response to treatment.2

How are the results of ambulatory blood pressure monitoring provided?

  • This varies according to the machines used.

  • Usually, they have individual systolic and diastolic pressures. These may also be represented in a graphic form.

  • Blood pressure load - the percentage or proportion of readings that are higher than a predetermined level in twenty-four hours.

  • NICE recommends ensuring that at least two measurements per hour are taken during the person's usual waking hours (for example, between 08:00 and 22:00 hours). Use the average value of at least 14 measurements taken during the person's usual waking hours to confirm a diagnosis of hypertension.7

Dippers and non-dippers

  • Blood pressure will fall at night in normotensive individuals. People who undergo this normal physiological change are described as 'dippers'.9

  • In 'non-dippers' the blood pressure remains high, ie less than 10% lower than daytime average. There is also the phenomenon of 'reverse dippers' whose blood pressure actually rises at night. Both these conditions have also been reported to be associated with a poor outcome.10

Further reading and references

  • Hermida RC, Ayala DE, Mojon A, et al; Decreasing sleep-time blood pressure determined by ambulatory monitoring reduces cardiovascular risk. J Am Coll Cardiol. 2011 Sep 6;58(11):1165-73. doi: 10.1016/j.jacc.2011.04.043.
  • Williams B, Mancia G, Spiering W, et al; 2018 ESC/ESH Guidelines for the management of arterial hypertension: The Task Force for the management of arterial hypertension of the European Society of Cardiology and the European Society of Hypertension: The Task Force for the management of arterial hypertension of the European Society of Cardiology and the European Society of Hypertension. J Hypertens. 2018 Oct;36(10):1953-2041. doi: 10.1097/HJH.0000000000001940.
  • Whelton PK, Carey RM, Aronow WS, et al; 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Hypertension. 2018 Jun;71(6):1269-1324. doi: 10.1161/HYP.0000000000000066. Epub 2017 Nov 13.
  1. Guirguis-Blake JM, Evans CV, Webber EM, et al; Screening for Hypertension in Adults: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force. JAMA. 2021 Apr 27;325(16):1657-1669. doi: 10.1001/jama.2020.21669.
  2. Tse T, Wu B, Vagholkar S, et al; Revisiting ambulatory blood pressure monitoring. Aust J Gen Pract. 2022 Aug;51(8):636-638. doi: 10.31128/AJGP-10-21-6217.
  3. Huang QF, Yang WY, Asayama K, et al; Ambulatory Blood Pressure Monitoring to Diagnose and Manage Hypertension. Hypertension. 2021 Feb;77(2):254-264. doi: 10.1161/HYPERTENSIONAHA.120.14591. Epub 2021 Jan 4.
  4. Posokhov IN, Kulikova NN, Starchenkova IV, et al; The "Pulse Time Index of Norm" highly correlates with the left ventricular mass index in patients with arterial hypertension. Vasc Health Risk Manag. 2014 Mar 19;10:139-44. doi: 10.2147/VHRM.S58351. eCollection 2014.
  5. O'Brien E, Parati G, Stergiou G, et al; European Society of Hypertension position paper on ambulatory blood pressure monitoring. J Hypertens. 2013 Sep;31(9):1731-68. doi: 10.1097/HJH.0b013e328363e964.
  6. CKS Hypertension; NICE CKS, March 2023 (UK access only)
  7. Hypertension in adults: diagnosis and management; NICE (August 2019 - last updated November 2023)
  8. Cepeda M, Pham P, Shimbo D; Status of ambulatory blood pressure monitoring and home blood pressure monitoring for the diagnosis and management of hypertension in the US: an up-to-date review. Hypertens Res. 2023 Mar;46(3):620-629. doi: 10.1038/s41440-022-01137-2. Epub 2023 Jan 5.
  9. Mahabala C, Kamath P, Bhaskaran U, et al; Antihypertensive therapy: nocturnal dippers and nondippers. Do we treat them differently? Vasc Health Risk Manag. 2013;9:125-33. doi: 10.2147/VHRM.S33515. Epub 2013 Mar 24.
  10. Altikardes ZA, Kayikli A, Korkmaz H, et al; A novel method for dipper/non-dipper pattern classification in hypertensive and non-diabetic patients. Technol Health Care. 2019;27(S1):47-57. doi: 10.3233/THC-199006.

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The information on this page is written and peer reviewed by qualified clinicians.

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