Blood pressure monitoring over short day and night times cannot predict 24-hour average blood pressure

Marco Di Rienzo, Gianfranco Parati, Guido Pomidossi, Marco Veniani, Antonio Pedotti, Giuseppe Mancia

Research output: Contribution to journalArticlepeer-review


Evidence has been produced that average 24-h or day-time blood pressure (BP) values provide a better diagnosis of hypertension and a better prediction of its risk than BP values provided by one or few isolated measurements. This has led to a number of attempts to simplify the time-consuming procedure necessary to obtain this information and to identify short periods during the 24 h when average BP might closely reflect the 24-h or day-time average values. In 40 ambulant subjects BP was recorded intra-arterially for 24 h using the Oxford method. The BP signal was analysed beat-to-beat by a computer to obtain the average 24-h mean BP values. This value was compared with the mean BP average values obtained by beat-to-beat analysis of subperiods of the same recording, ranging from 30 min to 12 h in duration. For each duration the analysis was performed on 48 different subperiods, each shifted by 30 min from the preceding one, so that every time interval within the 24 h was considered. Throughout the 24-h period the average mean BP values obtained by the analysis of the 30-min subperiods showed very marked differences compared to the 24-h mean BP average. The differences between the subperiod and 24-h values showed a progressive reduction as the subperiod duration was increased. Their magnitude, however, was still marked for subperiods of 2 and 4 h, and only showed a clear-cut attenuation when the subperiods encompassed 12 h. The magnitude and the sign of all the subperiod and 24-h differences showed a large variability among subjects. Similar results were observed when the comparisons were between day-time subperiods and the corresponding day-time average value. These findings demonstrate that average BP values obtained by monitoring BP over a period of a few hours during the day or night cannot provide a precise estimate of the 24-h or the day-time average BP. This rules out the possibility of shortening the procedure necessary to obtain this important information.

Original languageEnglish
Pages (from-to)343-349
Number of pages7
JournalJournal of Hypertension
Issue number4
Publication statusPublished - 1985


  • 24-Hour blood pressure
  • Correlation indices
  • Hypertension
  • Intra-arterial blood pressure monitoring
  • Non-invasive blood pressure monitoring

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Internal Medicine
  • Endocrinology


Dive into the research topics of 'Blood pressure monitoring over short day and night times cannot predict 24-hour average blood pressure'. Together they form a unique fingerprint.

Cite this