ASSESSMENT OF NOCTURNAL BLOOD PRESSURE: THE CRITICAL ROLE OF TIME IN BED

Objective: Nocturnal blood pressure (BP) monitoring is essential for evaluating cardiovascular risk and guiding treatment decisions. However, the standardized night-time period between 10 p.m. and 6 a.m. may not accurately reflect the individual sleep schedule. This pilot study aimed to investigate the comparability between the standardized night-time period and actual time in bed (TIB) regarding BP assessment. Further, our goal was to evaluate the clinical relevance of the observed BP differences. Design and method: A total of 30 participants underwent 24-hour ambulatory blood pressure monitoring (ABPM). The patient specific TIB was precisely assessed through an accelerometer and a position sensor from the SOMNOtouch NIBP™ (SOMNOmedics GmbH, Randersacker, Germany). Results: We observed differences in both systolic and diastolic BP between the standardized night-time period and the TIB. Furthermore, a notable percentage of patients (27%) changed their dipping pattern classification as a function of the night-time definition adopted. We found strong correlations between the start (r = 0.75, p < 0.01), as well as the duration (r = -0.42, p = 0.02) of TIB and the changes in dipping pattern classification. Conclusions: Definition of nocturnal period based on the TIB leads to clinically relevant changes of nocturnal BP and dipping pattern classifications. TIB is easily detected using a body position sensor and accelerometer. This approach may thus improve the accuracy of cardiovascular risk evaluation and enhance treatment strategies.