Abstract Body: Research conducted over recent decades suggests that ambulatory blood pressure monitoring (ABPM), along with its circadian patterns, serves as a more reliable predictor of cardiovascular issues compared to traditional office measurements. Nevertheless, ABPM depends on patient-maintained diaries to document sleep and nap periods, which can introduce inaccuracies and result in data loss, thereby affecting blood pressure calculations and the classification of circadian rhythms. In this study, we aimed to utilize smartwatches to enhance the accuracy of circadian classification in ABPM. 50 patients used ABPM and diaries to identify dipper and non-dipper patterns, while a smartwatch accelerometer analyzed 10-second segments to detect sleep and naps. Movement less than 10% in a 15-minute interval indicated sleep or rest, 10-20% indicated ambiguous periods, and over 20% indicated daily activity. Hospitalized diabetic patients averaged 3.1±2.2 hours of napping, with a range of 0-7.9 hours.
Without the use of the smartwatch as an auxiliary tool, 7, 30, and 13 individuals were initially categorized as dippers, non-dippers, and reverse dippers, respectively. However, upon employing the accelerometer to more precisely identify sleep and nap periods, the classification was adjusted to 9, 27, and 14 individuals as dippers, non-dippers, and reverse dippers, respectively. 15 individuals were reclassified due to the precise exclusion of napping time in daytime calculations. For example, one patient took a nap between 14:45 and 15:45, which was not recorded in his diary log. This omission led to a reduction in the mean daytime blood pressure and decreased the disparity in blood pressure between periods of daily activity and sleep. (Fig.1) The incorporation of smartwatches has enhanced the precision of circadian rhythm subgroup classification for ABPM by 30%. Therefore, it can be concluded that employing smartwatches for the detection of sleep and naps can mitigate errors and enhance the accuracy of ABPM analysis.