Very short-term beat-by-beat blood pressure variability in the supine position at rest correlates well with the nocturnal blood pressure variability assessed by ambulatory blood pressure monitoring.

Blood pressure variability (BPV) is an important indicator in risk stratification for hypertension. Among the daily BPVs assessed using a 24-h ambulatory blood pressure (BP) monitor nocturnal systolic BPV has been suggested to predict cardiovascular risks. We hypothesized that very short-term BPV at rest would correlate with nocturnal BPV because of the shared autonomic BP regulatory system under no daily exertion. Thirty untreated normotensive and hypertensive adults underwent 30-min continuous beat-by-beat BP recordings in the supine position, followed by 24-h ambulatory blood pressure monitoring (ABPM). The relationship between very short-term BPV (standard deviation (SD), coefficient of variation (CV)) and daytime and nocturnal BPV (SD, CV, average real variability (ARV), and standardized ARV (CV-ARV)) was assessed with Pearson's correlation coefficients. Very short-term BPV correlated significantly with nocturnal BPV (ARV, r = 0.604, p < 0.001) but not with daytime BPV. These trends were more pronounced with the increasing data length of continuous beat-by-beat BP recording. Using a data segment from the last 10 min of a 30-min continuous beat-by-beat BP recording resulted in a stronger correlation between very short-term BPV and nocturnal BPV than using earlier segments. The findings of this study suggest that very short-term BPV in the supine position at rest may predict nocturnal BPV. Since the burden of ABPM for patients has hindered clinical dissemination, very short-term BPV has the potential to develop a novel index of BPV.