Reliability of Beat-to-Beat Blood Pressure Variability in Humans

David Valdez Rendon; Carson Newton; Lydia valtadoros; Jeremy bigalke; Jason Carter

doi:10.1152/physiol.2026.41.S1.2298052

Abstract only Introduction: Heart rate variability (HRV) is an established predictor of cardiovascular risk. Likewise, beat-to-beat blood pressure variability (BPV) has gained recent attention as a prognostic cardiovascular health indicator. The efficacy of BPV as a risk stratification tool is conditional upon its reliability across time. However, few studies have investigated beat-to-beat BPV reliability across time in healthy adults. The purpose of the current study was to evaluate the reliability of BPV across 2-, 5-, and 10-min recording durations alongside commonly used HRV metrics. We hypothesized that reliability of both variability measures would increase with recording duration. Methods: 10-minutes of resting heart rate (HR, electrocardiogram) and beat-to-beat blood pressure (BP, finger plethysmography) were recorded in 79 participants (40 females; age: 23±5 yr; BMI: 25±4 kg/m 2 ) on two separate occasions separated by ~1 month. Systolic and diastolic BP variabilities were obtained using the standard deviation (SBPv and DBPv) and coefficient of variation (SBPcv and DBPcv) calculations. HRV was assessed using time (RMSSD) and frequency-domain (HF, LF, & LF/HF) metrics. All BPV and HRV measures were quantified across 2, 5, and 10-minute durations. Intraclass correlation coefficient (ICC) was used to assess the relative reliability across each recording duration. Further interpretation of reliability was assessed using ICC ranges (< 0.5= “poor”; 0.5-0.75= “moderate”, 0.75-0.9= “good”; >0.9= “excellent”). Results: Overall, the complete set of variability metrics experienced greater reliability with increases in recording duration (all p £0.001). Systolic and diastolic blood pressure variability showed good-moderate reliability at a 10-min duration (SBPv: ICC= 0.664; SBPcv: ICC= 0.633; DBPv: ICC= 0.674; DBPcv: ICC= 0.597, all p £0.001). In contrast, frequency domain HRV measures exhibited good-to-excellent reliability (HF: ICC= 0.903; LF: ICC = 0.765, all p< 0.001), with the exception of LF/HF, which demonstrated good-moderate reliability (ICC= 0.629, p< 0.001). Time-domain HRV measures displayed excellent reliability (RMSSD: ICC= 0.904, p< 0.001). Conclusion: Beat-to-beat BPV tended to have poor-to-moderate relative reliability with shorter recording duration, though relative reliability increased to good-moderate with 10-min recording duration. Similar recording-duration-dependent increases in reliability were observed across HRV metrics. Time-domain HRV tended to have the best relative reliability compared to both frequency HRV and BPV metrics. In comparison with time-domain HRV, frequency-domain HRV metrics were less reliable, with HF as an exception. When compared to RMSSD, the complete set of BPV metrics tended to be less reliable than time-domain HRV. The present findings demonstrate reliability of time-domain HRV, supporting its use as a risk stratification tool for an extended recording duration. In contrast, these findings highlight reduced reliability of BPV metrics relative to time-domain HRV, hindering their effectiveness as a risk stratification tool. Lastly, our findings demonstrate the importance of recording duration when assessing reliability of autonomic and cardiovascular variables. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Reliability of Beat-to-Beat Blood Pressure Variability in Humans

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