Agreement Between A Smartphone Pulse Sensor And Electrocardiography For Determining Hrv In Three Different Positions

Abstract

PURPOSE: To determine the agreement between a smartphone pulse sensor (PS) and electrocardiography (ECG) for determining ultra-short-term heart rate variability (HRV) in three different positions. METHODS: Thirty college-aged men (n = 15) and women (n = 15) volunteered to participate in this study. Sixty second heart rate measures were simultaneously taken with the PS and ECG in supine, seated and standing positions. The log transformed root mean square of successive R-R interval differences (lnRMSSD) was calculated from the PS and ECG. RESULTS: The lnRMSSD values were 81.5 ± 11.7 via PS and 81.6 ± 11.3 via ECG (p = 0.63, Cohen’s d = 0.01) in the supine position, 76.5 ± 8.2 via PS and 77.5 ± 8.2 via ECG (p = 0.007, Cohen’s d = 0.11) in the seated position, and 66.5 ± 9.2 via PS and 67.8 ± 9.1 via ECG (p < 0.001, Cohen’s d = 0.15) in the standing positions. The PS values showed a near perfect correlation to the ECG in all three positions (r values ranged from 0.98 to 0.99). In addition, the limits of agreement (CE ± 1.98 SD) were -0.13 ± 2.83 for the supine values, -0.94± 3.47 for the seated values, and -1.37 ± 3.56 for the standing values. CONCLUSIONS: The results of the study suggest good agreement between the PS and ECG for measuring lnRMSSD in supine, seated, and standing positions. Though significant differences were noted between the two methods in the seated and standing positions, the effect sizes were trivial (i.e., Cohen’s < 0.20). In addition, PS provided tight limits of agreement to the criterion method in all three positions. Therefore, the PS method appears to provide a suitable alternative to ECG for measuring ultra-short-term lnRMSSD.