Validity of the Elite HRV Smart Phone Application for Examining Heart Rate Variability in a Field Based Setting.
The introduction of smart phone applications has allowed athletes and practitioners to record and store R-R intervals on smart phones for immediate heart rate variability (HRV) analysis. This user-friendly option should be validated in the effort to provide practitioners confidence when monitoring their athletes before implementing such equipment.The objective of this investigation was to examine the relationship between a vagal related HRV index, rMSSD when derived from a smart phone application accessible with most smart phone operating systems against Kubios HRV 2.2R-R intervals were recorded immediately upon awakening over 14 consecutive days using the Elite HRV smartphone application. R-R recordings were then exported into Kubios HRV 2.2 for analysis. The relationship between rMSSDln derived from Elite HRV and Kubios HRV 2.2 was examined using a Pearson Product Moment Correlation and a Bland-Altman Plot.An extremely large relationship was identified (r = 0.92; p < 0.0001; CI 95% = 0.90;0.93). A total of 6.4% of the residuals fell outside of the 1.96 ±SD (CI 95% = -12.0%; 7.0%) limits of agreement. A negative bias was observed (mean: -2.7%; CI 95% = -3.10%;-2.30%) whose CI 95% failed to fall within the line of equality.Our observations suggest Elite HRV as a non-valid smart phone application for examining rMSDDLn when compared to Kubios HRV 2.2. We propose further research is warranted to confirm our observations and to identify if this smart phone application may be reliable rather than valid when assessing parasympathetic modulation.