Pulse Rate Variability Is Not the Same as Heart Rate Variability: Implications for Sports Performance and Injury...

Area of Science:

• Sports Science
• Physiology
• Biomedical Engineering

Background:

• Heart rate variability (HRV) via ECG monitors autonomic function.
• Wearable devices often use photoplethysmography (PPG) for pulse rate variability (PRV).
• The agreement between PRV and HRV in athletes is not well-established.

Purpose of the Study:

• To investigate the agreement between PRV and HRV in beat-to-beat analysis.
• To assess if PRV can detect autonomic deviations similarly to HRV.

Main Methods:

• Analyzed data from 103 Division I collegiate American football athletes over three seasons.
• Measured heart rate (HR), pulse rate (PR), rMSSD, and SDNN.
• Utilized Bland-Altman analysis and sliding-window z-score threshold-crossing analysis.

Main Results:

• PPG-PRV values (rMSSD, SDNN) were lower than ECG-HRV.
• Bland-Altman analysis revealed negative bias for PRV indices.
• PRV detected fewer autonomic events and showed a 1.8-5.5 day delay compared to HRV.

Conclusions:

• PPG-PRV is not an equivalent surrogate for ECG-HRV in tracking autonomic function.
• The delay in PRV response hinders timely intervention for autonomic deterioration.
• Using 'HRV' for PPG-derived data can cause confusion among researchers and consumers.