WHOOP wrist-based photoplethysmography demonstrated acceptable agreement with ECG for heart rate (bias ≤0.39%), but HRV bias (1.66%) approached or exceeded the smallest worthwhile change.
Observational
Does WHOOP wrist-based photoplethysmography accurately measure heart rate and heart rate variability compared to electrocardiogram?
WHOOP provides acceptable accuracy for heart rate measurement compared to ECG, but its heart rate variability measurements should be interpreted with caution due to bias approaching the smallest worthwhile change.
Heart rate (HR) and HR variability (HRV) infer readiness to perform exercise in athletic populations. Technological advancements have facilitated HR and HRV quantification via photoplethysmography (PPG). This study evaluated the validity of WHOOP's PPG-derived HR and HRV against electrocardiogram-derived (ECG) measures. HR and HRV were assessed via WHOOP and ECG over 15 opportunities. WHOOP-derived pulse-to-pulse (PP) intervals were edited with WHOOP's proprietary filter, in addition to various filter strengths via Kubios HRV software. HR and HRV (Ln RMSSD) were quantified for each filter strength. Agreement was assessed via bias and limits of agreement (LOA), and contextualised using smallest worthwhile change (SWC) and coefficient of variation (CV). Regardless of filter strength, bias (≤0.39 ± 0.38%) and LOA (≤1.56%) in HR were lower than the CV (10-11%) and SWC (5-5.5%) for this parameter. For Ln RMSSD, bias (1.66 ± 1.80%) and LOA (±5.93%) were lowest for a 200 ms filter and WHOOP's proprietary filter, which approached or exceeded the CV (3-13%) and SWC (1.5-6.5%) for this parameter. Acceptable agreement was found between WHOOP- and ECG-derived HR. Bias and LOA in Ln RMSSD approached or exceeded the SWC/CV for this variable and should be interpreted against its own level of bias precision.
Bellenger et al. (Thu,) conducted a observational in Athletic populations. WHOOP wrist-based photoplethysmography (PPG) vs. Electrocardiogram (ECG) was evaluated on Agreement of HR and HRV (Ln RMSSD) assessed via bias and limits of agreement. WHOOP wrist-based photoplethysmography demonstrated acceptable agreement with ECG for heart rate (bias ≤0.39%), but HRV bias (1.66%) approached or exceeded the smallest worthwhile change.