Standardizing photoplethysmography (PPG) for clinical-grade wearable sensing

Photoplethysmography (PPG) underpins a rapidly expanding ecosystem of wearable devices that promise continuous, non-invasive cardiovascular monitoring. Yet, despite widespread adoption, the field lacks consensus on how PPG signals should be acquired, processed, validated, and reported. This fragmentation limits reproducibility, obscures performance claims, and hinders clinical translation. We argue that standardization across the PPG pipeline, from hardware design to algorithmic interpretation, is essential for transforming wearable optical sensing from a consumer technology into a clinically trusted modality. We outline key sources of variability, identify critical gaps in current practice, and propose a coordinated roadmap to enable reproducible science, regulatory clarity, and equitable deployment.