AnyPPG: An ECG-Guided PPG Foundation Model Trained on Over 100,000 Hours of Recordings for Holistic Health Profiling

Abstract: Background: Photoplethysmography (PPG) offers a noninvasive and accessible modality for health monitoring beyond clinical settings. However, existing studies are limited by the scale and diversity of labeled data, constraining model accuracy, generalizability, and the exploration of broader applications. This study investigates the potential of PPG for holistic health profiling through the integration of foundation model techniques. Methods: We present AnyPPG, a PPG foundation model pretrained on large-scale, multi-source synchronized PPG-ECG data. By aligning PPG and ECG representations within a shared space, AnyPPG learns physiologically meaningful features from unlabeled signals. Its capability was further evaluated across a diverse set of downstream tasks, encompassing both conventional physiological analysis and comprehensive multi-organ disease diagnosis. Results: Across eleven physiological analysis tasks spanning six independent datasets, AnyPPG achieved state-of-the-art performance, with average improvements of 12.8% in regression and 9.1% in classification tasks over the next-best model. In multi-organ disease diagnosis, AnyPPG demonstrated broad cross-system diagnostic potential. Among 1,014 ICD-10 three-digit disease categories, 13 achieved an AUC above 0.8 and 137 exceeded 0.7. Beyond strong performance in cardiovascular diseases such as heart failure, valvular disorders, and hypertension, AnyPPG also showed substantial diagnostic value for non-cardiovascular conditions, exemplified by Parkinson's disease (AUC = 0.78) and chronic kidney disease (AUC = 0.74). Conclusions: AnyPPG demonstrates that a PPG foundation model trained through physiological alignment with ECG can produce accurate and robust signal representations. Building on this capability, it underscores the potential of PPG as a modality for comprehensive assessment of systemic and multi-organ health.