Wearable Device Health Anomaly Detection System

Create an advanced anomaly detection system for continuous health monitoring using data from wearable devices. Develop a Python script that can process high-frequency time-series data from fitness trackers and medical-grade wearables, implementing multiple machine learning algorithms to identify potential health risks. The solution should include real-time alerting mechanisms, handle multiple data streams simultaneously, and provide a robust error handling system for incomplete or inconsistent data inputs.