Before revision:  This overview paper covers considerations and settings for building a HAR healthcare system, including sensor factors , AI model comparison, and system challenges .
After revision:  This overview paper covers considerations and settings for building a HAR healthcare system, including sensor factors (e.g., type, number, and placement location), AI model selection (e.g., classical machine learning models versus deep learning models), and feature engineering. In addition, we highlight the challenges of such healthcare-oriented HAR systems and propose several research opportunities for both the medical and the computer science community .