This lecture explores the challenges of communication energy in centralized medical informatics and introduces distributed machine learning as an energy-efficient alternative, where data is summarized and sent to a central data center for model computation. The instructor discusses the importance of energy efficiency in IoT devices and explains how summarizing data on nodes can improve overall efficiency. Additionally, the lecture covers opportunities and challenges in the IoT era, focusing on big data, personal health, wearable and mobile health technologies, and solutions like resource-aware and distributed machine learning techniques.