Wearable fitness trackers collect and analyze data through a combination of embedded sensors, algorithms, and mobile applications. These devices monitor various physiological metrics, such as heart rate, steps taken, and sleep patterns, using sensors like accelerometers and optical heart rate monitors. The data is transmitted to connected mobile apps, where it is processed, and users receive insights about their fitness and health. These trackers promote awareness and motivate healthy behaviors, allowing users to set goals, track progress, and receive personalized feedback based on the data collected.