Common technologies used in wearable devices include sensors, microcontrollers, and wireless communication protocols. Sensors measure various physiological parameters, such as heart rate, temperature, and activity levels, enabling real-time health monitoring. Microcontrollers process this data and execute commands, while wireless protocols like Bluetooth and Wi-Fi facilitate communication with smartphones or other devices. Furthermore, wearables may incorporate GPS for location tracking and can leverage cloud computing for data storage and analysis. Together, these technologies enhance the functionality and usability of wearable devices in health, fitness, and lifestyle applications.