The function of smartwatch today can outperform what is available in 4 to 5 years ago. With the new Apple Watch able to record single channel ECG, new Apple Watch patent to USPTO shows possibility to record blood glucose level.
The patent shows that the device emits electromagnetic wave that can detect the reflective energy of the object, thus obtaining data from the blood and induce blood glucose level. It can even be use to detect skin cancer or other related disease.
However, such technology makes the Apple Watch vulnerable to water as the sensor is exposed outside. However, innovation may be in place to fit everything inside the watch while maintaining water resistant integrity.