Using a combination of smartwatches researches were able to detect signs early signs for lyme disease and insulin resistance. The biosensors being used were heart rate, skin temperature and blood oxygen level. Computational algorithms were developed using off the shelf smartwatches to detect abnormal physiology signs.

Via PLOS Biology:

Overall, these results indicate that the information provided by wearable sensors is physiologically meaningful and actionable. Wearable sensors are likely to play an important role in managing health.