Simple Biometrics Aggregator from SmartWatch or FitnessTracker

I am looking to build a simple biometrics aggregator using existing SmartWatch/FitnessTracker technology. Ideally a cheaper device with accurate sensors/data and API support but I am open to the device type. The data must be output onto the device as a smartwatch/fitnesstracker app, a DB or web app in real time (the output location isn't that import, but must be real time). Reach out for more details.

This is the first step in a long term project. Ideally looking to find someone not just for this task but a longer term partnership to develop the product if things go well.