I think that wearables are a distinct market. The fashion, the status-quo that some trademarks give, are a factor to consider.
Watches perhaps are a perfect example:
Watches are no longer a tool, are more a kind of a jewel. So I think it makes more sense to have big trademarks on that space to make smart watches as jewelry: Rolex, etc...
Heart rate monitoring and sports-bands offer another market which has nothing to do with the jewelry watches, but I don't think its usefullness make for a whole new device like a watch: a bluetooth enabled band that will act as phone's plugin is enough probably.