Using ANT+ accessories in the iWorld I'd like to track my fitness more automatically than I do now, because now it's not automatic, so I don't do it.

In particular I'm interested in getting an ANT+ odometer for my bike. I understand that the iPhone can read these, but it is not clear whether that means it reads it into the Health app, or I still have to use some 3rd party solution. Does anyone know of a meter that goes directly into Health?

And then there's the Apple Watch. Can the Watch talk to any of these devices directly? That would certainly be wonderful because then I wouldn't have to carry my phone on bike rides.
No iOS device has native ANT+ communication support built in. For the iPhone 4 &amp; 4s, Wahoo makes a 30 pin ANT+ dongle. Newer devices can also utilize this dongle with a 30 pin to Lightning adapter.

http://www.wahoofitness.com/devices/wahoo-key-16.html

Once your setup with the ANT+ dongle, you'll need a 3rd party app to read the data. Some, like Strava, can push data to the iOS Health app:

https://support.strava.com/hc/en-us/articles/216917527-Health-App-Integration-iPhone