I take GTX classes and group members wear chest straps to monitor heart rates which are displayed on a large screen. I have an Apple Watch that I use to track activity and monitor heart rate but it does not pair with this system, even though the instructors use an iPad and Bluetooth to connect and display heart rates. The chest straps are not something I would use any other time and are not even sold at the store in my club which makes me feel like they are being phased out. With the popularity and capabilities of the Apple Watch, it really doesn’t make sense that they are not compatible with the iPad and screens for these classes.