Create a shortcut on your iPhone? Your watch? Airplay what to the Watch? Didn't know you could Airplay anything to the Watch!
Doesn't having an ongoing connection running a shortcut drain the watch's battery?
In any case, isn't it even easier to simply tap on the heart rate complication to get regular heart rate monitoring?
In any case, it a good avoid faking an exercise because that undermines a key heart health stat, VO2 max.