I've had my 5X for almost 2 months now. Love it. I've gone on runs, taken spin classes, and I even teach barbell workout classes several times a week... and the heart rate has been surprisingly very accurate compared the chest strap I had with my 920XT. BPM's measure from the 70's all the way to 150's during these activities. Yesterday, I decided to use my watch to broadcast my heart rate to the receiver in the gym where it could be seen on the television screen along with all my participants who also had their own monitors. (Think orange theory type classes) The broadcast worked the entire class, BUT the watch failed big time in accurately reading my HR. For example, it frequently reported my BPM in the 30's. (For the 30 minute workout, my average BPM was reported as 54, with a max of 79) For reference, my resting HR is in the low 40's. As soon as I stopped broadcasting, the watch went back to normal. For example, as I'm showering after class, it showed around 80BPM. Side note, I sweat a ton when I'm spinning or outside for a run. During these classes, my arms/wrists barely get damp with sweat. Has anyone experienced this? It was almost as if the BPM reading was cut in half or something while broadcasting. And it wasn't just the receiver/tv screen displaying the number wrong, the number on the watch face was that low. VERY STRANGE. I hope someone can shed some light on this.
