Hi Gang. i am the newbie here. I have been doing strength training but decided to add more cardio . As soon as I did it appears an RBBB showed up so I got the x2 to help me see what is going on along with seeing my cardiologist. It has been interesting the last week as it caught arythmia and spikes in heart strain. However it now appears the RBBB has disappeared or resolved. Did not know it could do that. Looking forward to using X2 to help me do what I do in weightlifting which is progressive overload. Better yet I hope it catches some of these crazy things with my heart rate.