The watch readings are from when I am not exercising. I have a Wahoo TICKR chest strap for the bike. I watch the heart readings carefully, I track HR vs power and can tell when something is even starting to go off a bit. None of these events are anything major at all, so far it is dehydration / hunger / adrenalin / overheating giving me at most 10-15 bps above what I expect for the given effort.
I don’t know if the supplements are making any difference but I am going to be cautious on everything for a good while here. Once I am in the clear for say six months I will start adding things back. I am also sticking more religiously to “zone 2” training, I think I was doing mainly sweet spot when I thought I was in zone 2, and I was getting pretty wiped out after a 2-3 hours ride. The heart issues on my watch were after such high-exercise rides. I just did 2.5 hours being good about staying in zone 2 and I feel great. I stopped at a coffee shop halfway through and had a decaf cappucino .. easing up on the caffeine a bit as well.