Three weeks ago I wrote a post titled 'Glitch or cause for concern?'Out of curiosity I bought a chest strap heart rate monitor (as many people were saying they are more accurate) with ecg capabilities, and last Thursday the same thing occurred. I actually saw my watch registering 32bpm for several minutes however my HR was 66 and, when I downloaded the reading from the chest monitor, there was no drop in my heart rate.
Personally I feel that these wrist worn gadgets are very useful for general fitness, but they can cause a huge amount of unnecessary anxiety due to their limitations. I certainly have learnt a valuable lesson. I hope this helps other people also.