Discussion: All psychological? ;)

Did you notice the increase in HR? Certainly my monitor does that every now and then but IM sure its the monitor on the blink. Assuming you could feel it though it is strange that it happened not long after you started using your HRM again. Re-focussing on the HRM and your HR while running must have played a role?

Could have done - certainly feel psychologically impaired at times :-). But have been running fine with the HR monitor before, including interval training. Anyway, this problem has been dogging me for over a decade (and through several different HR monitors - I also blamed faulty equipment, but I must say that when it happens it really knocks me around). It finally got diagnosed properly a couple of years ago at the American Hospital in Paris. Exercise-induced arrhythmia. Pretty scary the first few times it happened - thought I was having a heart attack. Succession of doctors in Oz and Paris dismissed it or couldn't find anything. Was getting worse two years ago and so managed to get an appointment with a couple of top flight cardiologists who took it seriously. Put me on a treadmill and ran me to exhaustion and sure enough, the HR went apeshit under stress, right on cue. No identified cause but likely to be an electrical misfire under stress or when run-down. No real cure (except for pacemaker, which is a bit of overkill, or not running at all, which is not an option :-)), but stopped caffeine and alcohol, increased hydration, drank more electrolytes, and tried (and largely failing) to get more sleep. Has worked so far, and on the occasions when it happens I can usually pinpoint the factors that contributed. Anyway, long explanation :-).

makes sense. have a look sometime at Craig here on attack point. His full name is Craig Dufty and he's WA based orienteer. He has a lot of trouble with it and relatively recently had some sort of surgical procedure to get it right. i haven't been following him on AP so much so not sure how it went. can't imagine it would be good having our HR explode upwards like that! It does happen to me but its just my HRM giving dodgy readings! :)