heart rate anomaly - a problem or within the bounds of normal?

I'm a little short of time right now so I'm posting these two images and I'll return to post further text later:

First a NORMAL trace for an interval run:

 Secondly the ANOMALY trace:

 I think it's obvious what my question / concern is, but I'll be back later to add detail or respond to any questions raised. Any constuctive comments in the meantime would be much appreciated.

 

[@cicerunner]

You've run over a buried electrical cable or over a railway line. I had a place across a golf course where I could register 240 bpm.

I registered over 210 for the first 4 mins of the race yesterday.i think it was the starters gun that scared me shitless

Thanks people. My first thought was that it was a recording error. Perhaps the buried power cable is the source ... I'm running in a built up area. No train lines.

Over the period that I've worn a HR monitor there have been perhaps half a dozen occurrences like this. In the early days I just had a watch that gave two figures - max HR and average HR and it was easy just to throw away the first figure and assume it was an error.

Now that I have access to traces and I'm getting a little older I am being more cautious. Having said that I have zero symptoms of any kind during the run and wouldn't have known about the anomaly without seeing it in the HR trace.

I don't have GPS built in to my watch, but may carry my iPhone with me for a few runs to see if there is a geographic location which regularly produces this.

My HRM sometimes has a high reading up to 250 bpm but this is usually at the start of a run and jumps up and down inconsistently with my pace; I assume it is due to poor contacts. Your heart rate seems to increase consistently with your increase of pace? This would suggest that it is a true reading, BUT, do not assume that your HRM is accurate! You say that you have no symptoms, that suggests this is not a problem for you. But this does seem high; try checking your pulse and see how close it is to your HRM readout (I know this is easy to say) or maybe borrow another HRM and see if it gives similar readings?

If your heart had jumped - you'd know about it.  My HRM used to blow out the max once every 10 runs/rides or so. 

If your heart rate looked like the speed graph it might be a problem but looks  quite even aprt from the one spike which is most likely a recording glitch perhaps from poor contact.

Hard to say based on just that one spike, especially as it drops right off as soon as you ended that interval. I have a top end Polar monitor which captures every heart beat and its somewhat easier to distinguish bad contacts from the data - but only when you are back home and have the data uploaded. If I see a dodgy looking high reading before commencing an interval I tend to fiddle with the strap until I can convince it to settle down again, and/or stand still for 30s just to be sure. What hrm and more importantly which strap model do you use? Is it one of those horrible plastic moulded ones or more fabric based? Did you have a fair amount of sweat going at the time? Sometimes just pressing down on the middle part of the strap can correct contact problems but the're more common in the early stages of a session. The ultimate contact is to use electrode gel, but you do have to spend more time cleaning the belt afterwards otherwise that can affect it too.

I always check my hr just before commencing each rep just to make sure I'm recovering properly, as the session goes on you might find its not returning to jog level anyway. If I'm on a steady run I may well ignore an anomalous high reading but during a rep session when you are maybe hitting max hr I prefer to not take chances as your heart is under so much more stress.

It could be real - as opposed to a HRM glitch but before reading further: don't panic! Exercise induced atrial fibrillation (AF) does not appear to be very uncommon (think also palpitations) though I'm sure severity of individual experiences will vary wildly. It happens to me fairly frequently though I suspect I'm older than you and it becomes more common as you get older. I'm very rarely aware it is happening at the time unless I'm regularly looking at my HRM* It's usually very transient and more likely to happen early in a run, usually though not necessarily at the start. Since I've been aware of it happening for a few years now I'm more attuned to when it is likely to happen and it will usually go away after a few cycles of run-recover. I always go through that as a pre-race warm-up now because if the AF does last for quite some time I get much more tired later in the race. Worst in a race was a HM where my HR exceeded my normal max (without me knowing) for the first five miles or so and then normalised but by that time the damage was done and by mile nine I was shot and had to run-walk to the end. I've only once had a more severe problem where my HR didn't properly recover when I stopped to walk and I stayed in AF, though again feeling perfectly well at rest (I was unusually breathless when attempting to run on that occasion.) That was finally fixed with drugs after an overnight hospital stay. On two hospital investigations now I've been through ECGs, exercise cardiograms and ultrasound scans and all has looked normal. Keep an eye on it, keep your traces and if it becomes more frequent or you are worried go see a doctor. Alcohol, caffeine and doubtless many other drugs can be AF triggers. Search on 'atrial' / AF / fibrillation / tachycardia in these forums and also look at the Cardiac Athletes website and you'll see that even if it is AF and not just a HRM glitch there is no need to stop running.

Lots of really thoughtful feedback. Much appreciated people. Will pursue each possibility in turn as I rule out the previous one.