Hey all. I’ve noticed, for a long time now, that when I am riding pretty steady on the trainer I will all of a sudden have a 10-20 bpm drop in heart rate for seemingly no reason. I feel no different physically when this happens. I have tried to blame it on cadence changes, elevation changes, power changes, sitting up, drinking water, talking, not talking, etc., but none of these seem to explain these random dips that seem to happy at consistent intervals. I had it happen during the LTHR portion of the Half Monty test on Sufferfest and got a message saying “keep your heart rate consistent”, in which I wanted to reply, “I am!” I can not think of any confounders other than blaming it on a glitch in the heart rate strap. For the record I have seen this happen on my old Wahoo Tickr, my newish Wahoo Tickr, and my newest Wahoo TickrX. I often switch between my Tickr and TickrX and it happens regardless of which one I use. I am including some screenshots to show you the dips I am talking about. I was wondering if anyone could think of a physiological reason why this is happening or if any else has noticed similar anomalies with their heart rate or perhaps with Wahoo specific heart rate straps. Thanks!
Hi @murphyy12, thanks for posting and including those examples. I’ve seen a lot of anomalies personally and from my athletes over the years, but those are quite interesting. The regularity of them is really what stands out to me. They seem so rhythmic in both frequency and amplitude. It seems like you expended all those “usual” causes of cadence, sitting up, passing under power lines, jersey flapping, etc. And the fact that you’ve experienced this with 3 different HR straps is very interesting. So the physiology brain in me starts to think about the heart. There are certainly a number of anomalies with that conduction system that can lead to all sorts of changes. I’m not going to claim any expertise in that area right now because it’s been many years since my ECG coursework, but will just suggest that going through that process of an exercise stress test might reveal more. Have you already thought about digging any deeper like that?
Thanks for sharing!
Coach Ryan
As odd as it sounds, I have a consistent dip in HR when I burp. You can see it on this chart as the highlighted ‘V’-shaped drops.
I’ve had it for as long as I can remember and it happens regardless of HR sensor, so it’s clearly physiological. I don’t think it’s ever skewed my data analysis.
I’ve searched previously, but never found any information on it. However, a quick search this morning revealed this: https://www.internationaljournalofcardiology.com/article/S0167-5273(10)00238-X/abstract
I’m reluctant to read the full text: it will probably tell me something really bad is going to happen!
Are you doing something, seemingly innocuous, like this when those drops occur?
@ryan thanks for the reply. I have done EKGs on my Apple Watch which always show normal sinus rhythm, but I understand there are limitations here. I’ve not thought about getting a more in depth work up because of course I feel normal so the knee jerk reaction is “there’s nothing wrong!”
@davidmosborne that is really interesting! And for there to be literature on it is quite something. I will pay even more attention to see if it is something as strange as that. But I do pay pretty close attention and when I see the HR start to dip I will really focus on every little thing that my body is doing or what I am doing to see if it can explain what is going on. I can literally see it happening on screen. My HR will go down 1-2 bpm every couple of seconds until it hits the full 15-20 bpm drop, then it will start going back up at the same rate until resting back where it started before the drop.
@murphyy12, the ECG feature on the Apple Watch is pretty cool. I actually found an article previously where a Physician compared a 12 lead ECG with various positioning options with the Apple Watch and you can get singular reads on different leads essentially. So it’s really cool - for example, you can take the watch and place it over the heart (just lay the watch flat over your chest) and then use your right finger (like the standard method with the watch on your wrist) and get another read on the rhythm. I think maybe V3, but can’t recall exactly. Anyway, it’s pretty amazing what you can see with the tech!
@davidmosborne, very interesting article you pulled!
Coach Ryan
We’re you able to get the full text?
@davidmosborne, I’m not sure if/how I can upload a file, but will try posting the photos of the article here. It’s only 3 pages, so pretty quick read. Hope that helps!
Ryan
I know it’s been a year, but I determined that my HR dips are indeed only when I am burping!!! I discovered this for certain many months ago, but just kept forgetting to post it here. Not sure what it means, but there we have it…bupring = HR drop.
I would consider it feedback from mother earth to stop drinking soda 
Very cool that you posted your conclusion!