Falsely High Initial Heart Rate Readings

Roadracr wrote:

This is an interim update. I wanted to follow your guidance on turning off the HR data from my AirPods Pro 3's and try another run just to see what happens. Today I did that and went out on a 5 mile run and checked the data upon my return. The good news: no erroneous HR spikes. The bad news: no HR data at all for the first 15 minutes. ¯\_(ツ)_/¯ . I'll try that again on my next run, then I'll contact Apple. My initial interpretation is that the two data streams from the Watch and AirPods combined in the early going, but I don't have an answer for the missing early data with the Watch alone.

Reading carefully all the information you have reported, here are some inferences as to what may be going on:

• Getting pulse data from both the AirPods and the watch sensors might lead to higher heart rates because the watch is getting heart beat information from both its own sensors as well as the AirPods and the AirPods data are arriving a bit later due to coming via Bluetooth. The combined stream might "look" like multiple recordings of the same heart beat and hence a falsely higher rate.
• With my own Series 11, I have noticed that (a) if there is not correct and good contact between the wrist/arm and watch, the initial pulse readings can be delayed while the watch searches for a signal; and (b) when the signal is found, it often starts "high" and then ratchets down to a lower final stable reading. I have a fairly low resting pulse, in the low 40s, but when I start a reading it shows immediately a number like 50-60 and then comes down rapidly to, say, ~ 43. I believe this is a "feature" that may be related to the algorithm being used.
• Based on (a) and (b) above, if the watch sensor intermittently loses good contact with the wrist/arm, then it may lose the signal for a second or two (or several seconds) and then "starts over" with a new reading when it regains the connection. This might start out at a higher value and then come down to a stable steady state value. When looking at the session, this might look like "spikes" in pulse are sometimes occurring. But it might be a combination of periodic loss of signal plus the conservative algorithm that starts on the high side and stabilizes at the lower steady state value for pulse.

Key to avoiding this might be special attention to good skin/sensor contact with the watch, making sure the watch is not too close to the wrist (e.g. is a bit further away up the arm, a fraction of an inch may be all that is needed), and also making sure that the sensor is centered on the arm, not facing out on the bone (the bone does not provide good contact). Different watch bands work better for this than others, for each individual with their unique anatomy. Most people seem to choose a watch band for esthetic reasons, but other watch bands may enable better contact for health and sports monitoring.

Since the Apple Watch Series 12 and watchOS 27 just have been released, this might be a software issue.

To find out, if your AirPods Pro 3 interfere with the heart rate readings of the Apple Watch, try to disable the heart rate measuring feature off as a test. Then start your usual workout and check the heart rate at the beginning.

...

Heart rate monitoring is on by default. To turn it off:

1. Put your AirPods Pro 3 in your ears and connect them to your iPhone.
2. Go to the Settings app on your iPhone, then tap the name of your AirPods.
3. Turn off Heart Rate. If Heart Rate isn't displayed, first tap Privacy.

...

When you wear both an Apple Watch and AirPods Pro 3 during your workout, they work together to provide you with multiple streams of heart rate data for even better coverage. The highest confidence source in the moment will automatically be used to provide heart rate data.

...

copied from: How to check your heart rate with AirPods Pro 3 - Apple Support

Also make sure that you wear your watch approx, 2cm further away from the wrist as usual when starting a workout, so that the watch can get a proper reading right away.

I remember, that my old Series 5 started the detection of the heart rate like a count down from the last recorded value,

downwards, until the current heart rate had been found by the sensor.

Roadracr wrote:

I was waiting for another run with my AirPods Pro HR turned off. This time I got a relatively high initial heart rate reading (140-145bpm) for the first minute, then no HR data for the next five minutes, finally registering again at the six minute mark at about 120 bpm, which was about right, given the easy run I was on. I've made no changes to my wrist location and the watch seems to always read correctly while I'm sitting or walking around. I do wear the basic sports band which holds pretty snugly.

What you describe sounds a lot like the skin contact is not consistent during the workout, leading to large gaps and then when the signal recovers and is detected again, it tends to "start" high and adjust downwards. You should not be seeing those gaps of ~ 5 minutes ... my Apple watch (Series 11) has no gaps during workout.

The watch can work fine when walking or sitting but during a running (or for me, bicycling on surfaces that can be bumpy) workout the watch is bouncing around or being jostled some, versus when sedentary. So that's a classic sign of gaps caused by imperfect fit or just not having a good match to your anatomy for the band you are using.

Now with what I've found, with and without using the AirPods Pro HR monitoring, I'll reach out to Apple and see if they have any ideas. If all they do is tell me to readjust my watch strap I'll be disappointed.

But what you describe does indeed sound like an adjustment is needed for the watch band/strap. It works fine when sedentary but with workout bouncing/jiggling/shaking motions it isn't maintaining the contact with the skin that is needed for continuous heart pulse measurements.

thorstenboer wrote:

- Then no data at all for 8–12 minutes (8.3 / 8.9 / 12.2 / 11.5 min)

This indicates that skin contact for your watch/sensor/band configuration combination is not working for your arm/wrist anatomy. Regardless of what worked or didn't work with other watches in the past. My watch (Series 11) records heart rate on outdoor walks and outdoor cycling workouts continuously without gaps. It is not every 5 seconds, but rather every 20-30 seconds or so, which seems adequate for my needs. But there are no gaps. I found when I first got the watch that if the band is too loose, there were gaps. I use the simple standard rubber band. After tightening it one notch and centering it better on my wrist/arm, it works well.

- HR coverage: 44 % / 27 % / 7 % / 29 % (before the restart: 47 / 47 / 26 / 18 %)

This should be 100% for every instance. Skin contact here is intermittent for you.

A core workout without running showed no start error at all.

Running creates quite a bit of jostling and bumping which can interfere with good sensor/skin connection unless the band is right and is tightened properly.

It's about Apple's claim that made me upgrade from the Apple Watch Ultra 2 to the Ultra 4: that the sensor now measures heart rate every 5 seconds and is more accurate. Given this experience, the upgrade has been pointless for me.

I see how this can be frustrating. But one has to have very good sensor/skin contact for the heart rate detection to work reliably.

I think the fact that you have gaps indicates that the heart rate is being detected intermittently instead of continuously. In case there is an issue with the watch hardware itself (versus its fit to your anatomy), you could have it examined by an Apple Authorized Service Provider.

I have the same problem.

I have recorded 14 outdoor runs (easy pace, 6:20–7:50 min/km) and analysed the exported workout files second by second. The same pattern appears in almost every run:

1. False high values at the start: during the first 20–60 seconds the watch shows 120–155 bpm (13 of 14 runs). My real heart rate at that point is around 80–90 – the first plausible value after the gap is usually ~84, then rising normally to ~100–110.

2. Long gap right after that: no heart rate data at all for 2 to 11 minutes.

3. Many shorter dropouts during the rest of the run (20 s to 5 min).

4. Frozen values: in my latest run the watch showed exactly 140 bpm for over 30 seconds while I was standing still, and 165–166 bpm for 12 seconds at an easy pace – a few minutes later 82–101 at the same pace.

Share of seconds with a heart rate value, run by run: 84 % → 73 % → 43 % → 37 % → 19 % → 58 % → 74 % → 47 % → 47 % → 26 % → 18 %.

What I have tried:

- Band tighter, watch one finger above the wrist bone (helped once, not consistently)

- Outdoor Run workout, no external sensor paired

Interesting detail: my previous Apple Watch Ultra 2 showed the exact same false start values in all 3 runs after updating to watchOS 27.0 – but never in 2025 on watchOS 11. So I suspect at least the start problem is software-related, while the growing gaps may be specific to my unit.

I’ve gotten (false) double-rate heart rate readings on occasion from various Apple Watch models over the years, when exercising. Jogging, trail-running, various quick sequences, etc.

I see if the count matches a manual carotid or radial pulse check when stationary, check the strap tension, and then ignore the readings.

From time in emergency medical services, cardiac monitors and heart rate monitors and other meters never worked entirely reliably when used in the back of a speeding ambulance on a rough road, either. And some automated cardiac rhythm recognition systems would misdetect rhythms, too. We’d preferably save recordings (“mark”) or would print cardiac rhythm strips only on sections of smoother roads, and even then some artifact was to be expected. So-called “road rhythm” was (is) a thing.

Or as was succinctly put during many EMS training sessions, treat the patient, not the meter.

PS: I do use bands that are elastic and velcro and fit-adjusted when exercising, and not any of the looser bands.

Interestingly, I just came across this post about an Apple Watch 9 user, seeing similar heart rate reading issues:

Apple Watch Series 9 reports erroneously … - Apple Community

So for me, this look more like a watchOS software issue, and you should also report this to Apple Techs directly by using the Feedback link:

Feedback - Apple Watch - Apple

This is an interim update. I wanted to follow your guidance on turning off the HR data from my AirPods Pro 3's and try another run just to see what happens. Today I did that and went out on a 5 mile run and checked the data upon my return. The good news: no erroneous HR spikes. The bad news: no HR data at all for the first 15 minutes. ¯\_(ツ)_/¯ . I'll try that again on my next run, then I'll contact Apple. My initial interpretation is that the two data streams from the Watch and AirPods combined in the early going, but I don't have an answer for the missing early data with the Watch alone.

I was waiting for another run with my AirPods Pro HR turned off. This time I got a relatively high initial heart rate reading (140-145bpm) for the first minute, then no HR data for the next five minutes, finally registering again at the six minute mark at about 120 bpm, which was about right, given the easy run I was on. I've made no changes to my wrist location and the watch seems to always read correctly while I'm sitting or walking around. I do wear the basic sports band which holds pretty snugly.

Now with what I've found, with and without using the AirPods Pro HR monitoring, I'll reach out to Apple and see if they have any ideas. If all they do is tell me to readjust my watch strap I'll be disappointed.

Update (10 Oct):

4 more outdoor runs after the restart:

- False start values every time: 123–138 bpm in the first minute (actual approx. 85–95)

- Then no data at all for 8–12 minutes (8.3 / 8.9 / 12.2 / 11.5 min)

- HR coverage: 44 % / 27 % / 7 % / 29 % (before the restart: 47 / 47 / 26 / 18 %)

When the watch does record after the gap, the values are plausible (90–110 bpm at an easy pace). A core workout without running showed no start error at all.

So far: start error in 17 of 18 runs, still on watchOS 27.0.1.

This is not about using a chest strap or similar – it's obvious that works fine.

It's about Apple's claim that made me upgrade from the Apple Watch Ultra 2 to the Ultra 4: that the sensor now measures heart rate every 5 seconds and is more accurate. Given this experience, the upgrade has been pointless for me.

Thank you so much for both of your helpful replies. I doubt this is a WatchOS 27 problem as I had it with my Series 4 previously. However, your suggestions and instructions for turning off the HR monitoring on my AirPods Pro 3's and see how that works. I'll also report to Apple directly. I really appreciate you making the effort to assist. I'll provide an update if/when I get to the bottom of this.

Thanks again. I don't think skin contact is the explanation, though:

- Same band, same fit: once the watch has "found" the signal, it records continuously. On a 53-minute outdoor walk it recorded 40 minutes almost without a gap (only one 42-second dropout) – right after the initial gap at the start.

- The problem shows up mainly on outdoor runs. On outdoor walks it hardly occurs apart from the start.

If the fit were the problem, I would expect gaps randomly throughout every workout – not this pattern.