Charge 5 Inaccurate Heart Rate

[Shanna79]

I bought a Charge 5 for Christmas. First it was great, but now a month later the heart rate is become more and more inaccurate. I just got back from the gym. I walk/ran on the treadmill. I walked for 3 minutes and ran for 2 minutes off and on.  I started checking the Charge 5 against the heart rate on the treadmill. Sometimes they were within 5 beats of each other and other times they were over 50 beats apart. When I was running the treadmill said my HR was in the 160’s and the Charge 5 said it was 120. I took the watch off, cleaned the back with my shirt, I used the settings and restarted it, but it kept giving me inaccurate readings. I’m very disappointed. I feel like I bought a $200 watch that is only good for counting my steps. 

[Bike-man]

Have you taken your pulse to check accuracy?  I would not rely on the treadmill being accurate. 
I’ve had good results comparing mine to taking my pulse as well as a separate ECG device.  

[Shanna79]

Well yeah, when I’m running on the treadmill and I can barely breathe I’m pretty sure my HR is above the low 100’s bpm my watch is showing. 😉

[Bike-man]

Yep, I hear ya. I cycle. During my rides I approach my maximum HR. The Charge 5 reflects this. Perhaps there may be an issue with your watch. These devices are not always spot on accurate but they should be close.


Joe H.
Sent from my iPad

[Shao3000]

It's the same issue for me, my main activities are elliptical and martial arts, and it regularly drops to lower readings around either 80-90 or 120-130 bpm when an on chest monitor is showing 150+.   It's like accuracy the accuracy drops off a cliff for periods of several minutes, and sometimes barely tracks the high rates at all.   The lower rates still show fluctuations, but not reflecting reality, (e.g. might be get even lower while heart rate on the main monitor is going up).

When these drop outs happen the Charge 5 will one second be showing one heart rate of 160+bpm, then in the blink of an eye will instantly jump down to 90bpm.  Yet when viewing the heart rate for that exercise through the app, the line is smoothed so that a jump like that is shown as a smooth, natural looking decline over about a minute.    Someone who was not continuously monitoring the heart rate on the Charge 5 vs the heart rate from a known accurate monitor might never be aware of the dropouts due to the smoothing on the final output.

On activity recovery days where I limit my heart rate to ~150bpm during elliptical workouts, then the the tracking is often accurate throughout the whole workout, within a few BPM of the on-chest heart tracker.

From what I can tell, it's mostly above about 155bpm that these accuracy drop outs start occurring.

[Bike-man]

Are we expecting to much from a wrist device? I throw this out there as there are a number of things that can impact accuracy. Loss in skin contact, motion artifact, skin temperature, just to name a few. As one who conducts cardiopulmonary exercise studies in a hospital setting, I am aware that even the most sophisticated devices can sometimes show discrepancies.
I use the charge 5 as a means to obtain rough estimates and trends. For me, during cycling, the heart rates seem fairly accurate but my arms and hands are in a fixed position while riding. So perhaps the lack of motion and consistent skin contact account for my positive experience.
That is not to dismiss your experience. Just sharing my thoughts.

Joe H.
Sent from my iPad

[SunsetRunner]

I think you pretty much nailed it there.  I find that most of what I class as inaccurate readings tend to happen if

1. I run in the cold (-2 to 2 deg C)

2. I don't have the device far enough up my forearm

3. I forget to tighten the strap before a run

Once I warm up after about a mile and I've made sure the strap is tight and the device is about 2 fingers above my wrist bone, it seems to settle into the HR I would expect from the pace I'm running at.

[Deakinspeakin]

I get inaccurate readings from charge 5 on my treadmill and stationery bike when holding the grips on either. The readings are either mostly too low, below normal resting rate, or 2x what you would expect. If I ride on the bike hands-free or don’t use the bars on the treadmill then it seems to track heart rate reasonably. So maybe there is some sort of electrical interference that cause the problem since the bike and the treadmill do have built in heart rate functions, though neither has worked for some time (no readings). 
Quite disappointing this.

[IsaacMcLain]

I'm having the same issue. On the elliptical going hard for 45 minutes it goes from 150 to 80 back to high then back to low. I'm trying to get into a prolonged cardio range and maintain it but it jumps so much it's not really doing what I expected it to do.

Has anyone found a way to fix this issue?

[Kinglet]

I have this issue on my Charge 5. My pulse went from 72 to 136. I put my wife's on the other wrist, (also a Charge 5), and it said 69. At the same time I had my finger in a proper nurse's pulse meter and said 68. My device keeps doing this out of the blue.

I was advised to buy a device following two emergency heart operations. I decided to buy a Fitbit because I assumed the results would be more rleliable than the alternatives. It turns out that a Fitbit is a complete waste of money!

[air2raley]

Complete waste of money.   I've been with customer service many times to no avail.   HR is so inaccurate its unbelievable. I hate it.