Funny HR data on indoor rides, actual vs planned duration incorrect


I have noticed that on my indoor rides my HR is showing as zero for some periods and I assume the duration is being adjusting as a result. I cannot tell it the avg HR is being affected too. Below is todays ride which was 57 mins long but has been evaluated as 37 mins long. This is not happening on my runs and these dropouts are not showing on Garmins site, also shown below. I am using a Forerunner 265s for all my workouts.

The AI comments noted that my workout was 20mins shorter than expected so I am also worried that it will be adjusting my training incorrectly assuming I am always shortening my rides.



Garmin screenshot from the same workout.

Hey @LukeSL ,
Thanks for that. Can you please also provide here the equivalent Garmin Connect graph and I can take this issue further with our dev team.

Hi Paul,

This is the screenshot from the Connect web app.
I also have the tcx file if you need it and have a way for me to send it over?

Just to say Paul, I’ve noted this recently for my workouts as well. This is Sunday’s workout but it’s occurred on days before as well.

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Thanks @LukeSL … have added that to a bug report and we’ll investigate.

Thank you. Do you know if this may be affecting the plan and if there are any potential workarounds I could try?

Hi @Prof,

I completed another indoor ride with a chest HRM and did not get any drop outs in either the Garmin or athletica data, shown below.

I am still worried that the drop outs may be affecting how the plan is created. Is there anything I can try as a workaround, maybe reimporting the data direct or from Strava?


Great that the chest strap prevents drop outs. To me that suggests you should aim to use chest strap whenever possible?

Hi @Prof
Unfortunately I have just borrowed the chest strap. It also does not explain why the data looked okay on Garmin connect but not on Athletica?

Yes - we’re looking into this @LukeSL but a mystery for us at first glance.

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