HRM with "NaN" values when exported to Strava

Hi all,

Despite during the workout the Heart Rate performance is consistent showing continues values, when workout is transferred automatically to Strava it can be seen on the Strava chart and average values a lot of spikes down decreasing the heart rate performance.

When looking into Sufferfest csv file of the workout (heartrate field) I found more then 1/3 of the samples have value “NaN”.

I already restarted the PC, changed my HRM-Dual battery, monitoring the Bluetooth connection and not able to understand the problem.

I must say that I have done 10xworkouts and first 3xworkouts didn’t shown this problem always the latest ones. The homeplace setup was always the same.

I am not sure if exists any settings that allows not to send to Strava the “NaN” values.

Thank you in advance for the support.


Hi @Nuno_Gouveia
Check out step two in this help article. I’m wondering if you just need to give permission for Strava to use your heart rate data.