Different data recording per sport activity

Vizi said:

go there every time I activate different sport activity,

The setting is global.  You  can't apply a deferent setting per activity.  Set it to Every Second and go about your life in happiness

Right. I don't understand why does smart recording still even exist? The supposed storage savings it provides is likely negligible compared to how much storage modern devices have. But it causes perceived lack of accuracy when users look at saved tracks and see the lower resolution. Also it causes issues with 3rd party services like Strava (e.g. inaccurate matching of segments) for which Garmin is often blamed. At the end, negatives outweigh positives. 

Thank you for answers. 

Does data recording setting affect HR accuracy or just GPS accuracy?

It isn't supposed to affect accuracy at all, meaning that the watch still polls GPS position updates every second regardless of this setting. However it affects which data samples get stored to the watch storage. With smart recording some samples get discarded.

I am am not sure whether it affects HR data or not, but that is very easy to check by exporting your activity as a GPX or TCX file and just looking at it - these are text based formats. You should be able to see whether HR samples are every second or not. 

silentvoyager said:

I am am not sure whether it affects HR data or not

https://support.garmin.com/en-US/?faq=s4w6kZmbmK0P6l20SgpW28

I read that before posting but am still not sure whether it affects HR accuracy or just GPS accuracy. What do you conclude based on the link that you sent?

So in the end it does affect saved/recorded GPS accuracy at least slightly.

Exporting to GPX and TCX files can be done from Garmin Connect web? Good suggestion.