Epix for indoor cycling.

I can't answer that particular question, but what I can say is that I cycle indoors, connecting the Epix - on my wrist - to Rouvy via Virtual Run, and the heart rate is dead accurate. I've tested it against a Wahoo chest strap and an Apple Watch 7 - all at the same time (strap to Rouvy, other two on each wrist). Each was with a beat of each other for a 50 minute segment. For me, not having to wear a chest strap is liberating.

Thanks for your answer.

But it is easier for me placed on the handlebar of the bike when following a training session.

I do the same, I'm finding the stamina screen a nice addition to intervals on the turbo.

To the op, I'm guessing that Garmin will have configured the screen to stay on during an activity given the amount of Tri users who use a handlebar mount.  But I'll try and test that to prove it.

Just tried it, screen stays on.  It goes into dim mode but doesn't turn off in the same way it does when not in an activity

Thanks a lot 

Same problem here. 

The display turns completely off when doing an indoor bike activity. Watch connected to a chest strap and attached to the handlebar. 
The display is set to always on and gesture on during activity. 

any thoughts why this happens ??

Try seeing what power mode you have in settings under the activity.

Thanks. I’ve checked and it’s normal power mode. 
very strange …

I read on forums that it needs to detect some movement when attached to the handlebars to avoid turns off the screen.

All I can say is I've not seen it turn off on my Epix when mounted to my handlebars on an Indoor trainer.  So if it does need movement, it's very sensitive to even the tiniest vibration.