I use an Apple Watch 5 and the Strava app to track my activities and everything works fine -- distance, heart rate, etc. shows up every time and seems basically correct.
I recently started cycling. The tracking works fine, but for some reason there's no heart rate data -- that section of my cycling activities says I should use a heart rate monitor if I want heart rate data. Why would this be happening? Do I need to somehow switch "on" the heart rate data for cycling somewhere? (The heart rate data is still showing up for running, and when I look in Apple's native health app, I can see that the watch has recorded heart rate data while I was cycling, so it's not that the watch is not recording it.) Thanks!
P.S. And yes, I have the most recent version of the app.