As a cyclist with an Apple Watch (currently a 7), I’ve notice that the watch actually avoids taking HR readings during rides. I’m using much better devices to record rides (Garmin Edge 830, chest HR belt, other ANT+ sensors) anyway so I don’t really mind, but I do notice the gap in my HR readings in Health. I’m not at all interested in sleep tracking (tried once with a Withings Pulse, didn’t find the data at all useful), stay as far away as possible from the rings. When cross country skiing, which I’ve had a chance to do quite a bit in the last month, I leave my Apple Watch at home and use my Garmin Fenix 5+.