Yeah, I first learned that from the "HOW TO SKATE A 10K" ebook[0] that was posted here[1] a while ago. He talks about how he tracked heart rate to figure out when he was going to get sick.
I then started looking back at my historical garmin data, pretty much everytime I was sick, my HRV would drop a few days before. I then started monitoring my HRV closer and taking it easy whenever it dropped. Anecdotal data from one person here, but I found that I get sick less and when I do get sick, it's usually not as bad.
Yeah HRV is especially good for that. Mine doesn't really expose HRV very well, I'm guessing because I'm a couple of generations back, so I have to make due. Works pretty well even so though.
I then started looking back at my historical garmin data, pretty much everytime I was sick, my HRV would drop a few days before. I then started monitoring my HRV closer and taking it easy whenever it dropped. Anecdotal data from one person here, but I found that I get sick less and when I do get sick, it's usually not as bad.
[0] https://www.howtoskate.se/
[1] https://news.ycombinator.com/item?id=30320639