This remains the single biggest ‘alert’ for me after doing this stuff for a couple of years now - and it’s why i like having HR on the screen for workouts to help me be objective as well as how I ‘feel (RPE)’. Doing something about it is often hard, but it does work (listening to oneself)
HRV is one thing I’ve been keen on for a year, though I’m having real trouble trusting it on an iPhone use HRV4training. Sill looking for that elusive, easy to use, reliable(consistent) HRV monitoring device