My parasympathetic system is rarely active during the day. Initially I had nothing to compare my HRV levels with, but since my husband and mum both started tracking their HRV, I've realised their parasympathetic nervous systems are activated so much more than mine (and that is despite my husband suffering with anxiety!). The difference is quite staggering.
I wish I knew what my HRV used to be before getting sick, to compare. My sympathetic nervous system and stress levels rocket during tasks that surely shouldn't take that much energy.
Interestingly, when I'm in a crash, my parasympathetic system is much more active. I read somewhere that if you've pushed yourself too far, your body can basically force itself into recovery mode. I think that's what happens in my case.