@Jyoti - I didn't even know HRV went over 100! Mine is always around 30 - 40, sometimes a little higher. The Elite HRV app analyzes my numbers and then gives me a score of between 1 - 10, with 10 being the highest meaning I am all set to have a very good day. And I've gotten a 10 on days that I am crashed! I really haven't found it to be a useful tool . . . I hope you get some answers from others here who are much more knowledgeable about this than me!
I am beginning to think that my high numbers are actually a sign of a heart gone wild on too much adrenaline rather than one floating on a parasympathetic lily pad. I have no idea why or how my body keeps on making and releasing it, but it seems to have an endless supply. I am surmising that in order to fulfill the obligations I have in the world, I fuel myself on epinephrine while my body--without it or underneath it-- is actually in near total collapse.
Experimentws today with meditation and other forms or what we might call mindfulness--just to see what would happen--and it brought the HRV numbers down into a still high, but less absurd realm (86 during meditation this afternoon--from 168 overnight!). Which is exactly the opposite of what meditation is supposed to do. But...we live in a world where standard advice (e.g., get into your cardio zone for at least 20 minutes a day!) can be lethal.
It is mysterious, to be sure. No way, though, that whatever is happening to my heart has anything to do with being in a state of extreme fitness!
Meditation doesn't seem to improve my HRV at all. I eventually stopped doing it as I don't really enjoy it or find any benefits. I kept trying because it's supposed to be so great for physical, mental, etc. Just doesn't seem to do that for me.