While hunting monsters, I've noticed that a pseudo-heart rate monitor is displayed when the monster is nearby.
While fighting them, I've tried to keep an eye on it to try and understand what it indicates, but I haven't been able to figure it out.
Sometimes, the heart rate spikes and flashes orange, while other times it slows down and stays blue. I'd originally assumed it flashed orange and spiked when the monster was dying as it was fighting for its life, but this hasn't always been true; sometimes it's quite slow even when the monster is limping.
What information does the heart rate monitor tell me? How should I interpret the display?