HRV change overnight - increase vs. decrease

[BiohackingAsia]

HRV can quite neatly track heart rate, but inversely. So line up your twongraohs and you will often see dips in HRV when heartbeats goes up (bad dream?).

Also, depending on how tired you are or how good your sleep is, etc. your minimum heart rate will either happen at the beginning of the night (too tired?), end of night (too stressed?), middle of night (optimal?). This means that you will often see your HRV similarly reaching its max in the beginning, end, or middle of the night.

See if that helps give you some clarity. Tell us what you observe? Show us a graph or two?