Looking at my FitBit data, I can see that at the end of an REM phase (toward the end of a dream) not only does my heart rate slowly begin to rise (~10 points) but during this increase I'm doing something in my dream that would get anyone's heart rate up if it was happening during the day. Things like being afraid, getting emotional (sobbing), lifting something heavy, walking up a steep hill, running, a "hypomanic" episode (which I actually do not generally have during the day). Then, I will wake up suddenly and my heart will immediately spike up to around 110, taking around 15 minutes to return back to around 70. This will happen around 5am and then again around 7am. And it has been happening almost every night.
Just for context, I am aware that heart rates can increase during REM sleep, but I've never experienced spikes like this before, even the 10 beat increase. This is new and different for me. I have no idea if my increased heart rate is causing these dreams or if my dreams are causing the increased heart rate. It's happening so frequently and I'm exhausted when I wake up. Has anyone else ever experienced this and with such frequency?