Hi Joky;
I wish I had answers for you, but I have only questions.
What kind of testing did they do? Anything under stress like a 6 minute walk test or a stress test?
I’ve read that it’s normal to have o2 levels drop while talking, but I don’t know by how much. The heart spike is interesting; it makes sense that hr would increase if o2 levels dropped since the heart would be trying to pump oxygen rich blood around the body, but 120? I don’t know.
The car situation I don’t know either, unless there just wasn’t enough fresh air coming in. Plus, you were sitting still.
Have they checked you for something like POTS or dysautonomia? Not sure why, but that comes to mind. Maybe the heart spikes while talking and maybe sitting still, and while sitting still in a car. I don’t have pots, but I’ve read it can happen while sitting upright.
I’m no dr, just telling you what occurs to me.
I could be completely off base, but maybe this helps.