Tachycardia tips

I know an astonishing number of people suffering from dysautonomia and tachycardia. I learned some stuff from this article (maybe y'all know it already): Mostly about the importance of distinguishing between tachycardia from POTS and from an adrenaline surge, because those are dealt with differently. I wish the tips didn't start with exercise, because I think everyone's getting inundated with, "Have you tried exercise?" (I've been guilty of this too. Sorry!)

On the subject of not-exercise, I've read the "I rested my way to recovery from long COVID" essay, and it's tempting to put stock in it, but there was nothing to distinguish that method of recovery from regression to the mean. That is, the author might have just gotten better in time, regardless. Or they might have had a better chance to recover because their life was privileged enough to allow them to rest. This is why we need data from controlled studies.

Edit: While we lack controlled studies, we may as well pay attention to experts and anecdotes suggesting rest.