COVID Diaries - Heart Rate Running

In one of my FB groups today, I posted this, but it belongs here too:

Y'all, I think MAF saved my life. 
Sort of?  Maybe not quite that dramatic, but MAF training has been important in resolving a significant health issue.
Around February, my physician recommended changing medications, explained the pros and cons of this med, and I took her recommendation.
A day or two after that, I headed to Florida (from Minnesota).  Running was fun, but my heart rate was a bit higher than I expected.  Whatever right?  It's winter where I live. I'm hot.
It just kept going.  As changes with COVID and... my heart rate just got worse and worse.  I assumed it was stress. And the changes in life, and my crap diet under quarantine.
Last week I had a scheduled check in with my physician about the new medication.  I told her "the side effects I had with old medication are gone. With new medication, when I run my heart rate is so much higher than I expected it to be.  I used to be able to run at this pace at 140bpm, and now I'm at like, 160 bpm.  Also, I can't walk up stairs in my house without getting out of breath."
Unrelated to MAF, I was able to take my blood pressure and it was crazy messed up. 
I had a virtual visit with my physician.  She said "I did a lot of research on this and this medication can cause tachycardia in 4% of people, so I think we need to stop it"
And then my physician said "you should be feeling better within a week".  I was like "really?!?  I've lost all my fitness". Literally, I can't walk up the stairs in my house without getting out of breath.
Y'all, 2 days later, I'm almost back to being able to run at MAF again.   It's amazing.
It was so important that I was able to say to my physician "I wear a heart rate monitor when I run.  These are my normal number and this is what it is now."  The data helped her quantify the problem. It's a rare but documented side effect of that medicine.