I learned here from various folks including SOC what a pulse pressure is and how to calculate it. Which is a good thing because I was feeling kind of terrible all of a sudden today, just sitting at a desk, and took my BP. In series here is what I saw this afternoon: Time / BP/ PP 1:59 106/85 @ 95BPM, seated, Right arm, Pulse pressure 21 2pm 116/86 @ 92 PP 31 2:01 107/85 @88 PP 22 2:02 113/82 @91 PP 31 2:03 104/81 @ 89 PP 23 <-- This was the first time I've ever seen my BP monitor display the little shaky heart symbol, showing an unstable beat/contact your doctor message (whom I will be seeing tomorrow). by 3:30 I was consistently back up at like 122/86 @ 84 BPM, PP 36 I read in wikipedia that anything under 25 is, well, bad. I've seen PP as low as 27 or even 25 but never 21. For POTS/OI I've been dosing salt and occasionally using the electrolyte drink SOC had recommended, but I didn't use it today. This actually started out as good heart rate day (didn't see any early morning tachycardia like I usually get). My cholesterol is crazy high but I don't think that should affect pulse pressure. I have had a history of occasional atrial fib, and think I had a brief episode of that as recently as last Sat night. But this didn't feel like that, e.g I didn't feel the usual "limbs going to sleep" feeling of the afib. Anyone else deal with periodic pulse pressures this low? Any ideas? Things I should ask the doc tomorrow?