I have been diagnosed with both IST and POTS. My resting hr is 100-120 during sleep. It only goes higher with any activity, standing, walking, etc.. I am unable to tolerate any meds, the only thing I take is an SNRI to help raise my BP which stays between 90/60 which is good for me to 60/40 . I am completely disabled since 2008 from this, but have had it my noire life. I became significantly worse in 2002