Hello everyone, I was wondering if anyone had any light to shed on the question of OI and POTS in relation to M.E. I was diagnosed with M.E almost 20 yrs ago, in my teens. I have struggled with it through bad and better phases ever since. Only recently did I begin to wear a heart monitor. Almost immediately, I noticed a correlation between my exhausted periods and my heart rate rising. It is fast upon sitting, and more so upon standing, moving from 80 at seated to 120 ish upon standing, and reaching 130 or so just standing about the house after 15 mins or so. I started to realise that my seeking a place to sit ,or stopping activities when I felt tired, coincided with a rise in my heart rate. On days when I am already feeling tired, my heart rate is higher before doing anything. I asked my doctor about this - she said there was a difference in sitting/standing, and that it was high, but not dramatic. I wondered what anyone else's perception of this might be! Does this sound like a familiar profile to any of you? Would it suggest that I ought to raise the question of OI with my GP again?