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I think the conclusion is more that POT may not be relevant to the symptoms POTS patients experience. Orthostatic tachycardia seems to have a very weak relationship with orthostatic symptoms.

No did not work but thanks anyway. SNT Gatchaman kindly helped me out.

Yes unfortunately, they do not report how many students had more than 40 bpm HR changes as that would give an indication of the current threshold. They only report the median (20) range (-15 + 61) and 2.5% (-1) and 97.5% (48) quartiles and mention that 23% had a HR increase of more than 30 bpms...

Thanks, it all seems to point to the same researcher: Phillip A. Low at the Mayo Clinic. Phillip A. Low, M.D. - Doctors and Medical Staff - Mayo Clinic

Same finding here: 9 of the 15 controls (60%) had an HR increase that was higher than 30 bpm after 10 minute passive tilt table testing. With a 10 minute standing test, 5 (33%) met the POT criterium. They proposed to increase the HR cutoff to 37 bpm which resulted in a sensitivity of 40% and a...

I suspect that study forms the justification for the > 40 bpm threshold for children, even though it showed that 5% of healthy controls had a HR increase higher than 42 bpm. The study not included healthy controls but also more than 600 children who were referred with diagnoses of orthostatic...

This abstract from a German study did 10 repeated tests and found that it did not lead to stable results. Intra- and interindividual reproducibility of heart rate variations in the tilt-table test - PubMed (nih.gov)

Thanks to @SNT Gatchaman for helping me out. In the study they had a control group of 20 men and 21 women aged 20 to 50 years. For the control group they report that "between the second and third minute of tilt, HR increased by 20.1 ± 8.9 bpm in men versus 14.8 ± 8.1 bpm in women." So it seems...

Thanks but I actually meant the 1993 Schondorf-Low paper where POTS was first defined: Idiopathic postural orthostatic tachycardia syndrome An attenuated form of acute pandysautonomia? Ronald Schondorf, PhD, MD, and Phillip A. Low, MDAUTHORS INFO & AFFILIATIONS January 1993 issue 43 (1_part_1)...

Thanks for the useful references @Nightsong Found some other ones too: Orthostatic heart rate does not predict symptomatic burden in pediatric patients with chronic orthostatic intolerance - PubMed (nih.gov) Orthostatic intolerance without postural tachycardia: how much dysautonomia? -...

Thanks. Does anyone have access to this paper? Haven't been able to find it online.

Where does the idea that >30bpm increase during tilt testing is pathologic came from? Does anyone know how this threshold was justified or where it was first used?

There were 252 participants in this study of which 123 in the age group of 18-29 (where POTS diagnosis is common). They only did 5 instead of 10 minute testing but don't think that would impact the conclusion (one would expect the HR increase to be even higher with 10 minute testing). Half of...

There are more of these. Plan to write a blog post about it to summarize the main findings. Might have important implications for POTS and OI research in ME/CFS.

Think I've more or less found what I was looking for: Normal versus abnormal: What normative data tells us about the utility of heart rate in postural tachycardia - PubMed (nih.gov) The authors did 5 minute tilt table testing in a sample of the general population and found that POT was quite...

Looks like a highly problematic article, suggesting the opposite of what actually should be done to help patients. It refers to the Cochrane review (Larun et al.) to argue that GET is beneficial and to the PACE trial to argue that pacing is not (they suggest the term should be abandoned)...

This is a historic paper from 1993 where POTS was first defined. I am very interested in reading what it says but do not have access to it. Anyone who can share a copy with me in PM?

Abstract To characterize the idiopathic postural orthostatic tachycardia syndrome (POTS), we reviewed the records of all patients aged 20 to 51 who presented to the Mayo Autonomic Reflex Laboratory and who exhibited tachycardia at rest or during head-up tilt. These patients were usually women...

Yes that is another big problem. But I meant something differently: a study that does tilt table testing in a representative sample of the general population to see how well POT correlates with OI and other symptoms.

The supplementary file gives the following data (my bolding): Head-up tilt table testing at 70 degrees from horizontal for up to 40 minutes was performed during which finger blood pressure (BP) was monitored continuously and upper arm blood pressure measured with a cuff every four minutes...