Exercise training in PoTS – 20 years after our randomised trial

2005: a randomised trial in young soldiers

At the Medical University of Vienna we screened 2,768 military recruits for orthostatic intolerance with a questionnaire and tilt-table testing and found 36 cases. Thirty-one of them entered a randomised controlled trial: three months of jogging versus no training. At the end, only 6 of 16 trained participants still met the criteria for orthostatic intolerance, compared with 10 of 11 in the control group (p = 0.008), and their symptom score fell from 1.79 to 1.04 while the controls did not change. Our conclusion was that endurance training should be considered part of the treatment of orthostatic intolerance. Two honest caveats: the participants were young men, and “orthostatic intolerance” in 2005 was a broader label than PoTS by today’s criteria.

2010–2016: the “small heart” and the Texas training programme

Benjamin Levine’s group in Dallas then explained why training works. Patients with PoTS had a smaller left ventricular mass (median 1.26 vs. 1.45 g/kg) and a lower blood volume (60 vs. 71 ml/kg) than healthy controls – a picture resembling deconditioning. In a head-to-head trial, three months of training improved symptoms, haemodynamics and quality of life, whereas the beta-blocker propranolol did not. Short-term training raised stroke volume and lowered the heart rate at any given workload. The key practical idea from these studies: start horizontally – rowing, swimming, recumbent cycling – so that patients can train without the upright posture that provokes their symptoms, and move to upright exercise only as fitness improves.

When the same programme was rolled out through an international registry in a community setting, 103 of 251 enrolled patients completed it – and 71 % of those who completed no longer met the PoTS criteria. The heart-rate rise on standing fell from 46 to 23 beats per minute, and in the 31 patients followed for 6–12 months the effect persisted. The drop-out rate is part of the result: more than half did not finish.

Guidelines and the state of the evidence

The 2015 Heart Rhythm Society consensus and the 2019 NIH expert meeting put exercise training, together with fluids, salt and compression, at the start of treatment, before any medication – and both noted that no drug is approved for PoTS and that the evidence for most drugs is thin. A 2018 meta-analysis in Mayo Clinic Proceedings found only three small randomised trials among 28 studies and rated each treatment class as “moderately effective” at best. A 2025 systematic review of randomised trials counted 21 trials with 750 patients in total over 23 years. The most recent review in JAMA (2026) still lists structured, supervised aerobic training as first-line therapy. In short: the direction of the evidence has not changed since 2005, but it is built on small studies, and the 2025 Frontiers review rightly points out that we know more about heart rates than about symptom burden and daily function.

What has changed: the dose is individual

The second decade of research is about how to train. A 2023 randomised trial compared a semi-supervised programme with personalised intensity and progression against standard advice: peak oxygen uptake rose by 3.4 ml/kg/min in the training group and did not change with standard care, exercise tolerance improved, and 80 % of trained patients had a delayed onset of symptoms during exercise. Remote and home-based programmes have been shown to be feasible and acceptable (the UK PULSE trial, 2025; a Swedish 200-patient trial is under way), and clinicians who treat severely affected, house- or bed-bound patients argue for individualised, remotely supervised programmes rather than fixed protocols. The message is not “exercise more” but “exercise at the right dose, with progression guided by symptoms”.

How I approach it today

1. Confirm the diagnosis and exclude mimics – active stand or tilt test, ECG, blood tests, echocardiogram where indicated; thyroid, adrenal, anaemia, medication effects.
2. Screen for PEM before any exercise advice. Two questions and, if in doubt, a symptom diary over two weeks decide which path we take.
3. PoTS without PEM: fluids and salt, compression, then a stepwise programme starting horizontally (recumbent bike, rowing, swimming) three to five times a week, progressing to upright exercise over months; strength training for the legs; heart-rate guided intensity; medication (e.g. beta-blocker, ivabradine, midodrine) only where symptoms demand it.
4. PoTS with PEM / ME/CFS: pacing first – staying below the individual exertion threshold, planned rest, heart-rate monitoring; gentle recumbent activity only as tolerated and with supervision; never “push through”.
5. Review: standing test, symptom score and activity level after 8–12 weeks; adjust the dose, not the goal.