@dr.zac.spiritos: Can you have orthostatic intolerance even if your POTS testing is normal? Absolutely. Orthostatic intolerance means you feel unwell when upright, and it can happen even when your heart rate and blood pressure are completely normal during a NASA Lean Test or tilt table test. Why? Because POTS is only one potential cause. One possibility is endothelial dysfunction, involving the cells that line our blood vessels and help regulate blood flow. This has been implicated in ME/CFS. Interestingly, a medication called pyridostigmine, also known as Mestinon, has shown promising results in people with ME/CFS, including improvements in orthostatic intolerance and handgrip strength in a small study. This doesn’t work for everyone nor is it a full proof option, but it can help in circumstances like these. Another possibility is pelvic venous congestion, where abnormal venous drainage and blood pooling may contribute to symptoms that worsen when standing. The point is that orthostatic intolerance can have multiple underlying mechanisms, and not all of them show up on conventional autonomic testing. A negative POTS test doesn’t mean there’s no physiological reason you feel terrible standing up. Sometimes we need to look beyond POTS to understand why. For educational purposes only. Not medical advice. #dysautonomia #pots #heds #hypermobility #mcas

Dr. Zac Spiritos

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Saturday 14 November 2026 05:53:34 GMT