Recent Research on Orthostatic Intolerance (OI) in ME/CFS, Long-COVID & EDS

My browser has about 40 open tabs right now (!), and many of them are recent news or research on ME/CFS, long-COVID, and related conditions that I want to share with you. If only there were more hours in a day (or I didn't have to waste two of them napping every day)! So, here, I've compiled some fascinating recent (in the past few years) research into Orthostatic Intolerance in these conditions.

Orthostatic Intolerance or OI is an integral part of ME/CFS--over 97% of ME/CFS patients have some form of OI (and many of those with long-COVID, EDS, fibro, MS, and Lyme, too). So, if you have ME/CFS, then you do have OI, too, though you may not be aware of it. OI is an umbrella term encompassing several conditions where the body cannot maintain a steady blood pressure and/or heart rate when upright (standing or even sitting up). The two most common types of OI in ME/CFS are NMH, where the BP drops when you are upright, and POTS, where the HR goes up when you are upright. Rarer forms of OI--like where the BP rises when upright or BP and HR jump all over the place--also exist. The good news is that OI is fairly easy to treat & often brings dramatic improvement! It's what got my two sons back to school full-time when they were young and what allows my son and I to live fairly active lives now (he starts a full-time job next month!).

This detailed blog post about OI includes more information on OI, including all the basics of diagnosis and treatment, plus our own successful experiences treating it. In addition, I wrote a 2-part article for the ProHealth website on OI that is perfect for sharing with doctors because it is short and to the point and includes scientific references at the end, in case your doctor wants to look into it further. Part 1 is Diagnosing OI in ME/CFS and Part 2 is Treating OI in ME/CFS (both are relevant to all conditions mentioned above that include OI). 

 

With that basic information in mind, here are some fascinating studies that bring further light to the severe impact that OI can have on us patients. Many of these studies deal with finding impaired blood flow to the brain, causing severe symptoms, during even mild orthostatic (upright) challenges in ME/CFS patients. Note that any research on OI in ME/CFS will generally also be applicable to those with long-COVID, Ehlers-Danlos Syndrome (EDS), and often fibro and Lyme also.

• An interview with Dr. Peter Rowe, MD, Johns Hopkins (renowned OI in ME/CFS expert) about OI, brain blood flow, and venous congestion in ME/CFS. In this video, he discusses some of the studies listed below.
• From 3 months ago, a video presentation from Dr. Rowe on Updates on Orthostatic Intolerance in EDS. 
• Study (2023): Worsening Symptoms is Associated with Larger Cerebral Blood Flow Abnormalities During Tilt Table Testing in ME/CFS. This clearly shows that OI = less blood flow to the brain = worse symptoms, showing what a serious impact OI has on ME/CFS patients.
• Study (2020): Cerebral Blood Flow is Reduced in Severe ME/CFS Patients During Mild Orthostatic Stress Testing. Typical tilt table testing involves starting from a horizontal position and continuing until the patient is at a 70% standing position for at least 30 minutes. Many more severe patients can't tolerate that kind of test, and even moderate patients will crash badly after it. This study clearly showed that in a group of severe ME/CFS patients, a short test of only 20 minutes, going up to only a 20% position (the equivalent of sitting up in bed), provoked the same reduction in blood flow to the brain.
• Study (2020). Reductions in Cerebral Blood Flow Can Be Provoked by Sitting in Severe ME/CFS Patients. In a study of 100 severe ME/CFS patients (37 of whom also had fibro), there was a 24.5% reduction in cerebral blood flow just from sitting for an hour, even when heart rate and blood pressure didn't show significant changes. This shows that merely sitting can provoke a severe reaction and symptoms and that OI could potentially be diagnosed from a sitting test in severe patients who can't tolerate a standing test or full tilt table test. It also shows that severe effects are caused from being upright (OI), even if BP and HR don't show it.
  
• Paper in Science (2021). Cerebral Blood Flow Remains Reduced After Tilt Table Testing in ME/CFS Patients. This showed that the effects of being upright remain even after the patient is sitting or lying down--something that every patient who crashes after having to stand for a period of time knows all too well!

I find all of these studies absolutely fascinating because:

• OI can be difficult to diagnose, as I described in Challenges in Diagnosing OI, so measuring cerebral blood flow (blood flow to the brain) provides an alternative testing method that may be more accurate.
• These tests--showing reduced blood flow to the brain--show very clearly the severe impact that OI (and being upright) can have on ME/CFS patients, in obvious, quantifiable terms that doctors can understand.
• These studies show how even minimal orthostatic stress--sitting or even lying down at a 20-degree upright angle--can provoke severe symptoms that linger. This is something patients know instinctively, but it's nice to have proof to show doctors!

Again, the good news is that Orthostatic Intolerance is very treatable, and treating OI effectively can provide significant improvement in all symptoms! Finding exactly the right combination of OI treatments for each person can be tricky. It requires patience and persistence! For instance, there are almost 40 different beta blockers alone, plus many other treatment options, and they all work differently for each person. But it is well worth the effort to keep trying until you find what works for you, as my son and I have.

Have you tried treatments for OI yet? What has worked for you?

Please leave a comment below.

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