It’s Not Just Fatigue — ME/CFS Study Highlights Autonomic Breakdown
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A major U.S. research project just delivered one of the clearest pictures yet of how the autonomic nervous system is affected in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). The study, known as the Multi-Site Clinical Assessment of ME/CFS (MCAM), examined patients from seven specialty clinics over the course of eight years and found overwhelming evidence that autonomic dysfunction is not just a side effect of ME/CFS—it’s at the core of it.
The MCAM study collected data from over 440 people—301 with ME/CFS and 141 healthy controls—and used validated tools like the COMPASS‑31 symptom questionnaire and a modified NASA lean test to assess autonomic symptoms such as dizziness, lightheadedness, cold extremities, digestive issues, and problems with visual focus or light sensitivity.
What they found was staggering: 97% of ME/CFS participants had at least one symptom of autonomic dysfunction. Compare that to just 29% of healthy controls. People with ME/CFS also scored five times higher on average on the COMPASS‑31, a scale that measures symptom severity across domains like cardiovascular regulation, gastrointestinal function, thermoregulation, and bladder control.
And the more severe the autonomic symptoms, the more severe the ME/CFS. Researchers saw a clear link between illness severity and symptoms like orthostatic intolerance (trouble remaining upright), GI distress, and visual regulation issues. In other words, these aren’t peripheral problems. They’re closely tied to how sick someone actually feels.
This is powerful validation for people living with ME/CFS. For decades, patients have reported being brushed off when describing things like feeling faint when standing, struggling with digestion, or being overly sensitive to temperature or light. The MCAM study offers hard data showing these are real, measurable symptoms—and that they affect nearly everyone with the condition.
Most importantly, the researchers emphasized the need to screen for and treat autonomic dysfunction as part of managing ME/CFS. This could include tools like tilt or lean testing, symptom questionnaires, and individualized treatment plans that address dysautonomia directly. While there’s still no cure, understanding what’s actually happening in the body is a crucial step toward better care and quality of life.
