Researchers took continuous blood pressure measurements in people with ME/CFS and healthy controls while participants were at risk and then upon standing. They say heart-rate variability was significantly higher at rest in ME/CFS, and markers of parasympathetic nervous system activity were reduced.
Also, the blood pressure change upon standing was lower in ME/CFS than in controls. This finding is consistent with the theory that a symptom called orthostatic intolerance (dizziness upon standing) is linked to irregular blood-pressure changes.
Results also showed an imbalance between the sympathetic and parasympathetic nervous systems.
Importance as a Possible Biomarker
ME/CFS is currently hard to diagnose and has no universal and universally accepted biomarkers. The condition is considered both underdiagnosed and frequently misdiagnosed.
Blood-pressure monitoring is relatively simple and non-invasive. Medical facilities are all ready equipped to perform it and familiar with how it's done. That's a major advantage when it comes to a new diagnostic procedure.
However, don't expect this method to become standard overnight. A few doctors may experiment with it, but until we have more studies to validate this one, it won't be widely adopted.