Somebody on Twitter believes it could be related to Ischemia-Reperfusion (muscle oxygen deprivation).
ME/CFS pathway is related to neurovascular anomalies and ischemia/reperfusion injury.
Another neurovascular issue related to this pathologic process is Raynaud Phenomenon.
Systemic Sclerosis is another pathology related to chronic ischemia/reperfusion injury.
Systemic Sclerosis is a tissu fibrosis coming downstream the I/R process in people who have the genetic that favor fibrosis response.
Raynaud Phenomenon often come some years before the Sclerosis shows up.
I'm convinced that ME/CFS are at higher risk for Raynaud and Sclerosis...