Dr. Newton’s studies suggest the muscles of people with ME/CFS are not efficiently removing the acids that build up during exercise. It’s possible this acid buildup is contributing to the hyperventilation, and, of course, the exercise problems in ME/CFS. Earlier she mentioned she was determining if drugs could reverse that acid buildup.
In terms of how problems with vascular control and autonomic dysfunction could lead to problems with cognition: it is well recognized in the field of autonomic dysfunction that the lower your blood pressure is, the worse you perform on memory tests, and that if your blood pressure falls when you stand up, then the degree of that fall associates with cognitive decline over time.
We have suggested from our MRI studies that the high levels of acid that accumulate in the muscles of patients with ME/CFS could be because they are having difficulty removing acid via specific transporters, or because there is lack of runoff of acid from the muscles, as they exercise, into the vascular system.
So it may be that there is a specific membrane abnormality of these specific transporters, or alternatively it could be entirely related to the caliber of the blood vessels.
To me chronotropic incompetence is simply an inability of the heart to function properly in response to stressors such as standing. That would be completely in keeping with findings of tachycardia in response to the stress of standing, i.e., there is an inappropriate response to the stress of standing by the autonomic nervous system.