Autonomic markers, chronic fatigue syndrome, and post-exertion states, by Fred Friedberg in Journal of Psychosomatic Research Vol 127, Dec 2019, [https://doi.org/10.1016/j.jpsychores.2019.109845]
Article extracts:
A large body of evidence suggests that autonomic imbalance, i.e., hyperactive sympathetic nervous system and hypoactive parasympathetic nervous system, is associated with a number of pathological conditions and diseases, and may be a final common pathway to increased morbidity and mortality [1].
Heart rate variability (HRV), a measure of inter-beat interval fluctuations and more broadly of parasympathetic (vagal) activity has been successfully used to index autonomic imbalances.
…In conclusion, reduced HRV may be a sensitive (and conveniently assessed) autonomic indicator of post-exertional worsening and a correlate of activity and fatigue that may differentiate CFS from healthy controls. If negative changes in HRV are uniquely associated with greater PEM and day-to-day illness fluctuations in CFS, then its potential as an illness marker can be productively tested in exertional challenge designs that amplify PEM-related symptom exacerbations.
