Relationship Between Exercise-induced Oxidative Stress Changes and Parasympathetic Activity in CFS

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Clin Ther. 2019 Jan 18. pii: S0149-2918(18)30611-8. doi: 10.1016/j.clinthera.2018.12.012. [Epub ahead of print]
Relationship Between Exercise-induced Oxidative Stress Changes and Parasympathetic Activity in Chronic Fatigue Syndrome: An Observational Study and in Patients and Healthy Subjects.
Polli A1, Van Oosterwijck J2, Nijs J3, Marusic U4, De Wandele I5, Paul L6, Meeus M7, Moorkens G8, Lambrecht L9, Ickmans K3.
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Abstract
PURPOSE:
Oxidative stress has been proposed as a contributor to pain in patients with myalgic encephalomyelitis/chronic fatigue syndrome(ME/CFS). During incremental exercise in patients with ME/CFS, oxidative stress enhances sooner and antioxidant response is delayed. We explored whether oxidative stress is associated with pain symptoms or pain changes following exercise, and the possible relationships between oxidative stress and parasympathetic vagal nerve activity in patients with ME/CFS versus healthy, inactive controls.

METHODS:
The present study reports secondary outcomes from a previous work. Data from 36 participants were studied (women with ME/CFS and healthy controls). Subjects performed a submaximal exercise test with continuous cardiorespiratory monitoring. Levels of thiobarbituric acid-reactive substances (TBARSs) were used as a measure of oxidative stress, and heart rate variability was used to assess vagal activity. Before and after the exercise, subjects were asked to rate their pain using a visual analogic scale.

FINDINGS:
Significant between-group differences in pain at both baseline and following exercise were found (both, P < 0.007). In healthy controls, pain was significantly improved following exercise (P = 0.002). No change in oxidative stress level after exercise was found. Significant correlation between TBARS levels and pain was found at baseline (r = 0.540; P = 0.021) and after exercise (r = 0.524; P = 0.024) in patients only. No significant correlation between TBARS and heart rate variability at baseline or following exercise was found in either group. However, a significant correlation was found between exercise-induced changes in HRV and TBARS in healthy controls (r = -0.720; P = 0.001).

IMPLICATIONS:
Oxidative stress showed an association with pain symptoms in people with ME/CFS, but no exercise-induced changes in oxidative stress were found. In addition, the change in parasympathetic activity following exercise partially accounted for the change in oxidative stress in healthy controls. More research is required to further explore this link.

Copyright © 2018. Published by Elsevier Inc.

KEYWORDS:
Autonomic nervous system; Chronic fatigue syndrome; Exercise; Oxidative stress; Pain

PMID:

30665828

DOI:

10.1016/j.clinthera.2018.12.012