Abnormalities in pH Handling by Peripheral Muscle and Potential Regulation by the Autonomic Nervous System in Chronic Fatigue Syndrome
David EJ Jones MD PhD 1 , Kieren G Hollingsworth MD PhD 2 , Roy Taylor MD 2 , Andrew M Blamire PhD 2 , Julia L Newton MD PhD 1,3
Institute of Cellular Medicine1 , Newcastle Magnetic Resonance Centre2
3 Institute for Ageing and Health, Newcastle University, UK
d.e.j.jones@ncl.ac.uk
Correspondence: Professor Julia L Newton
Institute for Ageing and Health
Medical School
Framlington Place
Newcastle-upon-Tyne
NE2 4HH
UK
Tel: 0191 2824128
Email:
julia.newton@nuth.nhs.uk
Chronic fatigue syndrome muscle bioenergetics autonomic dysfunction magnetic resonance spectroscopy
ABSTRACT
Objectives: To examine muscle acid handling following exercise in Chronic Fatigue Syndrome (CFS/ME) and the relationship with autonomic dysfunction.
Design: Observational study
Setting: Regional Fatigue Service.
Subjects & Interventions: CFS/ME (n=16) and age and sex matched normal controls (n=8) underwent phosphorus magnetic resonance spectroscopy (MRS) to evaluate pH handling during exercise. Subjects performed plantar flexion at fixed 35% load Maximum Voluntary Contraction. Heart rate variability was performed during 10 minutes supine rest using digital photophlethysmography as a measure of autonomic function.
Results: Compared to normal controls, the CFS/ME group had significant suppression of proton efflux both immediately post-exercise (CFS: 1.1 0.5 mM/min v Normal: 3.6 1.5 mM/min, p<0.001) and maximally (CFS: 2.7 3.4 mM/min v Control: 3.8 1.6 mM/min, p<0.05). Furthermore, the time taken to reach maximum proton efflux was significantly prolonged in patients (CFS: 25.6 36.1s v Normal: 3.8 5.2 s, p<0.05). In controls the rate of maximum proton efflux showed a strong inverse correlation with nadir muscle pH following exercise (r2=0.6; p<0.01). In CFS patients, in contrast, this significant normal relationship was lost (r2=0.003; p=ns). In normal individuals the maximum proton efflux following exercise were closely correlated with total heart rate variability (r2=0.7;p=0.007) this relationship was lost in CFS/ME patients (r2<0.001;p=ns).
Conclusion: Patients with CFS/ME have abnormalities in recovery of intramuscular pH following standardised exercise degree of which is related to autonomic dysfunction. This study identifies a novel biological abnormality in patients with CFS/ME which is potentially open to modification.
