Abnormalities in pH handling by peripheral muscle and potential regulation by the autonomic nervous system in chronic fatigue syndrome

. Jones DEJ, Hollingsworth KG, Taylor R, Blamire AM, Newton JL (From the Institute of Cellular Medicine, Newcastle Magnetic Resonance Centre, and Institute for Ageing and Health, Newcastle University, UK). Abnormalities in pH handling by peripheral muscle and potential regulation by the autonomic nervous system in chronic fatigue syndrome. J Intern Med 2010; 267: 394–401. 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. Chronic fatigue syndrome (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 min 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 postexercise (CFS: 1.1 ± 0.5 mmol L−1 min−1 vs. normal: 3.6 ± 1.5 mmol L−1 min−1, P