El otro día hablábamos de marcadores para el SFC. Bien, aquí hay otro nuevo. Se demuestra que tras la disminución del pH en el SFC en los músculos tras ejercicio, el flujo de protones que ha de servir para aumentar el pH y recuperar el músculo es más lento que en los controles sanos.
J Intern Med. 2010 Apr;267(4):394-401.
Abnormalities in pH handling by peripheral muscle and potential regulation
by the autonomic nervous system in chronic fatigue syndrome.**
Jones DE, Hollingsworth KG, Taylor R, Blamire AM, Newton JL.
Institute of Cellular Medicine, Newcastle University, Newcastle-upon-Tyne,
UK.
*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: 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 < 0.001)
and maximally (CFS: 2.7 +/- 3.4 mmol L(-1) min(-1) vs. control: 3.8 +/- 1.6
mmol L(-1) min(-1), P < 0.05). Furthermore, the time taken to reach maximum
proton efflux was significantly prolonged in patients (CFS: 25.6 +/- 36.1 s
vs. 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 (r(2) = 0.6; P < 0.01). In CFS patients, in contrast, this
significant normal relationship was lost (r(2) = 0.003; P = ns). In normal
individuals, the maximum proton efflux following exercise were closely
correlated with total heart rate variability (r(2) = 0.7; P = 0.007) this
relationship was lost in CFS/ME patients (r(2) < 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.