Thursday, November 8, 2012

Loss of Capacity to recover from Acidosis on Repeat Exercise

http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2362.2011.02567.x/abstract

LOSS OF CAPACITY TO RECOVER FROM ACIDOSIS ON REPEAT EXERCISE IN
CHRONIC FATIGUE SYNDROME – A CASE CONTROL STUDY
David EJ Jones MD PhD1,†, Kieren G Hollingsworth PhD1,2,†, Djordje G
Jakovljevic PhD3,4,5, Gulnar Fattakhova MD3,4, Jessie Pairman3,4,
Andrew M Blamire PhD1,2, Michael I Trenell PhD1,4,5,‡, Julia L Newton
MD PhD3,4,‡
European Journal of Clinical Investigation © 2011 DOI:
10.1111/j.1365-2362.2011.02567.x

Author Information
1Institute of Cellular Medicine
2Newcastle Magnetic Resonance Centre
3Institute for Ageing and Health
4the UK NIHR Biomedical Research Centre in Ageing and Age Related Diseases
5Newcastle Centre for Brain Ageing and Vitality. Newcastle University, 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: j.l.newton@ncl.ac.uk

Abstract
Background:  Chronic fatigue syndrome (CFS) patients frequently
describe difficulties with repeat exercise. Here we explore muscle
bioenergetic function in response to 3 bouts of exercise.

Methods:  18 CFS (CDC 1994) patients and 12 sedentary controls
underwent assessment of maximal voluntary contraction (MVC), repeat
exercise with magnetic resonance spectroscopy and cardio-respiratory
fitness test to determine anaerobic threshold.

Results:  CFS patients undertaking MVC fell into 2 distinct groups. 8
(45%) showed normal PCr depletion in response to exercise at 35% of
MVC (PCr depletion >33%; lower 95% CI for controls). 10 CFS patients
had low PCr depletion (generating abnormally low MVC values). The CFS
whole group exhibited significantly reduced anaerobic threshold, heart
rate, VO2, VO2 peak and peak work compared to controls. Resting muscle
pH was similar in controls and both CFS patient groups. However, the
CFS group achieving normal PCr depletion values showed increased
intra-muscular acidosis compared to controls after similar work after
each of the 3 exercise periods with no apparent reduction in acidosis
with repeat exercise of the type reported in normal subjects. This CFS
group also exhibited significant prolongation (almost 4-fold) of the
time taken for pH to recover to baseline.

Conclusion:  When exercising to comparable levels to normal controls
CFS patients exhibit profound abnormality in bioenergetic function and
response to it. Although exercise intervention is the logical
treatment for patients showing acidosis any trial must exclude
subjects who do not initiate exercise as they will not benefit. This
potentially explains previous mixed results in CFS exercise trials.

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