Article

Reduced functional capacity and postexertion fatigue after physical
activity are hallmark symptoms of chronic fatigue syndrome (CFS) and may even
qualify for biomarker status. That these symptoms are often delayed may explain
the equivocal results for clinical cardiopulmonary exercise testing in people
with CFS. Test reproducibility in people who are healthy is well documented. Test
reproducibility may not be achievable in people with CFS because of delayed
symptoms. The objective of this study was to determine the
discriminative validity of objective measurements obtained during cardiopulmonary
exercise testing to distinguish participants with CFS from participants who did
not have a disability but were sedentary. DESIGN: A prospective cohort study was
conducted. METHODS: Gas exchange data, workloads, and related physiological
parameters were compared in 51 participants with CFS and 10 control participants,
all women, for 2 maximal exercise tests separated by 24 hours. RESULTS:
Multivariate analysis showed no significant differences between control
participants and participants with CFS for test 1. However, for test 2,
participants with CFS achieved significantly lower values for oxygen consumption
and workload at peak exercise and at the ventilatory or anaerobic threshold.
Follow-up classification analysis differentiated between groups with an overall
accuracy of 95.1%. LIMITATIONS: Only individuals with CFS who were able to
undergo exercise testing were included in this study. Individuals who were unable
to meet the criteria for maximal effort during both tests, were unable to
complete the 2-day protocol, or displayed overt cardiovascular abnormalities were
excluded from the analysis. CONCLUSIONS: The lack of any significant differences
between groups for the first exercise test would appear to support a
deconditioning hypothesis for CFS symptoms. However, the results from the second
test indicated the presence of CFS-related postexertion fatigue. It might be
concluded that a single exercise test is insufficient to reliably demonstrate
functional impairment in people with CFS. A second test might be necessary to
document the atypical recovery response and protracted fatigue possibly unique to
CFS, which can severely limit productivity in the home and workplace.

Langue : ANGLAIS