An elite ultra-endurance athlete, who had previously undergone
physiological and performance testing, developed chronic
fatigue syndrome (CFS). An incremental cycling exercise test
conducted while he was suffering from CFS indicated decreases
in maximum workload achieved (Wmax; -11.3%), the maximum
oxygen uptake (VO2max; -12.5%), and the anaerobic threshold
(AT; -14.3%) compared to pre-CFS data. A third test conducted
after the athlete had shown indications of significant
improvement in his clinical condition revealed further
decreases in Wmax (-7.9%), VO2max (-10.2%) and AT (-8.3%).
These data, along with submaximal exercise data and muscle
biopsy electron microscopic analyses, suggest that the
performance decrements were the result of detraining, rather
than an impairment of aerobic metabolism due to CFS per se.
These data may be indicative of central, possibly
neurological, factors influencing fatigue perception in CFS