Background. Chronic fatigue syndrome (CFS) patients often complain that physical exertion
produces an increase of complaints, leading to a greater need for rest and more time spent in bed.
It has been suggested that this is due to a bad physical fitness and that physical deconditioning is
a perpetuating factor in CFS. Until now, studies on physical deconditioning in CFS have shown
inconsistent results.Methods. Twenty CFS patients and 20 matched neighbourhood controls performed a maximal
exercise test with incremental load. Heart rate, blood pressure, respiratory tidal volume, O2
saturation, O2 consumption, CO2 production, and blood-gas values of arterialized capillary blood
were measured. Physical fitness was quantified as the difference between the actual and predicted
ratios of maximal workload versus increase of heart rate. Fatigue, impairment and physical activity
were assessed to study its relationship with physical fitness.Results. There were no statistically significant differences in physical fitness between CFS patients
and their controls. Nine CFS patients had a better fitness than their control. A negative relationship
between physical fitness and fatigue was found in both groups. For CFS patients a negative
correlation between fitness and impairment and a positive correlation between fitness and physical
activity was found as well. Finally, it was found that more CFS patients than controls did not
achieve a physiological limitation at maximal exercise.Conclusions. Physical deconditioning does not seem a perpetuating factor in CFS.
The role of herpesviruses 6 and 7 in the development of chronic fatigue syndrome: a review of literature and description of clinical cases
