Chronic fatigue syndrome. A brief review of functional disturbances and potential therapy.

The chronic fatigue syndrome (CFS) is debilitating for both athletes and the general population. A review of etiology and mechanisms underlying functional disturbances is undertaken to provide a valid basis for therapeutic options. The review focuses on CFS as characterized by standard diagnostic criteria, building on previous reviews through use of articles identified by Medline search. Overtraining, a negative energy balance, excessive physical or environmental stress, disorders of personality and affect, dysfunction of the hypophyseal-pituitary adrenal axis, hormonal imbalance, nutritional deficits, immune suppression or activation and chronic infection have all been proposed as factors precipitating CFS, but none of these precipitants are observed consistently. Impairments of peak aerobic power and muscle strength, together with many functional disturbances, seem related to patient- or physician-imposed inactivity. Once CFS is established, treatment should aim at breaking the vicious cycle of effort avoidance, deterioration in physical condition and increasing fatigue through a combination of psychotherapy, general encouragement and a progressive exercise regimen.