title: Elucidating the unexplained underperformance syndrome in endurance athletes : the interleukin-6 hypothesis.
abstract: The unexplained underperformance syndrome (UPS), previously known as the overtraining syndrome (OTS), has been defined as a persistent decrement in athletic performance capacity despite 2 weeks of relative rest. It has been proposed that UPS may be caused by excessive cytokine release during and following exercise causing a chronic inflammatory state and 'cytokine sickness'. This article extends that hypothesis by proposing that time-dependent sensitisation could provide a model through which the aetiology of UPS may be explained. In this model, the principal abnormal factors in UPS are an increased production of and/or intolerance to interleukin (IL)-6 during exercise. Strategies to attenuate the IL-6 response to exercise that may also reduce an athlete's susceptibility to UPS are proposed.
authors.affiliation: UCT/MRC Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, Sports Science Institute of South Africa, University of Cape Town, Newlands, South Africa. paularobson@emailacc.com
authors.forename: Paula
authors.initials: P
authors.lastname: Robson
mesh_terms: D005221:Fatigue / Q000097:blood* / Q000209:etiology / Q000235:genetics / Q000523:psychology; D006801:Humans; D015850:Interleukin-6 / Q000097:blood* / Q000235:genetics / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology; D013177:Sports / Q000502:physiology / Q000523:psychology; D013315:Stress, Psychological / Q000097:blood / Q000150:complications; D013577:Syndrome
chemical_list: D015850:Interleukin-6