Affiliations: Université MONTPELLIER1, UFR de Médecine, Laboratoire de Physiologie des Interactions, Montpellier Institut de Biologie, Boulevard Henri IV, F-34062 France; Service Central de Physiologie Clinique, Centre d'Exploration et de Réadaptation des Anomalies du Métabolisme Musculaire (CERAMM), CHU Lapeyronie 34295 Montpellier-cédex 5, France
Abstract: There is a lack of consensus about the biological diagnosis of the overtraining syndrome (OTS). Recently, efforts have been made to standardize its clinical diagnosis (e.g., standardized questionnaires like that of the French consensus group on overtraining of the Société Française de Médecine du Sport–SFMS). We previously reported that the early signs of overtraining (= “overreaching”) in elite sportsmen are associated with a hemorheologic pattern (raised hematocrit and plasma viscosity ηp) that suggests some degree of reversal of the “autohemodilution” which characterizes fitness, and that the feeling of heavy legs in overtrained athletes is related to higher ηp and higher red cell aggregation. We thus investigated on a sample of 48 athletes (age 24±1 yr), referred for possible diagnosis of overtraining to what extent plasma viscosity is a predictor of OTS. From those 48 athletes 10 had a value of ηp in the highest quartile (ηp>1.44 pPa.s) and 8 of them had a diagnosis of overreaching, while in the 38 whose ηp was <1.44 mPa.s there were 20 cases of overreachings. Overt cases of OTS were found in 1 subject of the highest quintile and two in the lowest. Thus the predictive value of ηp for early stages (overreaching) or chronicized stages (overtraining syndrome) is as follows: (a) prediction of overreaching: sensitivity 28.57%; specificity 90%; positive predictive value 80%; negative predictive value 47.37%; (b) prediction of chronicized overtraining: sensitivity 2.70%; specificity 18.18%; positive predictive value; 10.00%; negative predictive value 5.26%. These results show that ηp is a rather specific, although poorly sensitive predictor of overreaching but has no interest in the diagnosis of the overtraining syndrome itself.
