Effet de l'entraînement sur la désaturation de l'oxyhémoglobine au cours d'une saison sportive chez le triathlète

Introduction – Endurance athletes frequently present an exercise induced hypoxemia at sub-maximal or maximal exercise.Methods – The results of a recent study that compared two groups of highly trained athletes, one with exercise induced hypoxemia and the other without, suggested that a difference in training volume (4 hours per week) and/or training intensity may explain the difference in the exercise-induced hypoxemia observed. The aim of the study was to evaluate the effects of volume and/or intensity of training on exercise induced desaturation in triathletes during a competitive season.Conclusions – This study showed that exercise induced desaturation was related to both volume and intensity of training in triathletes.     

Effet de l'intensité de l'entraînement sur les réponses en catécholamines à l'exercice supramaximal chez des endurants de sexe masculin

Introduction – In this study we compared catecholamine responses to the Wingate-test in 2 male endurance trained groups: 6 middle distance runners (DFC) (800m and 1500m) and 6 long distance runners (DFL) (5000 m and 10,000 m).Results – As expected DFL exibited higher maximal oxygen consumption (72 ± 2,5 vs 79 ± 4,5 ml min^–1kg ^–1 fat free mass respectively for DFC and DFL) and DFC exibited higher performances during the Wingate-test (15,8 ± 0,3 vs 14,7 ± 0,4 W kg^–1 fat free mass respectively for DFC and DFL). In opposite differences between maximal catecholamine responses (Adrénaline: 3,8 ± 0,7 vs 3,5 ± 0,3 nmol l^–1. Noradrénaline: 20,4 ± 1,5 vs 16 ± 2,1 nmol l^–1 respectively for DFC and DFL) and maximal plasma lactate were not significant.Conclusion – This results suggests that endurance specificity may not induce different catecholamines responses to sprint exercise.     

Dissociation de la réponse du système adrénergique à l'exercice après un repas hyperglucidique et ses conséquences sur la mobilisation des lipides

Aims – Evaluate hyperglucidic meal effect on changes of catecholamines concentrations and on lipids mobilization during exercise.Methods and results – During exercise (one hour at 50% of VO_2max), the adrenaline concentrations increased twice more in fed men than in fast men, whereas no difference was shown for noradrenaline. The exercise-induced increase in lipolysis was similar whatever the nutritional state of subjects (fed or fasted).Conclusion – In fed men, important increase of adrenaline concentrations during exercise counteracted antilipolytic effect of insulin wich occured after ingestion of hyperglucidic meal.