Abstract

Objective: To investigate the effects of short-term prednisolone ingestion combined with intense training on exercise performance, hormonal (ACTH, PRL, LH, GH, TSH, DHEA, testosterone, insulin) and metabolic parameters (blood glucose, lactate, bicarbonate, pH). Methods: Eight recreational male athletes completed four cycling trials at 70-75% peak O2 consumption until exhaustion just before (1) and after (2) either oral placebo (Pla) or prednisolone (Cor, 60mg/day for 1 wk) treatment coupled to a standardized physical training (2 hours/day), according to a double-blind and randomized protocol. Blood samples were collected at rest, during exercise and passive recovery for the hormonal and metabolic determinations. Results: Time of cycling was not significantly changed after Pla but significantly increased (P<0.05) after Cor administration (Pla1: 50.4 ± 6.2; Pla2: 64.0 ± 9.1; Cor1: 56.1 ± 9.1; Cor2: 107.0 ± 20.7 min). There was no significant difference in any measured parameters after the week of training with Pla but a decrease in ACTH, DHEA, testosterone, PRL, GH and TSH was observed with Cor treatment during the experiment (P<0.05). No significant change in basal, exercise or recovery LH, insulin, lactate, pH or bicarbonate was found between the 2 treatments but blood glucose was significantly higher under Cor (P<0.05) at any moment. Conclusion: It is concluded that short-term glucocorticoid administration induced a marked improvement in endurance performance and further studies are needed to determine whether these results obtained in recreational male athletes maintaining a rigorous training schedule are gender dependent and applicable to elite athletes.