Abstract

Objective: To examine whether acute glucocorticoid (GC) intake alters performance and selected hormonal and metabolic variables during submaximal exercise.

Methods: Fourteen recreational male athletes completed two cycling trials at 70-75% maximum O₂ uptake starting 3h after an ingestion of either a placebo (PLA) of lactose or oral GC (20 mg of prednisolone) and continuing until exhaustion, according to a double-blind randomized protocol. Blood samples were collected at rest, after 10, 20, 30 min and at exhaustion for growth hormone (GH), adrenocorticotropic hormone (ACTH), DHEA, prolactin (PRL), insulin (INS), blood glucose (GLU), lactate (LAC) and interleukin-6 (IL-6) determination.

Results: Time of cycling was not significantly changed after GC or PLA administration (GC: 55.9 ± 5.2 vs PLA: 48.8 ± 2.9 min). A decrease in ACTH and in DHEA (P<0.01) was observed with GC during all of the experiment and in IL-6 since exhaustion (P<0.05). No change in basal, exercise or recovery GH, PRL and INS was found between the 2 treatments but blood glucose was significantly more elevated under GC (P<0.05) at any moment.

Conclusion: From these data, acute systemic GC administration did appear to alter some metabolic markers but did not influence performance during submaximal exercise.