title: Effects of meal form and composition on plasma testosterone, cortisol, and insulin following resistance exercise.
abstract: The purpose of this study was to examine the effects of postexercise feeding on plasma levels of insulin, testosterone, cortisol, and testosterone:cortisol (T:C). Ten experienced, resistance trained males (20.7 +/- 0.95 years) were given whole food (WF: protein 38 g; carbohydrate 70 g; fat 7 g), a supplemental drink (SD; isocaloric and isonitrogenous to WF), an isocaloric carbohydrate beverage (C), or a placebo beverage (P) immediately, 2 and 4 hours after a standardized weight training protocol on 4 days, each separated by 1 week, in a repeated measures design. Subjects also received a standardized meal at 7 and 12 hours postexercise. Insulin, testosterone, and cortisol were measured pre-exercise and during 24 hours of recovery (at 0.5, 2.5, 4.5, 8, and 24 hours) using venous blood samples. Significant (condition 3 time) interactions were found for insulin, testosterone, and T:C, but not for cortisol (p <. 05). The SD yielded a greater response for insulin than all other conditions. Conversely, P demonstrated the greatest values for testosterone and T:C at 2.5 and 4.5 hours postexercise. Cortisol did not vary between conditions and there were no condition effects for insulin, testosterone, cortisol, and T:C at 8 or 24 hours. In conclusion, the efficacy of postexercise feeding for optimizing T:C and muscle growth is unclear; however, consumption of SD appears to maximize circulating insulin for several hours following resistance exercise.
authors: Department of Exercise and Sport Sciences, Ithaca College, Ithaca, NY 14850, USA.
authors: R J
authors: RJ
authors: Bloomer
authors: G A
authors: GA
authors: Sforzo
authors: B A
authors: BA
authors: Keller
mesh_terms: D000328:Adult; D004032:Diet; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004041:Dietary Fats / Q000008:administration & dosage; D004044:Dietary Proteins / Q000008:administration & dosage; D019587:Dietary Supplements; D004311:Double-Blind Method; D004734:Energy Metabolism; D015444:Exercise / Q000502:physiology*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D007328:Insulin / Q000097:blood*; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism / Q000502:physiology; D013739:Testosterone / Q000097:blood*; D013997:Time Factors; D014891:Weight Lifting
chemical_list: D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004044:Dietary Proteins; D007328:Insulin; D013739:Testosterone; D006854:Hydrocortisone