Eur J Appl Physiol 2015 Jun 30;115(6):1359-66. Epub 2015 Jan 30.
Department of Kinesiology, California State University, 800 N. State College Blvd., Fullerton, CA, 92834, USA,
Purpose: Resistance exercise induces a host of endocrine responses that potentiate its effects on body composition and metabolism. Excess adiposity negatively affects some hormonal responses to exercise in sedentary men. This study compared the resistance exercise (RE)-associated growth hormone (GH), insulin-like growth factor-1 (IGF-1), and testosterone responses in lean vs. obese physically active men.
Methods: Ten healthy physically active obese males (body fat % 36.2 ± 4.03, age 24.6 ± 3.7 years, mass 104.5 ± 15.5 kg, height 178.8 ± 6.0 cm) were compared to ten lean counterparts (body fat % 12.7 ± 2.9, age 24.6 ± 3.7 years, mass 77.1 ± 6.4 kg, height 177.2 ± 4.8 cm). The muscular endurance RE protocol consisted of six sets of ten repetitions per leg of stepping onto an elevated platform (20 % of participant's height) while wearing a weighted-vest (50 % of participant's lean mass). Pre-, immediately post-exercise (IP), and three more blood samples were collected during the one-hour recovery.
Results: When accounting for baseline differences there were no group by time interactions for GH (p = 0.33); or LH (p = 0.52). Lean presented a trend towards significance for higher IGF-1 IP (p = 0.08) than obese. Testosterone IP was similar in obese and lean, but lower in obese than lean at 30 min into recovery (p < 0.01). AUC were lower in obese than lean for all hormones (p < 0.05 for all).
Conclusion: These findings suggest that excess adiposity does not appear to negatively affect the immediate GH and T responses to RE in active males; but possibly negatively affects IGF-1. However, the baseline and integrated concentrations during recovery appear negatively affected by excess adiposity.