The Effects of a Single Bout of Resistance Activity at Two Intensities with Different Recovery Periods on IL-6, ACTH, and BDNF Levels in Female Bodybuilders

Introduction: Resistance exercise enhances physical performance and metabolic health, but responses vary based on intensity and recovery. This study investigated how different resistance training intensities and recovery periods affect interleukin-6 (IL-6), adrenocorticotropic hormone (ACTH), and brain-derived neurotrophic factor (BDNF) in female bodybuilders. Material & Methods: Twelve healthy female bodybuilders (25–35 years) completed two weekly sessions for four weeks: moderate intensity (75% 1RM) with 1- or 2-minute recovery (MLRT1/MLRT2) and high intensity (85% 1RM) with 1- or 2-minute recovery (HLRT1/HLRT2). Blood samples were taken 36 hours post-exercise after fasting. Serum IL-6, ACTH, and BDNF levels were analyzed via SPSS (v27; p < 0.05). Results: High-intensity training (85% 1RM) with 1-minute recovery significantly reduced IL-6 (p = 0.0001) and ACTH (p = 0.0001) while increasing BDNF (p = 0.0001) compared to lower intensities. Conclusion: HLRT with short recovery did not impair immunity and was linked to lower IL-6/ACTH and higher BDNF, suggesting anti-inflammatory and neurotrophic benefits in female bodybuilders.