Synergistic Effects of Combined Pilates and High-Intensity Interval Training on Neuroendocrine, Metabolic, and Performance Outcomes in Recreational Sports Players

Background Overtraining syndrome (OTS) is characterized by hypothalamic–pituitary–adrenal (HPA) axis dysregulation and chronic cortisol elevation, affecting up to 35–60% of competitive athletes [3,4]. While high-intensity interval training (HIIT) enhances cardiorespiratory fitness [10,12], and Pilates improves neuromuscular control and stress modulation [16–18], integrated interventions targeting neuroendocrine-metabolic optimization remain underexplored. Trial registration The study was retrospectively registered with the ISRCTN Registry on 31 July 2026 under registration number ISRCTN10727055. Objective To investigate the effects of a 16-week combined Pilates and HIIT program on serum cortisol, cardiorespiratory fitness, muscular endurance, metabolic markers, and perceived stress in competitive athletes. Methods Eighty competitive athletes (mean age 25.39 ± 0.69 years) participated in a prospective controlled interventional study conducted in Chennai, India, between January and May 2024. Results Post-intervention analysis showed significant reductions in cortisol (−34.3%, p < 0.001) and improvements in VO₂max (+11.8%, p = 0.001), push-ups (+25.3%, p < 0.001), and crunches (+119%, p < 0.001). Fasting glucose decreased (−5.2%, p = 0.004), and HDL cholesterol increased (+8.3%, p < 0.001). Cortisol demonstrated a strong inverse correlation with PSS scores (r = −0.68, p < 0.001). Conclusions Combined Pilates-HIIT training significantly improved neuroendocrine regulation, fitness performance, and selected metabolic parameters. These findings support integrated training approaches for performance optimization and stress regulation in competitive athletes.