Hormonal and inflammatory responses to high‐intensity functional training in male soldiers

This study investigated the effects of high‐intensity functional training (HIFT) on hormonal and inflammatory biomarker responses during military service. One hundred and twenty‐seven male conscripts were assessed over a 19‐week training period. The experimental group (EXP: n = 64) followed a structured HIFT program, while the control group (CON: n = 63) adhered to conventional military physical training. Blood samples were collected at baseline (PRE), week 10 (MID), and post‐intervention (POST) to measure serum testosterone, cortisol, testosterone/cortisol ratio, insulin‐like growth factor 1 (IGF‐1), sex hormone‐binding globulin (SHBG), high‐sensitivity C‐reactive protein (hs‐CRP), interleukin 6 (IL‐6), and tumor necrosis factor alpha (TNF‐α). Body composition and physical performance were also measured. Serum testosterone increased in both groups between PRE and POST (EXP: +3.3 ± 3.8 nmol·L −1 , p < 0.001; CON: +3.7 ± 3.4 nmol·L −1 , p < 0.001), while cortisol remained unchanged. Testosterone/cortisol ratio increased in both groups (+0.010 ± 0.010, p < 0.001 for both). IGF‐1 increased in CON (+4.4 ± 5.9 nmol·L −1 , p < 0.001) and SHBG increased in EXP (+3.1 ± 9.0 nmol·L −1 , p = 0.005). Inflammatory biomarkers (hs‐CRP, IL‐6) decreased in both groups. No adverse biomarker responses were observed, suggesting that HIFT was well tolerated during military service.