Abdurrahman Engin DEMİR, Menduh Savaş İLBASMIŞ, Nuran KÜÇÜK, Şükrü Hakan GÜNDÜZ, Cantürk TAŞÇI
Gulhane Medical Journal - 2026;68(2):118-126
Aims: Military jet pilots are mandated to undergo human centrifuge training (HCT) to experience the adverse effects of +Gz acceleration during flight. The present study aimed to analyze short-term respiratory changes following +Gz exposure via pulmonary function testing (PFT) among jet pilots. Methods: This single-center, cross-sectional study was conducted among healthy military jet pilots. Participants were classified as smokers or non-smokers. Each participant underwent PFTs immediately before and after the HCT. Forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), FEV1/FVC, maximal voluntary ventilation (MVV), peak expiratory flow rate (PEFR), and forced expiratory flow at 25-75% (FEF25-75%) have been measured. The participants' PFT parameters were evaluated to assess potential +Gz-related alterations. Results: The study included 21 male pilots with a mean age of 27.95+/-3.60 years. Ten (47.6%) pilots were active smokers. After HCT, significant improvements were observed in the mean values of FEV1 (4.45+/-0.55 vs. 4.55+/-0.57, p=0.001), FEV1/FVC (80.0+/-0.6 vs. 83.0+/-0.7, p=0.002), FEF25-75% (4.72+/-1.43 vs. 4.96+/-1.52, p=0.007), and MVV (169.3+/-28.6 vs. 181.5+/-32.4, p=0.002); however, no significant changes were observed in FVC or PEFR (p>0.05). Among smokers, significant post-training improvements were observed in FEV1, the FEV1/FVC ratio, and PEFR (p<0.05), whereas no significant changes were detected in FVC, FEF25-75%, or MVV (p>0.05). In non-smokers, significant increases were observed in FEV1, FEV1/FVC, and MVV (p<0.05), while the remaining parameters showed no significant changes. Conclusions: This study revealed that +Gz exposure was associated with short-term improvements in expiratory flow parameters and effort-dependent ventilatory performance in jet pilots. Additionally, subgroup analysis demonstrated that smokers predominantly exhibited significant increases in flow-dependent parameters.
