Effects of Gravitational Acceleration on Physical Fitness, Stress, and Immunity Levels of Prospective Air Force...

In this study, we aimed to measure the change in salivary cortisol and immunoglobulin A (IgA) levels of Air Force cadets before and after undergoing a G-test; further, we aimed to assess the changes in stress, fatigue, and immunity level of cadets after experiencing gravitational acceleration. Thirty-five senior male cadets from the Republic of Korea Air Force were enroled (age, 20.27 ± 0.53 years; height, 174.11 ± 3.06 cm; weight, 74.79 ± 6.90 kg). The 35 participants were divided into Pass and Fail groups (20 and 15, respectively). We measured body composition, physical strength, and salivary cortisol and (IgA) concentrations (pre- and post-G-tests). Statistical significance was set at p < 0.05. Regression analysis revealed a significant difference between the body composition model (p = 0.021) and the saliva analysis model (p < 0.001). Moreover, we observed a significant difference in skeletal muscle mass, body mass index, salivary flow rate, salivary cortisol levels, and salivary IgA concentration and secretion rate between the groups after the G-test. In addition, we observed a significant correlation between the G-test results and saliva analysis. Gravitational acceleration acts as a stressor on the body and triggers an immunological response. Our findings may be used to evaluate the health of pilots. Future research should focus on the interactions between physiological and environmental factors within the G-force environment to gain a deeper understanding of their effects on the health, functioning, and performance of pilots. In addition, ascertaining the long-term effects of repeated G-force exposure on immune function may be crucial, thus requiring further research.