Abstract
Operating an aircraft imposes significant physical and mental demands on pilots, particularly those in military aviation. These challenges include circadian disruptions, irregular working hours, and exposure to G-forces. This study investigates the acute metabolic effects of flight in the A-29 fighter pilots of the Brazilian Air Force (FAB). Blood, urine, and saliva samples were collected from 32 pilots, trainees (n = 12; aged 23-26 years) and instructors (n = 20; aged 25-41 years), immediately before and after flights. Assessments included anthropometric measurements, complete blood count (CBC), circulating endothelial cells (CECs), coagulogram, lipidogram, urinalysis, and nuclear magnetic resonance (NMR)-based metabolomics. After flights, trainees showed a 12% increase in the number of segmented neutrophils, while instructors exhibited a 15% increase in the number of lymphocyte counts. Serum lactate levels decreased in both groups (23% in trainees and 12% in instructors). Salivary glucose increased by 49% in trainees, whereas instructors demonstrated decreases in metabolites such as choline (23%) and lactate (15%). Urinary trigonelline levels increased by 53% in instructors. The observed changes were more pronounced in instructors vs trainees, indicating a degree of metabolic adaptation associated with greater flight experience. These findings highlight NMR-based metabolomics as a valuable tool for monitoring acute metabolic changes in fighter pilots.