Physical Condition Does Not Affect Gravity-Induced Loss of Consciousness during Human Centrifuge Training in Well-Experienced Young Aviators

BACKGROUND: Consensus on whether physical condition affects the risk of gravity-induced loss of consciousness (G-LOC) has not been reached, and most previous studies about the issue did not include well-experienced aviators. We compared the physical conditions of well-experienced young aviators according to the occurrence of G-LOC during human centrifuge training. METHODS: Among 361 young male aviators on active flight duty with experience in high performance aircrafts for at least 2 years, 350 had full data available and were reviewed in this study. We divided the aviators into the G-LOC group and the non-G-LOC group according to their human centrifuge training results. We then compared their basic characteristics, body composition, physical fitness level, and pulmonary function. RESULTS: Twenty nine aviators (8.3%) who experienced G-LOC during human centrifuge training in their first trials were classified into the G-LOC group. There was no difference in physical condition of aviators between the two groups. CONCLUSIONS: Young aviators with experience in G-LOC showed no difference in physical condition such as muscle mass, strength, and general endurance from the aviators with no such experience. Although more studies are needed, physical condition does not seem to be a significant determinant of G-LOC among the experienced aviators.