Abstract
Background: Exposure to high +Gz provoke a unique physiological stress and various potential harmful effects in humans. Despite the importance of monitoring physical alterations related to +Gz exposure, there have been only a few studies concerning the physical status of human centrifuge trainees.
Objective: We investigated alterations in serum biochemical and complete blood count parameters occurring in subjects exposed to high +Gz.
Methods: One hundred fifty eight flight-naive subjects (group A), who had never experienced flight or centrifuge training, and 80 experienced jet fighter pilots (group B) were exposed to +6Gz and +7.3Gz, respectively. Blood samples were obtained before and immediately after the centrifuge runs.
Results: In group A, creatine phosphokinase (CPK) was increased from a mean of 136.56±17.87 IU/L pre-run to 236.33±23.71 IU/L post-run, a significant 73.1% increase. In 26 of 158 (16.5%) group A subjects, CPK was elevated over 400 IU/L, with a maximum of 1904 IU/L. Δ CPK of group A (99.77±16.94 IU/L) was significantly greater than that of group B (0.53±5.67 IU/L). In addition, Δvalues of total protein, white blood cell count, red blood cell count, hemoglobin, and hematocrit of group A were significantly greater than those of group B.
Conclusion: We demonstrated that the extent of post-centrifuge CPK elevation and hemoconcentration was significantly greater in flight-naive subjects than in experienced jet fight pilots. Our data raise the possibility that the level of experience in flight and centrifuge training can affect the extent of +Gz-induced alterations in blood constituents.