Salivary alpha-amylase activity and stress in Japan air self-defense force cargo pilots involved in Iraq reconstruction.

OBJECTIVES: This study aimed to verify whether salivary α-amylase enzyme activity (Amy) is useful as a biomarker of stress in pilots working in a stressful environment. METHODS: The subjects in this study were nine Japan air self-defense force pilots who participated in Iraq reconstruction support activity in Kuwait. Amy was measured using a portable salivary amylase monitor at preflight, postflight, and on stand-by day. In addition, the state-trait anxiety inventory was administered with state scores (STAI-S) compared to Amy levels. RESULTS: There were greater differences in Amy levels at baseline compared to STAI-S scores between subjects on the stand-by day. Amy levels at preflight tended to increase compared to those on stand-by day as did STAI-S. The change in Amy level at postflight varied among the pilots. The Amy levels of four subjects at postflight were elevated compared to levels at preflight, while the STAI-S scores for all pilots at postflight were lower than at preflight. CONCLUSIONS: This study suggests that the Amy level of pilots can reflect subtle individual differences in response to the psychological and physiological stress of a flight task. Thus, monitoring Amy level may be useful for stress evaluation of pilots working in a stressful environment, providing data that might be used as an impetus for addressing stress management for this population.