Effect of psychological stress on the salivary cortisol and amylase levels in healthy young adults.

OBJECTIVE Saliva sampling has the advantage that it is non-invasive, making multiple sampling easy and stress free. We examined the effects of psychological stressor and soother on the salivary cortisol and amylase levels in young adults, and compared the characteristics of these parameters. DESIGN The subjects completed the trait version of State-Trait Anxiety Inventory (STAI) to assess the predisposition to personal anxiety. The video of corneal transplant surgery was served as the stressor for 15 min. A scenic beauty video viewing was also used as the soother. Unstimulated whole saliva was collected every 3 min throughout the session. RESULTS The amylase level was significantly increased just after the beginning of the stressful video viewing, and immediately returned to the pre-stress level just after the end of the video viewing. The cortisol level was also increased, but to a lesser extent compared with that of amylase. The latency time to the peak level for cortisol was longer than that of amylase. The carry-over effect was not observed in the amylase response but was in cortisol. Although the correlation between the amylase level and the STAI score was highly significant, cortisol level did not. In addition, soothing video viewing significantly decreased the amylase level, but did not affect the cortisol level. CONCLUSION Salivary amylase level was more significantly increased and reacted more rapidly than cortisol by psychological stressor, suggesting that it is a better index of stress. Furthermore, it is suggested that the enzyme is a soothing or relaxation index.