Pacing-induced palmar sweating evaluated by unique hygrometer: possible implications of sympathetic activation during tachycardia

State Anxiety Dependent on Perspiration during Mental Stress and Deep Inspiration

In this study, we focused on two types of perspiration, one triggered by anticipatory anxiety and the other by voluntary deep inspiration. We have previously found that the anticipation of anxiety causes increases of respiratory frequency, and that these increases are related to an activation of the temporal pole and amygdala in humans. Our interest is in the difference between the two natures of perspiration, both of which are closely related to respiratory responses. The level of sweating responses did not differ between deep and active inspiration or between three trials. This means that there was no habituation with repetitive trials for voluntary breathing. On the other hand, sweating responses during anticipation of anxiety showed habituation with repetitive trials. Habituation and nonhabituation differences with respect to these two characteristics of perspiration could be the result of differences in the related central networks. The former might be involved cortical structures associated with conscious changes of respiration. The latter was induced unconsciously, and this unconscious response is similar to the respiratory response during anticipatory anxiety, which may be related to the activation of the limbic system. Further, there was a positive correlation found between the amount of perspiration response and the state anxiety scores in deep inspiration, and also in trial 1 of the anticipatory anxiety experiment. Both types of responses were related to the individual state anxiety scores, and this may contribute to the defense mechanism with regard to adjustments to changes in the outer environment and situations.