Effects of Arithmetic Tasks on Autonomic Nervous System Activities

Abstract

Currently, numerous complexities are increasingly leading to mental stresses for professionals. It is necessary to develop techniques and equipments to evaluate mental stress. Our past study revealed that task-induced physiological changes did not return to the baseline level. In this study, we investigated the relationship between the physiological responses and subjective feelings during the performance of mental tasks and after the tasks. We recorded the physiological responses and subjective feelings of 18 healthy young males while they successively performed arithmetic tasks at 4 levels of difficulty and while they rested between each task. The subjective feelings were analyzed by factor analysis, and the relationships between physiological responses and the factor scores were determined. From the results, during the tasks, RR intervals (RRI) and skin potential level (SPL) were correlated significantly with the factors of satisfaction and concentration-vigor, and tissue blood flow of nose (TBF_N) and photoelectric plethysmogram (PTG) decreased below the baseline level. No significant correlation was found between physiological responses and scores of feelings after the tasks. RRI and SPL recovered to the baseline level immediately after the tasks. However, TBF_N and PTG did not recover to the baseline level soon.