Basic study of a ship navigator's mental workload using salivary NO\documentclass{article}\usepackage{amsmath}\usepackage{amssymb}\usepackage{amsbsy}\usepackage{amsfonts}\pagestyle{empty}\begin{document}$_{3}^{-}$ \end{document}

Evaluation of the mental workload during training for ship handling has usually depended on professionals (captain, pilot) who have lots of experience on board. We are attempting to evaluate a ship navigator's mental workload based on a physiological index. The physiological indices, namely heart rate variability (R–R interval), nasal temperature, and salivary amylase, are good indices for reading the mental workload during ship handling. Moreover, we find the possibility of using salivary NO$_{3}^{-}$ as a good index for evaluating the ship navigator's mental workload. Salivary NO$_{3}^{-}$ is expected to have a specific characteristic to represent quick response on the spot and the trend. We confirmed the response of students during simulator training, and then carried out the experiment on professionals on a real ship. We propose that salivary NO$_{3}^{-}$ can show a ship navigator's stress for ship handling in the simulator and on a real ship. This work to evaluate the ship navigator's mental workload using salivary NO$_{3}^{-}$ is the first attempt worldwide. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.