the position and modalities of the different sensors, generating a wide number of possible measurement configurations.

In a second phase, a final prototype has been implemented allowing the measurement of the selected most important measurements, with the final configuration of the sensors. It consists in a uniform vest that embeds all the electronics and signal processing algorithms to assess and represent the different stress levels in both the soldier and command displays.

This manuscript is mainly focused on the work done during the first phase, the one targeting the selection of the main biomedical parameters for assessment of mental stress and workload. The second phase addresses the construction of sensorized vest and, its validation and the usability study is out of the scope of this manuscript and it will betwo different games. These games were selected in order to put the subject at the limits of mental calculus. The first game consists in making a set of quick mental sums. A set of digits to be added appears on the screen, and the subject has to click on the correct solution. The time available to solve each problem varies along the experiment, being decreased when the subject answers right, and increased when he/she answers wrong. The idea is to put the subject in a high level of mental activity, independently of his/her calculus ability. This game was played since 80 sums from two to five digits were carried out. The second game consists in a Tetris-based game, in which again the objective is to seek the limit