INDEXES OF MENTAL WORKLOAD IN A COMPLEX TASK ENVIRONMENT

The aim of the present experiment is to evaluate heart rate variabilit y (HRV) and cortisol as indices of mental workload in a complex enviro nment. Heart rate was continuously recorded during flight scenarios th at differed in difficulty. The HRV nicely reflected the changes in dif ficulty. The results support the idea that HRV is a sensitive index fo r mental workload when tasks are highly demanding and subjects are mot ivated to exert additional effort whenever the task becomes more deman ding. Cortisol was only slightly increased on the experimental day com pared to the training day. On the experimental day, post-task levels d id not differ from pre-task levels. The level of cortisol in saliva wa s, however, related to overall task performance. Subjects who had a hi gh level of cortisol had a low level of performance.