Journal of Ergonomics

Introduction: Advances in technology and the use of complex systems at work have imposed high mental workloads to operators; so, continuous monitoring of mental workload can help to prevent mental problems and maintain mental health. Therefore, this study aimed to investigate the impact of mental workload on physiological and subjective responses.

Methods: This cross-sectional descriptive-analytical study was performed on 16 healthy university students in 2014 at a laboratory setting. Physiological parameters of surface electromyography and electrocardiography in six blocks (resting, high mental work, moderate, low, very low and recovery) were measured using NeXus-4. After performing each block, the NASA-TLX questionnaire was completed. Statistical analysis was conducted using SPSS software version 21.0. A 5% significance level was adopted in all the tests.

Results: The results showed significant differences for the average score of NASA-TLX between the different levels of mental work load (P < 0.05). Also, the analysis of repeated measures variance showed significant differences for heart rate and heart rate variability parameters in the six blocks (P < 0.05), but no significant difference was observed for the shoulder muscles activity.

Conclusions: Different levels of mental work load can impact on people's subjective responses and some of their physiological responses. Thus, in such workplaces, it will be necessary to conduct an ergonomic program to manage mental health.