CARDIOVASCULAR, HORMONE, AND LIPID RESPONSES TO STRESS INDUCED BY VIRTUAL CRANE HANDLING

Objectives: The aim of the study was to test whether a mixed-mock-up-simulator (MMU-simulator) is suitable for on-the- job training by measuring stress reactions induced by handling a crane in a virtual environment in subjects not experienced in crane operation. Materials and Methods: A MMU-simulator in a virtual environment was developed. Twenty three individuals were randomly divided into Group 1 (n = 13) and Group 2 (n = 10). They had the task of transporting a weight over barriers with a virtual crane twice in two 15-min intervals with a 15-min break in between. Acoustical and optical disturbances were generated as an additional strain for Group 1 in the second interval and for Group 2 in the first interval. Heart rate (HR) and blood pressure (BP) were measured consecutively in both groups, blood sampling was performed in Group 1. Plasma concentrations of stress hormones and lipids were analyzed. Data were calculated as the percentage of baseline values. Results: Compared to rest courses, strain led to a significant increase in HR and BP except diastolic BP in Group 2. Apart from an increased systolic BP under additional stress in Group 2, no significant differences were found between the two strain courses. Concentrations of epinephrine showed the highest increase under strain with a mean of 67%. The mean increase in norepinephrine and cortisol was 23% and 7%, respectively, whereas a 4% increase was observed for total cholesterol and high density lipoprotein cholesterol. These differences between "Rest" and "Strain" were significant. After adjusting for total plasma protein concentration, stress hormones, but not lipids, were still significantly higher during strain. Conclusions: The elevation in lipids during acute stress could be interpreted as an effect of hemoconcentration due to vasoconstriction by catecholamines. The significant increase in cardiovascular parameters and stress hormones during the tasks demonstrate that working in a virtual environment generates mental strain and that the developed MMU- simulator appears to be a promising device for on-the-job training. However, further research is necessary to validate the usefulness of virtual training by means of a comparative study of virtual and real-world training.