## 3 Results
### Heart Rate Variability Measures  
The results of the repeated measures ANOVA for the monitored Mean RR, SDNN and RMSSD parameters, considering the interaction of the executed flight and monitored group of subjects, show that there is statistically significant difference between Gr. A and Gr. B with respect to the distribution of respective HRV measures during the training. Specific results of the repeated measures ANOVA for Mean RR show \(F(5,1160)=26.504\), \(p\approx 2\times 10^{-25}\); for SDNN \(F(5,1160)=5.545\), \(p\approx 1.6\times 10^{-4}\) and for RMSSD \(F(5,1160)=11.337\), \(p\approx 7.7\times 10^{-9}\). Mean RR, SDNN a RMSSD distribution during the training of both groups is depicted in Figure 3 by means of error plots. The results of post-hoc multicomparison analysis are shown in Figure 4. Note that increase in Mean RR indicated decrease in heart rate (beats per minute) a vice versa. The monitored HRV measures for Gr. A indicated uniformly that the initial contact with glass-cockpit arrangement in form of simulated flight (Fl. 18) was the least stressful for the group (see Figure 4A-C). Fl. 11 measurement also showed significantly higher values of the monitored parameters among all monitored HRV measures (except for RMSSD, where no statistically significant difference was identified between Fl. 11 and Fl. 19). During Fl. 11 and Fl. 18 measurements, the subjects exhibited statistically significant R-R interval separation (indicating lower heart rate) and higher short-term and long-term heart rate variability. For this group, however, it was not possible to determine the level of workload based on the HRV between Fl. 2 and the real flights. This could mean that the workload was at the same level, or there was not enough evidence for decision about the difference between these flights. The results for RMSSD parameter, however, showed that during real flying with glass-cockpit (Fl. 19) the subjects exhibited no statistically significant difference between Fl. 11 and the rest of the measured flights. Having a look on Figure 4C, this flight appeared to be intermediate between low and high workload for Gr. A. Because it was not possible to reliably distinguish respective flight from other flights, such as Fl. 2, Fl. 12 and Fl. 17, by means of SDNN and Mean RR, it is possible to conclude that Fl. 19 did not exhibit the assumed workload stemming from the experiment. With the experiment setting, it was assumed that glass-cockpit would play the role of influencing factor, affecting psychophysiological condition or workload. The presented results, however, did not support this. Even more, the results from the perspective of subjects' psychophysiological condition exhibited rather an improvement with the cockpit ergonomics change. All Gr. B HRV measures results are of more complex nature. Assessing the training by pairwise comparison evaluation (see Figure 4), it is possible to claim that the subjects exhibited the lowest workload during the flights Fl. 2, Fl. 11 and Fl. 22. These flights were executed on flight simulator and showed no statistically significant difference in Mean RR and SDNN. In case of short-term variability, i.e., RMSSD (see Figure 4C), there was statistically significant difference between Fl. 11 a Fl. 22. In this case, it was difficult to determine the sequence of the simulated flights only by workload change  
Figure 3: Mean RR (**A**), standard deviation of NN intervals (SDNN) (**B**), root mean square of successive RR interval differences (RMSSD) (**C**) and composite Error (**D**) distribution with no additional training for glass-cockpit (Gr. A) and with additional training for glass-cockpit (Gr. B). (S—simulated flight, R—real flight, A—analog cockpit, G—glass cockpit, Fl. #—flight number, *—significant difference between groups). based on HRV measures. It is, however, possible to claim that there was no statistically significant difference between Fl. 2 and Fl. 22 in any HRV parameter, i.e., unlike for Gr.