## 3 Results  
In this case, 50% of the heart rates were found between the 1 st (25%) and 3 rd quartile (75% The comparisons of the measurement conditions (Friedman test) without noise among each other, i.e., (a) without headphones, (b) headphones with noise canceling and (c) headphones without noise canceling, showed no significant differences in any of the groups (Table 1). Figure 1: Oscillograph curves and spectral frequency representations for the first ten seconds of the sound stimuli used in the measurement conditions for both audio stereo channels. (**A**) pink noise, (**B**) relaxation music, (**C**) classical music, (**D**) heavy metal music, (**E**) modulated pink noise at 117 bpm, (**F**) modulated pink noise at 139 bpm, (**G**) modulated pink noise at 174 bpm. Table 1 also presents the comparisons of the effects of the measured sound conditions on HR per group (within-group differences). Group 1 (\(p\leq\) 0.001) presented the most significant group differences (\(p\leq\) 0.05-0.001) between the measurement conditions. Most frequently, the 117 bpm measurement condition differed significantly from the other measurement conditions (\(p\leq\) 0.05-0.001; HP without NC, HP with NC, classical music, relaxation music, heavy metal music, 139 bpm and 174 bpm). In addition, the measurement condition \"pink noise\" was often significantly different from the other conditions (\(p\leq\) 0.05-0.001; without HP, HP without NC, classical music, heavy metal music, 139 bpm). The median difference (Table 1) of all the significant HR differences was a maximum of 6 bpm and a minimum of 1 bpm. In group 2 (\(p\leq\) 0.001), significant pairwise comparisons (\(p\leq\) 0.05-0.001) were present only in the following comparisons: without HP vs. 117 bpm, HP without noise canceling vs. 117 bpm and relaxation music vs. 117 bpm, with the median HR differing between 4.5-3 bpm between these significant differences. In group 3, the Friedman test was not significant (\(p\leq\) 0.64) and, consequently, there were no group differences observed. The interaction effect between group and gender was F = 0.11 (\(p\) = 0.74). In conclusion the different gender ratio did not have an effect. Between-Group Differences  
Table 2 contains the group-specific median values as well as the data of the 1 st and 3 rd quartiles. This table also contains the \(p\)-values of the group comparisons of the Kruskal-Wallis test for each sound condition as well as the corrected \(p\)-values of the pair comparisons after Bonferroni-Holm correction (between-group differences). Furthermore, the \(p\)-values of the Friedman test and the subsequent multiple pairwise comparisons, according to Conover-Iman including Bonferroni-Holm correction, across all measurement conditions per group are shown in this table. When the three subject groups were compared for each measurement condition, group differences were evident (\(p\leq\) 0.05-0.001). The subsequent pairwise comparison illustrates a significant group difference (\(p\leq\) 0.05-0.001) in each parameter between the first and second group, i.e., between the young and older healthy adults. Only in the case of the continuous noise at 117 bpm did the heart rate additionally differ between groups YA and PD with \(p\leq\) 0.04. In each comparison, the HR of the subjects from group YA was at least 8 bpm above the median of the subjects from group EA and group PD, respectively. The average HR of each subject in their group is shown in Figure 2, where the divergent heart rates between the three groups can be seen. While the median HR in group YA ranged 86-92 bpm for all measurement conditions, it ranged 75.5-80 bpm in group EA and 80-84 bpm in group PD.