The Effect of Music on the Human Stress Response Nov 7, 2013 22:14:08 GMT
Post by Admin on Nov 7, 2013 22:14:08 GMT
As listening to music has the capacity to initiate a multitude of cognitive processes in the brain , it might be assumed that music also influences stress-related cognitive processes and, as a consequence, physiological responses. Previous investigations found reductions in perceived levels of psychological stress, increased coping abilities, or altered levels in perceived relaxation after listening to music in the context of a stressful situation [7,33]. Another line of research has focused on the effects of music on anxiety, which may be considered an adaptive response to the experience of stress. Given that music listening can trigger activity in brain regions linked to the experience of (intense) emotions [8,34–36], listening to music might also modulate anxiety levels induced by the experience of stress. Indeed, a decrease in anxiety after listening to music is the most consistent findings reported in field studies with patients [22,37,38] and laboratory-based studies [26,39]. Nevertheless, not all investigations found anxiety reductions through music listening [40–42]. Also here, no final conclusions can be drawn whether or how music is able to influence cognitive and emotional components of the stress response.
In sum, it appears that listening to music has the inherent ability to decrease the psychobiological stress response. However, due to the fact that the existing literature is not complete and often appears as inconsistent, definitive conclusions about the beneficial stress-reducing effect of music may be too premature. In light of these considerations, we set out to examine the effect of listening to music prior to a standardized stressor across neuroendocrine, autonomic, cognitive, and emotional domains of the human stress response in healthy participants in a laboratory setting. We put a special emphasis on the control of known influencing factors of the stress response and music effects, i.e. depression, anxiety, chronic stress, and emotion regulation traits. To the best of our knowledge, such an endeavor has not been attempted thus far. We hypothesized that those participants who listened to relaxing music prior to the stress task would show a different stress responses in terms of cortisol, salivary alpha-amylase, heart rate, respiratory sinus arrhythmia, subjective perception of stress, and anxiety when compared to non-music control groups, i.e. an acoustic control condition (sound of rippling water) and a control condition resting without acoustic stimulation.
Figure 4. Salivary alpha-amylase activity in response to the TSST.
Salivary alpha-amylase activity in response to the TSST (means ± SEM) in the experimental group listening to relaxing music (RM), the control group listening to sound of rippling water (SW), and the control group resting without acoustic stimulation (R).
sAA activity increased significantly over the course of the stress task (F(2.62/146.82)=15.60; p<0.001; η2=0.218). Without the inclusion of the control variables (i.e. BDI, ERQ, STAI-trait, TICS), repeated-measures ANOVA revealed no significant group differences (group-by-time interaction: F(5.24/146.82)=1.19; p=0.318; η2=0.041). Also with the inclusion of the control variables, we found were no significant differences in sAA activity between groups (group-by-time interaction: F(4.96/119.01)=1.4; p=0.23; η2=0.055) (Figure 4). Univariate analyses however revealed a significant difference in the recovery delta between groups (F(2/48)=4.13; p=0.022; η2=0.147). Single group comparisons revealed a significant difference between RM and R (F(1/31)=0.547; p=0.026; η2=0.15) and between RM and SW (F(1/29)=4.7; p=0.039; η2=0.139) in the recovery delta; sAA activity in the RM condition is back at baseline at T4 (+ 25 min), compared to R or SW at T5 (+ 40 min).
Figure 5. Heart rate in response to the TSST.
Heart rate in response to the TSST (means ± SEM) in the experimental group listening to relaxing music (RM), the control group listening to sound of rippling water (SW), and the control group resting without acoustic stimulation (R).
Cardiac measures changed significantly over the course of the experiment over time (HR:F(3.16/151.77) = 122.05; p<0.001; η2=0.027; RSA: F(3.3/158.49)=20.41; p<0.001; η2=0.298). HR and RSA showed mirrored stress responses (FIGURES 5 and 6). Without the inclusion of the control variables (i.e. BDI, ERQ, STAI-trait, TICS), repeated-measures ANOVA revealed no significant group differences concerning HR (group-by-time interaction: F(6.32/151.77)=0.66; p=0.692; η2=0.027) or RSA (group-by-time interaction: F(6.6/158.49)=0.86; p=0.533; η2=0.035). Also with the inclusion of the control variables, groups did not significantly differ over the course of the experiment concerning HR (group-by-time interaction: F(5.73/103.2)=0.6; p=0.72; η2=0.032) or RSA (group-by-time interaction: F(5.76/103.7)=0.96; p=0.456; η2=0.05). However, groups significantly differed in the recovery delta of RSA (5 min after cessation of TSST) (F(2/40)=4.06; p=0.025; η2=0.169): Single group comparisons revealed a significant difference between SW and R (F(1/27)=6.70; p=0.015; η2=0.199), suggesting a faster recovery of SW after the TSST in RSA when compared to R.
We observed a differential influence of music listening on autonomic activity: music resulted in a faster autonomic recovery after stress compared to the control groups. This partly corresponds with findings from an investigation by Arai et al.  who found significantly decreased sAA levels at wound closure in patients who listened to intra-operative music when compared to a non-music control condition. Music might thus facilitate autonomic recovery from a stressor in comparison to listening to non-musical sounds or no acoustic stimulation. The fact that our finding only showed a statistical trend narrows its relevance, however. Other investigations assessing the effects of music on the ANS (e.g. via epinephrine and norepinephrine) have found no beneficial effects [37,86]. As for cardiac measures, we found a decrease in HR and an increase in RSA in response to RM, SW, and R. After stress exposure, we found an increase in HR and a decrease in RSA. On the one hand, these findings correspond to investigations that found an increase of parasympathetic activity in response to sedative music listening [87–89]. On the other hand, our results corroborate findings from studies reporting decreased parasympathetic activity in response to stress [90,91]. As with sAA, we found a trend for a faster recovery of the RSA in the music group when compared to the resting control group. It appears that music listening might be effective in accelerating the recovery process of the parasympathetic branch of the ANS. It is interesting, however, that the sound of rippling water was even more effective than music in returning RSA levels back to baseline. Clearly, further studies are warranted for further eliciting the differential physiological effects of music and non-music acoustic stimulation.
Music listening had no differential effect on psychological measures (stress perception or anxiety) in comparison to the two control conditions. This is not in line with investigations that report listening to music to be effective in reducing psychological stress  or anxiety [26,37–39]. One explanation might be that music listening may only reduce psychological stress / anxiety in the presence of a relatively mild stressor. It might be the case that the stressor in our study (i.e. the TSST) was too strong. Knight and Rickard , who were using a (mild) cognitive stressor in the laboratory, found anxiety-reducing effects of music listening prior to stress. MacDonald and colleagues found similar effects only in those patients who had a minor surgery (mild stressor) and not in those who had a major surgery . Evans , finally, systematically reviewed studies of the effectiveness of music interventions for hospital patients. He found that music listening was effective for the reduction of anxiety during normal care delivery (which may be considered as mild stressors), but not for patients undergoing invasive or unpleasant procedures (strong stressors). In contrast to those findings, however, patients in the study by Allen et al. were experiencing “…a high level of stress and anxiety...”  related to surgery, so that one may assume that this was a strong stressor. Still, music was effective in decreasing perceived stress levels in that study. However, patients were allowed to listen to their own choice of music. It might be argued that not the music itself, but the positive memories associated with it caused this effect. What is more, control patients did not wear headphones and were therefore exposed to the sounds of surgery, thus further inducing stress in the control group. Future studies are needed to test for the assumption that music listening might only reduce stress related psychological processes and anxiety in the context of mild stressors.
Taken together, our results seem to indicate that pre-stress music listening might not be effective in reducing the biopsychological stress response, but might, in contrast, add to or facilitate a stress response. However, our results may also be interpreted in the light of another explanation: it may be that the participants in the music group were actually so relaxed that the subsequent stress induction was incompatible with this state of relaxation, and that they produced an increased stress response as a consequence. We might have therefore measured the effect of the contrast between a relaxing and a stressful state rather than the preparatory effects of relaxing music on the subsequent stress response. This notion is supported by the greatest increase in stress perception in the relaxing music group. Future studies should follow-up on this explanation and further dissect the effects of preparatory music listening on stress responses.
Thoma MV, La Marca R, Brönnimann R, Finkel L, Ehlert U, et al. (2013) The Effect of Music on the Human Stress Response. PLoS ONE 8(8): e70156. doi:10.1371/journal.pone.0070156