Emotional states are characterized by changes in the functioning of the heart: for example, when you’re excited and happy your heart rate and blood pressure go up, when you’re down they go down. Music, in its capability to evoke emotions can therefore directly influence the heart. Recently, Stefan Koelsch and Lutz Jäncke published a comprehensive review paper in the European Heart Journal summarizing current understanding on how music influences the heart, and suggesting future directions for this exciting field of research.
The effects of music listening can be seen on multiple levels of physiology: heart rate, heart rate variability (the variation in beat-to-beat intervals), blood pressure, as well as breathing rate and depth. For example, in healthy individuals, “chills” or experiences of intense pleasure while listening to music are associated with increase in heart and respiratory rate, especially if the chills are strong enough to raise the hair on the arms for instance. In general, exciting music increases blood pressure and heart rate more than relaxing music, as does listening to any music at all (or even just a beat) when compared to silence. However, whether a music piece is ultimately relaxing or not, depends on personal preference, not just acoustic characteristics. Music directly touches our hearts, reflecting the individual emotional effects of the piece in question.
If this link exists, could music listening then be used to manage and even treat medical conditions that have an effect on the heart? There is quite convincing evidence that music can be used to reduce anxiety and to manage pain in a number of clinical settings. Reduction of anxiety through music listening can also be connected to decreases in blood pressure and heart rate - an outcome that may prove especially important for heart patients. A Cochrane review on intervention studies on coronary heart patients found that in addition to stress reduction, listening to music significantly reduced the systolic blood pressure. However, the reviewed studies reported interventions that lasted only up to 3 days, and therefore, the long-lasting results of music listening on blood pressure in healthy people or heart patients are not yet known.
Also individuals with depression may experience heart-related benefits from music listening. According to the review by Koelsch and Jäncke, depression may double the risk for cardiovascular disease. Support for heart health might be an additional benefit of music therapy, that has been found to be effective in amelioration of symptoms related to mood.
One debated topic in research is whether heart rate could become synchronized to the beat in music, and whether music can influence this irrespective of emotions. Typically, exciting music with a faster tempo raises heart rate more than relaxing music with a slower tempo. Some studies (Bernardi et al, 2009 and Bernardi L., Porta, C., Sleight P., 2005) have suggested that music could directly increase arousal mainly due to its tempo and not because of any associated emotional reaction, i.e. tempo first causes physiological arousal, which then perhaps leads to emotional appraisal, and not the other way around. These conclusions have however been criticized, and recently, one study showed that differences in tempo did not result in changes in heart rate when the stimuli were otherwise identical (for example, equally pleasurable and arousing to the listener). More research is therefore needed to determine the links between emotional arousal and the effects of music on heart rate.
In summary, there is convincing evidence that music listening has an effect on heart function. This link also shows promise in clinical applications. However, there are many differences in the methods used and the experimental settings employed between studies looking at these effects. As a result, more evidence is needed before clear-cut conclusions or recommendations can be made. Future studies should more carefully examine factors such as musical characteristics, styles, personal preferences, and use combinations of several measures for physiological outcomes of music listening. The Sync Project platform could provide one way of obtaining just this kind of extensive data on the link between music listening, musical preferences and physiological reactions.