AhReum Joung, Alisha Chu, Ian Bledsoe

CU Boulder, Fall 2002

We tested the effects of different types of music on heart rate and blood pressure. In a previous experiment, exercise was found to significantly affect blood pressure and heart rate. This study was carried out as a sort of extension of that investigation, but from a different angle. Physiological effects are clearly present after physical exertion; our question became one of the effects of mood on these same physiological phenomena. If there is a subjective sensation that music affects one’s mood, can physiological phenomena be observed corresponding to that change in mood? It was hypothesized that a significant difference would be observed both in the heart rate and blood pressure of listeners after listening to the musical selections as compared to control conditions

Two musical selections were chosen in juxtaposition with each other in the hopes that the greatest possible variability would be observed in the subjects’ reactions to them. The first selection was the first movement of Bach’s Goldberg Variations for piano ("Aria"), recorded by Glenn Gould in 1982. The second selection was the song, "Action Satisfaction" from Jurassic Five’s 1997 album "Jurassic 5 EP." Factors that may contribute to the subjective perception of the two selections as either "relaxing" or "exciting" are as follows. Firstly, the tempi of the two pieces are very different. The Bach has a tempo of 34 beats per minute, whereas "Action Satisfaction" has a tempo of 96 bpm. The texture of the Bach is much simpler as well, consisting only of solo piano. "Action Satisfaction," on the other hand, consists of a much thicker texture with voices, drums, bass, and other instruments and sounds inserted throughout. Also, there is a constant drum beat in the Jurassic 5 which adds to the busy, exciting nature of the music.

Subjects were instructed to lie down on a table so as to minimize physical exertion that might skew the results. The room in which the experiment was conducted was the same for all the subjects. There was no stimulus such as noise to distract the subjects. Initial readings of heart rate and blood pressure were taken before the subjects listened to music. Then, the same readings were taken while the subjects listened to the two musical selections. In order to standardize the results as best as possible, the subjects listened to each selection for exactly 60 seconds, after which the readings were taken as they continued to listen to the music. A pause of three minutes was inserted between the playing of the different selections of music in order to minimize the influence of the previous music on the reactions to the second selection. It was predicted that the Bach would decrease heart rate and APm as compared to the same readings taken under control conditions (with no music). It was further predicted that the Jurassic 5 would increase these same variables as compared to the control group.

Our results indicated that there was a significant difference between the heart rate of subjects when listening to Bach (mean=59.2 bpm) as compared to listening to Jurassic 5 (mean=67.8 bpm; t=-9.86, P<.05) and when listening to Jurassic 5 as compared to listening to no music (mean=62.4 bpm; t=-4.32, P<.05). No significant effect was found on APm after listening to the music.

Our results were partially inconsistent with our predictions. One potential problem in our methodology was the fact that we took heart rate and blood pressure readings simultaneously. Some of the subjects may have experienced some apprehension about the pressure or discomfort of the sphygmomanometer used to take blood pressure readings, and this may have had the effect of raising their heart rate. The sample size (N=5) was also relatively small, and clearer results may have been observed had it been larger. Clearer results might also have been observed if the subjects had been allowed to listen to the music for a longer period of time before the readings were taken. It was interesting that a significant difference was found between the Bach and the Jurassic 5 groups, but not between the control conditions and the listening to Bach. It is possible that the response to relaxing music takes longer to register in heart rate, whereas the effect of increasing heart rate in response to faster music occurs more quickly. Since there was a significant increase in HR, but not Apm, there is a possible decrease in TPR. This decrease may be due to dilation of capillaries or other major veins and arteries. Were the experiment to be repeated, it might be designed so that the same music would be tested at multiple time intervals in order to graph the effects of the same piece over time. Also, testing the same subjects on different days might control for other factors that affect heart rate in a particular session (e.g. stress over exams, exhaustion, etc.)