|Year : 2015 | Volume
| Issue : 4 | Page : 93-100
Immediate Effect of Indian Music on Cardiac Autonomic Control And Anxiety: A Comparative Study
Karuna Nagarajan, Thaiyar M Srinivasan, Nagendra Hongasandra Rama Rao
Department of Research, Division of Yoga and Life Sciences, Swami Vivekananda Yoga Anusansadha Samsthana (S-VYASA) University, Bangalore, Karnataka, India
|Date of Web Publication||21-Dec-2015|
Division of Yoga and Life Sciences, Swami Vivekananda Yoga Anusansadha Samsthana (S-VYASA) University, # Ekanth Bhavan, Gavipuram Circle, KG Nagar, Bangalore - 560 019, Karnataka
Source of Support: None, Conflict of Interest: None
Background: Many studies have shown that music experience is the key to develop future therapies in order to prevent the development of cardiovascular disorders. Aims: The present study aimed to evaluate the effects of heart rate variability (HRV) on exposure to Indian raga Bhupali with that of two control groups of pop music and no music or silence in a sample of healthy subjects. Materials and Methods: Autonomic functioning, anxiety level, and subjective feeling were assessed in 28 healthy subjects, both male and female [group mean age ± standard deviation (SD), 19.68 ± 2.57] during three sessions. The three sessions were the musical session intervention with the Indian raga Bhupali, pop music with steady beats, and "no music session." Assessments were made before (5 min), during (10 min), and after (5 min) in each of the three states on 3 separate days. Results: During the Indian raga, there was a significant decrease in the low frequency (LF) power (P < 0.01) and increase in the high frequency (HF) power (P < 0.01) in the frequency domain analysis of the HRV spectrum. There was also a significant decrease in the mean heart rate (HR) (P < 0.01) and a significant increase in the NN50 (P < 0.05) and RMSSD (P < 0.05) in the time domain analysis of HRV. Both frequency and time domain measures are indicative of parasympathetic activity. The anxiety level significantly (P < 0.001) decreased post the Indian raga session and significantly (P < 0.01) increased post the pop session. The subjective assessment of perceived feeling using the visual analog scale (VAS) comparing Indian raga with pop and silence sessions showed a significant difference of feeling positive (P < 0.01). Conclusions: Exposure to the Indian raga Bhupali reduced sympathetic activity and/or increased vagal modulation with reduced anxiety levels and subjective assessment of perceived feeling showed positive changes.
Keywords: Aesthetic mood, Heart Rate Variability (HRV), Indian raga Bhupali
|How to cite this article:|
Nagarajan K, Srinivasan TM, Rama Rao NH. Immediate Effect of Indian Music on Cardiac Autonomic Control And Anxiety: A Comparative Study. Heart India 2015;3:93-100
|How to cite this URL:|
Nagarajan K, Srinivasan TM, Rama Rao NH. Immediate Effect of Indian Music on Cardiac Autonomic Control And Anxiety: A Comparative Study. Heart India [serial online] 2015 [cited 2020 Jul 15];3:93-100. Available from: http://www.heartindia.net/text.asp?2015/3/4/93/172350
| Introduction|| |
Music powerfully modulates social, emotional processes, cognitive status, and mood, thus contributing to healing.  The Greeks, Hebrews, and Persians used music systematically as a therapy.  Music therapy can be used effectively as a preventive measure, and it can be used as a supplement to the main treatment after the onset of the pathological condition. The appropriate type of music, with specific tonal quality, played at a suitable time helps to drive out negative feelings such as dependency and loneliness. Music creates an atmosphere of harmony and well-being.  Musical compositions are complex blends of expressively organized sound consisting of five elements, viz., rhythm, melody, pitch, harmony, and interval. These five elements are vital when selecting music to invoke both psychological and physiological responses within the listener. 
Indian musicological analysis
Indian music therapy is about the correct intonation and precise use of the basic elements such as nada (sound), shruti (musical interval), swara (note), raga (melody) tala (beat), and laya (rhythm). The four elements noteworthy in this context are swara or note, Indian raga or melody, rasa or aesthetic mood, and thaat or mode.
Sa, ri, ga, ma, pa, dha, and ni are the seven notes or swaras of the Indian musical scale. Each of the notes or swaras either lowered or raised in pitch, are known as komal (flat note) or teevra (sharp note). Shadja (Sa) and Panchama (Pa) are two steady or natural notes having no distortion or displacement. Rishabha (ri), Gandhara (ga), Madhyama (ma), Dhaivata (dha), and Nishada (ni) are accepted as having two forms as stated above, namely, one high and one low. It is total of 12 notes. 
Rasa or aesthetic mood is comprehended when an emotion is awakened in such a manner that it has none of its cognitive tendencies, and it is experienced in an impersonal contemplative mood.  Raga is the sequence of selected notes (swaras) that lend an appropriate rasa or aesthetic mood in a selective combination. Depending on its tonal quality, a raga could induce or intensify joy or sorrow, excitement or peace, and it is this quality, which forms the foundation for therapeutic application.  Thaat or mode is a certain array of the seven notes with a change in shuddha (pure), komal (flat), and teevra (sharp). Every raga has a fixed number of komal (soft) or teevra (sharp) notes, from which the thaat can be identified.  The shringara rasa or aesthetic mood of love is able to bring out the beauty and harmony that is present in everything and every moment. It creates the frame of mind, which enables us to focus on generating a lovely ambience within oneself and with one's friends and family. 
The ragas are classified according to the combination of shuddha (natural), komal (flat), and teevra (sharp) notes or swaras used and consequently the particular rasas or moods they are able to produce. Ragas with shuddha or pure notes ri, ga, dha depict the aesthetic mood or the rasa of love; komal or flat ri, dha create the rasa of compassion and calmness; komal or flat ga, ni creates the rasa of courage or self-assurance within the listener.  Listening to Indian ragas, which depict the mood of love, compassion, peace, and courage, may be used for dissolving negative thoughts and thereby bringing balance in the mental and emotional states.  The aesthetic mood of calmness is the culmination of other rasas such as love, compassion, and courage and is transcendental in nature.  The consolidation and evocation of rasa, then, represent the function of all Indian fine arts, especially music and dance.  Many studies have suggested that the most common purpose of musical experiences is to persuade emotions: People use music to modify emotions, to let go emotions, to match their current emotion, to rejoice or pacify themselves, and to relieve stress and rejuvenate. 
It was reported that positive emotions are related to speeded-up recovery from cardiovascular reactivity generated by negative emotions for resilient individuals. Research has also shown that positive emotions may have beneficial physical and psychological health outcomes by serving a defensive role and thus, providing a useful remedy to the problems associated with negative emotions and illness. 
The Indian raga Bhupali, which belongs to Kalyan thaat, equivalent to the Lydian mode  of Western music was used in our study. This raga uses ri, dha teevra or sharp notes, which instill the shringara rasa or aesthetic mood of love within the listener.  This raga is sung in the evening. Listening to the right raga at the right time is said to smoothen the natural transitions and attune the body and mind to the circadian cycle.  Our proposal is that autonomic changes observed in other studies in response to listening to music are mainly elicited by changes in emotional and psychological states and these states can be favorably changed by the combination of notes or swaras used in the raga as mentioned above in the article.
The biological effects of Indian music, leading to its therapeutic efficacy are not entirely known. In this study, we aimed at further studying some biological correlate of listening to the particular Indian raga, which instills a positive aesthetic mood within the listener. Previous studies have demonstrated that the autonomic nervous system may serve as a way by which music can be effectively used for the therapeutic application. This is explored by the assessment of heart rate variability (HRV). Therefore, the objective of this study was to assess the effects of exposure to the Indian raga Bhupali on HRV with that of two control groups of pop music and no music or silence in a sample of healthy subjects. Secondarily, we correlated autonomic responses to musical stimuli with that of the state anxiety level before and after each music style. No previous studies have investigated the short-term effects of the Indian raga Bhupali and pop music on HRV. The understanding of physiological responses induced by music experience is a key to develop future therapies in order to prevent the development of cardiovascular disorders.
Heart rate variability and emotions
HRV is a measure of the continuous interplay between sympathetic and parasympathetic influences on the heart rate (HR) that yields information about cardiac autonomic flexibility and thereby represents the capacity for regulated emotional responding. 
In one of the studies, it was documented by McCraty that anger in a normal sample elicited an increase in the low frequency and low frequency (LF)/high frequency (HF) ratio components of HRV, suggesting disruption in sympathovagal discharge caused by increase in the sympathetic contribution. Appreciation, on the other hand, elicited an increase in the medium frequency component and a slight increase in the LF component, suggesting more parasympathetic than sympathetic activation during the positive emotion. 
The activation of the sympathetic branch of the autonomic nervous system (ANS) increases HR while the activation of the parasympathetic branch, primarily intervened by the vagus nerve, slackens it. Variation in the HR can be caused by a variety of factors including breathing, emotions, and various physical and behavioral changes. The HR changes in response to internal body rhythms, many of which reveal various homeostatic control systems. In general, high HRV represents a flexible ANS that is responsive to both internal and external stimuli and is associated with fast reactions and adaptability. Diminished HRV, on the other hand, represents a less transient, less flexible ANS that is less able to respond to stimuli change. It follows that HRV may provide a promising index of an athlete's ability to respond to both physical and emotional stress and thus, of the capacity to perform physically at maximal levels. 
We hypothesized that the participants who listened to Indian raga Bhupali would be influenced by the aesthetic mood of the song that depicts shringara rasa or love. This state of mind would bring about relaxation. Further, that it would increase cardiac parasympathetic activity, which is exclusively responsible for the HF peak of the HR power spectrum. This would also be correlated with lower scores of state anxiety. We also predicted that pop music which is much liked by teenagers may be exciting and cause an increase in cardiac sympathetic activity responsible for the LF peak of the HR power spectrum. The study also had another control condition of no music or silence which we predicted may not help to silence or relax the mind.
| Materials And Methods|| |
Twenty-eight undergraduate college students, both male and female, with age ranging from 18 years to 24 years (19.68 ± 2.57 years) were recruited for the study. They were all students of the Residential Yoga University. All of them were of normal health based on routine case history and clinical examination. All participants expressed their willingness to participate in the experiment, and the project was approved by the institution's ethics committee. The study protocol was explained to the subjects, and their signed consent was obtained.
Each subject was assessed in three sessions, into which they are randomly assigned. Two of them are musical sessions and one session was without music. One musical session was an intervention session with the Indian raga Bhupali, based on popular composition. The second - control session - was with pop music with steady beats. The third - control session was silence or "no music session." All the three sessions consisted of three states, i.e., "pre" (5 min), "during" (10 min), and "post" (5 min) for HRV. The allocation of participants to the three sessions was random using a standard random number table. The assessments were made on three different days for each recording, not necessarily on consecutive days but at the same time of the day (i.e., the self-as-control design). The design is presented schematically in [Figure 1].
|Figure 1: Schematic representation of study design - D1 indicates during1; D2 during 2|
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Baseline HRV was recorded for 5 min. Subsequently, HRV was recorded for 10 min while the individual was exposed to the Indian raga Bhupali and again it was recorded for 5 min post exposure to music.
We used two pieces of melody in the raga Bhupali. The songs are popular classical-based film music - a.Jyoti Kalash Jhalake played in the confluence of three instruments, the sitar (Sunil Das), flute (Rakesh Chaurasia), and santoor (Ulhas Bapat) and b.Pankh Hoto Uda Aatire flute rendition by Praveen Gorkhindi.
The term "pop" is originally derived from an abbreviation of "popular." It borrows elements from other preexisting musical styles, which include urban, dance, Latin, rock, and country.  In general, college students prefer them since it invokes the feeling of excitement.
We used Electro pop beat - a. "Can't Keep Me Away" by Chinchilla Music Production and b. K-391 - Sky City 2013 by K-391. Both the pieces of music use synthesizers and various electronic musical instruments.
HRV was recorded by using Biopac MP 100 (Biopac Systems Inc., 42 Aero Camino, Goleta, CA 93117, USA) and analyzed by Kubios HRV 2.00 software (Biosignal Analysis and Medical Imaging Group, University of Eastern Finland). The HRV power spectrum was obtained using Fast Fourier Transform (FFT) analysis. The energy in the HRV series in the following specific frequency bands studied viz., low frequency (LF) band (0.05-0.15 Hz) and high frequency (HF) band (0.15-1.50 Hz) and the LF/HF ratio. The low frequency and high frequency band values were expressed as normalized units. The following components of time domain HRV were analyzed: (i) Mean HR (average number of times your heart beats in one minute), (ii) RMSSD (root mean square of successive differences) and (iii) NN50 (the number of interval differences of successive NN intervals greater than 50 ms). Secondarily, we correlated autonomic responses to musical stimuli with the anxiety level before and after each music style and also for "silence" or "no music" session. The State and Trait Anxiety Inventory (STAI) was used to assess anxiety.  The STAI consists of 40 items divided into two components X1 and Y1, these two components assess state and trait anxiety respectively in both clinical and non clinical populations. We have used X1 component of STAI to assess state anxiety. Scores for both scales range between 20 (low anxiety) and 80 (high anxiety).  The perceived feeling was measured using the visual analog scale (VAS). The VAS consists of a horizontal 10-cm line with one end representing the maximum and the other end representing the minimum of the variable to be measured.  The right anchor of the scale was identified as "feeling very good" and the left anchor was labeled "feeling not good" as in [Figure 2]. Participants indicated their state of feeling by marking a point after the experimentation.
Data were analyzed using SPSS for Windows, Version 16.0. Chicago, SPSS Inc. Released 2007. There were separate repeated measures of analyses of variance (ANOVAs) for each of the assessments, with four within-subjects factors [i.e., states (before, during 1, during 2, and after) and sessions (raga, pop, and silence)]. Post hoc analysis was with Bonferroni adjustment, comparing after with before values.
| Results|| |
The group mean values ± standard deviation (SD) and the percentage change pre versus post for frequency domain measures of HRV spectrum for LF, HF, and LF/HF, and time domain measures of mean HR, RMSSD, and NN50 in three sessions (raga, pop, and silence) in pre, during, and post states are given in [Table 1] and [Table 2], respectively. [Figure 3] and [Figure 4] shows the trend of percentage change shown in frequency domain measures and time domain measures of HRV spectrum respectively, recorded post the Indian raga session and two control sessions of pop music and silence.
|Figure 3: The trend of percentage change shown in the frequency domain measures of heart rate variability spectrum recorded post the Indian raga session and two control sessions of pop music and silence|
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|Figure 4: The trend in arrows and percentage change shown in time domain measures of heart rate variability spectrum recorded post the Indian raga session and two control sessions of pop music and silence|
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|Table 1: Frequency domain measures for 3 sessions in 4 states for LF, HF, and LF/HF with a percentage change for (pre versus post)a |
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|Table 2: Time domain measures for 3 sessions in 4 states for mean HR, RMSSD, and NN50, and the percentage change (pre versus post)a |
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Analysis of variance
The significant changes in both frequency and time domain measures in thre sessions are given in [Table 3].
Post hoc analyses with bonferroni adjustment
Post hoc analyses with Bonferroni adjustment were performed and all comparisons were made with the respective "pre" states summarized in [Table 4].
|Table 4: Significant results of post hoc analysis where the arrows show the direction of changes |
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In summary, there was a significant decrease in LF (P < 0.01) and mean HR (P < 0.01) after the raga session compared to the preperiod. There was a significant increase in HF (P < 0.01), NN50 (P < 0.05), and RMSSD (P < 0.05) after the raga session compared to the preperiod. There was a significant decrease in HF (P < 0.05) and NN 50 (P < 0.05) during the pop session compared to the prestates. The anxiety level significantly (P < 0.001) decreased post the raga session as summarized in [Table 5]. There was a significant increase in state anxiety level (P < 0.01) after the pop Session. The subjective assessment of perceived feeling using the VAS comparing raga with pop and silence sessions showed a significant positive difference (P < 0.01) as summarized in [Table 6].
|Table 5: State Trait Anxiety (STAI) in conditions of Indian raga, pop music, and silencea |
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|Table 6: Scores on visual analog scale following raga, pop, and silencea |
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Psychological stress measures
The anxiety level before and after the sessions of raga, pop, and silence or no music was assessed using the STAI.
VAS - Visual analog scale
The perceived feeling was measured using VAS for all the participants following raga, pop, and Silence. Repeated measures of ANOVA were performed with one "within-subjects" factor, i.e., raga, pop, and silence sessions.
| Discussion|| |
The present study examined the changes in subjective and psychophysiological responses to the Indian raga Bhupali, pop music, and no music conditions. The perceived relaxation induced by Indian raga was shown in both frequency domain and time domain measures of HRV.
The LF (normalized units) component significantly decreased and correspondingly HF component significantly increased immediately after listening to the Indian raga Bhupali. This was indicative of reduced arousal and a shift in the autonomic balance toward parasympathetic dominance. There was a decrease in the LF/HF ratio, which was not statistically significant. The LF/HF ratio is correlated with sympathovagal balance.  The LF component of the HRV is mainly related to sympathetic activation when expressed in normalized units,  whereas afferent vagal activity is a major contributor to the HF component. Apart from this, there was a significant decrease in the HF component during pop music, indicative of an increase in cardiac sympathetic activity. 
In the time domain measures, there was a significant increase in RMSSD and NN50. These indices reflect short-term variation and are correlated with the HF power or the parasympathetic activity.  There was a significant decrease in the mean HR. As described above, most of the changes immediately after listening to Indian raga were indicative of reduced activity in the different subdivisions of sympathetic nervous system though some variables are regulated by several factors. The HR, for example, is regulated by twofold innervations (sympathetic and parasympathetic), as well as humoral factors. 
This makes the decrease in HR complex to interpret (i.e., it could be due to increased vagal tone or due to sympathetic withdrawal). This also applies to HRV components. On the contrary, there was a significant decrease in NN50 of the frequency domain measure during pop session, which reflects sympathetic activation.
Collectively, the results suggest that the immediate effect of listening to Indian raga Bhupali is associated with changes in the autonomic nervous system suggesting vagal control.
This was also correlated with significant reduction in the anxiety level assessed using the STAI and subjective feeling of the session. Cardiac vagal tone has been proposed as a stable biological marker for the ability to sustain attention and regulate emotion. 
Previous studies have demonstrated particular profiles of autonomic responses on different styles of music. This has prompted the need to explore the effects of Indian raga, which has the effect of instilling positive emotions within the listener before it can be proposed as an effective music therapy.
The factors which reflect an emotional and effective response to music are soothing and relaxing music, urban factors such as rhythm and percussion, sophisticated factors, which include classical music, an intense factor such as loudness, forceful and energetic music, and campestral factor comprising country and folk songs.  We were confident that this stimulus had a stress-reducing capacity independent of individual preferences because of the combination of the notes, the aesthetic mood it instills while listening, the slow tempo, and the popularity of the piece of music we used. The point to be noted here is that using researcher-selected music stimuli have been shown to have greater effects on stress reduction than music stimuli selected by the subjects themselves. 
In general, rock music is preferred by contemporary college students and heavy metal is mostly preferred by adolescent boys. Concerns have been raised regarding psychological, emotional, behavioral, and physical effects associated with this music preference.  Study taking self-report reasons for pop music preference revealed that characteristics such as the melody, mood, rhythm, and lyrics of a selection were the important reasons for preference.  But the results in one of the studies indicated that the dominant factor affecting emotional response was the music type (either relaxing or stimulating) and not preference.  In one of the studies, the stimulating music aroused feelings of vigor and tension more than the calming music while sedative music eased tension. Favorite music, regardless of music type, lowered subjective tension. Physiological responses (HR, respiration, and blood pressure) were greater during stimulating music than during calming music. Music preference did not, however, affect the physiological responses. 
Passive listening to music accelerates breathing rate and increases blood pressure, HR, and the LF: HF ratio (thus suggesting sympathetic activation) proportional to the tempo and perhaps to the complexity of the rhythm.  Slow tempo with soothing notes may have had helped in parasympathetic activation, which is shown in our study. Pop music with steady beats may have increased sympathetic activation.
Comparison with previous studies of music and heart rate variability
There was a differential influence of music-listening on autonomic activity; it was observed that music resulted in a faster autonomic recovery after stress compared to the control groups.  The results showed that acute exposure to classical baroque music reduced the sympathetic tone of the heart while excitatory heavy metal music decreased the variability of the HR.  The techno music with steady beats was associated with a significant increase in HR, systolic blood pressure, and significant changes in self-rated emotional states.  The effect of trophotropic (relaxing) music on HR and HRV was investigated. The results showed that relaxing music (Bach, Vivaldi, and Mozart) resulted in a significant reduction of HR. The significance of these results might be relevant for the use of music in coronary heart disease is also discussed.  Listening to soft music and inhaling Citrus bergamia essential oil (aroma therapy) was found to be an effective method of relaxation, as indicated by a shift of the autonomic balance toward parasympathetic activity in young healthy individuals.  In comparison, our results correlated with previous studies where the soothing effect of Indian raga showed similar effects as that of Vivaldi, Mozart, and Bach. Pop music with steady beats increased sympathetic activation.
| Conclusion|| |
The present study results suggested the importance of the aesthetic mood of music in altering autonomic responses and reducing the anxiety levels. This has also helped in recognizing the mechanism through which Indian music may affect the physiological change by instilling a particular aesthetic mood within the listener. The Indian raga Bhupali may be effectively used in cardiac regulation and may also facilitate recovery from poststress anxiety suggestive of applications in clinical settings. In general, knowledge of musical elements will help the participants to appreciate and willfully submit to the musical composition. In our study, the participants were from different ethnic groups and not all of them had musical training or the knowledge of the elements of Indian music. In spite of this factor, the musical stimulus has brought about positive changes. The study may be extended to various other Indian ragas in the above applied areas by identifying sensitive physiological variables.
Respiratory rate is also influenced by the autonomic nervous system but we did not measure the respiratory rate during the sessions. This accounted for a limitation in our study.
| Acknowledgements|| |
The authors gratefully acknowledge Dr. Hariprasad V R, Dr. Kashinath Metri and Dr Raghavendra Bhat for their guidance and Dr. Balram Pradhan for his help in Statistical Analysis.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]