Acute effects of passive listening to Indian musical scale on blood pressure and heart rate variability among healthy young individuals – a randomized controlled trial

Background Listening to music is entertaining but also has different health benefits. Music medicine involves passive listening to music, while music therapy involves active music making. Indian music is broadly classified into Hindustani and Carnatic music, each having their own system of musical scales (ragas). Scientific studies of Indian music as an intervention is meagre. Current study determines the effect of passive listening to one melodic scale of Indian music on cardiovascular electrophysiological parameters.

Methods After informed consent, healthy individuals aged 18 – 30 years, of either gender were recruited and randomly divided into 2 groups (n=34 each). Group A was exposed to passive listening to the music intervention [Hindustani melodic scale elaboration (Bhimpalas raga alaap)], while group B received no intervention except for few natural sounds (played once in every 2 minutes). Blood pressure (BP, systolic – SBP; diastolic – DBP) and Electrocardiogram in lead II were recorded with each condition lasting for 10 minutes (pre, during, post). Heart rate variability (HRV) analysis was done. Data was analysed using SPSS 20.0 version and p<0.05 was considered significant.

Results Passive listening to the musical scale employed had a unique effect. In group A, the SBP did not change during the intervention but increased insignificantly after the intervention was stopped (P=0.054). The DBP increased in both the groups during intervention and was significant among subjects in group A (P=0.009), with an increase of 1.676 mm Hg (P=0.012) from pre-during and 1.824 mm Hg (P=0.026) from pre-post intervention. On HRV analysis mean NN interval increased and HR reduced in both the groups, but was significant only in group B (P=0.041 and 0.025 respectively). In group A, most of HRV parameters reduced during music intervention, and tended to return towards baseline after intervention, but was statistically significant for Total Power (P=0.031) and Low Frequency (P=0.013) change; while in group B a consistent significant rise in parasympathetic indicators [SDNN, RMSSD, Total power and HF (ms²)] over 30 minutes was observed.

Conclusion Unique cardiovascular effects were recorded on passive listening to a particular Indian music melodic scale, raga Bhimpalas, wherein, a mild arousal response, was observed. This could be due to attention being paid to the melodic scale as it was an unfamiliar tune or due to certain notes of this melodic scale, that particularly caused an arousal or excitation response. In contrast, the control group had only relaxation response. Exploring electrophysiological effects of different genres, melodic scales and its properties after familiarizing with the music may be illustrative.