The effects of listening to healing beat music on adults' recovery from exposure to stressful stimuli: A randomized controlled trial.

BACKGROUND: Musical auditory stimulation can affect the brain and autonomic nervous system, resulting in psychological and physical relaxation. In particular, listening to healing beat music with a tempo synchronized with an individual's heart rate can make a person feel comfortable. This study investigated whether healing beat music, utilized as a heartbeat-matched auditory stimulus, could be employed to improve patient recovery after exposure to stressful stimuli.
METHODS: This study was a randomized controlled trial and participants were adults above age of 20 who voluntarily participated. As outcome variables, stress index, BIS index, sympathetic nerve activity, and blood pressure were measured and compared at 5 min intervals.
RESULTS: Following the treatment, the stress index (F = 3.78, p < .001), BIS index (F = 5.61, p < .001), and systolic blood pressure (F = 3.14, p =.019) of the a healing beat music listening group (HBMG) were significantly lower than those of the control group (CG). More specifically, the stress index (P <.05) and the BIS index (P <.05) of the HBMG were lower than the indices of the preferred music listening group (PMG) and the CG at 30 min.
CONCLUSIONS: Listening to healing beat music with a tempo synchronized with the heart rates of the participants had the effect of lowering stress index and systolic pressure. Accordingly, healing beat music may be utilized as a treatment method to relieve stress in both clinical and daily life contexts.

Introduction

As stress is linked to myriad poor health outcomes, there is a growing interest in integrative medical treatments used to relieve excessively high stress. These treatments include complementary or alternative therapies and placing a greater emphasis on integrated care.

One alternative intervention showing potential promise is music therapy. This treatment modality directly impacts the brain without patients having to endure excessive or invasive intervention. This complementary, alternative therapy can be easily applied, and, furthermore, it has immediate therapeutic effects with only a few adverse effects, regardless of time and space parameters. As music therapy affects the hypothalamus area of the brain (via the auditory system) and the autonomic nervous system, it can improve psychological and physical relaxation and influence blood flow.

Recent studies have demonstrated that music-based interventions can positively influence cardiovascular and autonomic nervous systems as well as brainwaves. A regular or rhythmic beat can be synchronized with human rhythms, producing further therapeutic effects. However, studies conducted on stress interventions employing music therapy have mostly been limited to preferred choices of music or classical music, with differences in stress before and after the administration of experimental treatment primarily assessed.

Considering the literature, the present study examines the effects of listening to healing beat music with a tempo in sync with a person's heart rate on stress resilience and confirms its effectiveness. This study involved adults listening to therapeutic healing music, consisting of a distinct heartbeat-like tempo and rhythm, and assessing the music's effects on multiple physical and psychological stress-related outcomes. To assess the normative effects of this intervention on the relief and prevention of daily stress, healthy adults were chosen to participate in the study. All experiments were conducted under constant environmental conditions to minimize the impact of external variables on the reported outcomes. This study was further designed to identify any potentially continuous stress ameliorating effects of music therapy, rather than simply those following treatment.

Methods

Study design

This study utilized a randomized controlled design (Supplement).

Participants

The participants volunteered to participate in the study between April and August of 2017. All of the participants were over 20 years of age, able to communicate without assistance, had no history of hearing-related, physical, or psychological illnesses, and were not receiving medication for anxiety or sleep disorders. Furthermore, all of the participants provided written informed consent, and the study was approved by our Institutional Review Board.

Randomization and blinding

Sample sizes were obtained by inputting an alpha value, statistical power, and effect size into the G-power 3.1.7 program (Heinrich Heine University, Dusseldorf, Germany). To compare three groups, the effect size was calculated based on a previous study by inputting the number of groups, standard deviation, and mean score. This yielded an effect size of 0.34. The sample size was then calculated using the effect size 0.34, significance level 0.05, and statistical power 0.9. The total required sample size was determined to be 90. The present study included 102 participants, allowing for a 14% dropout rate. Accordingly, a healing beat music listening group (HBMG), a preferred music listening group (PMG), and a control group (CG) were each assigned 34 participants. One individual in the PMG refused to participate, three in the CG were excluded due to their taking medication, and one subject in the CG was unable to participate. Thus, 97 participants were involved in the study, comprising 34, 33, and 30 participants in the HBMG, PMG, and CG, respectively (Fig. 1).

Fig. 1

Flow diagram of the participants.

For group assignment and allocation concealment, a list of participants was compiled for each group, and a random number generator was used to assign each subject a value between one and three, corresponding to one of the three groups, the HBMG, PMG, or CG. Participants were not informed of the group in which they were assigned. The data collector applied headphones to three groups of the HBMG, PMG, or CG and played music (preferred music, healing Beat, and silence) to be single blinded.

Procedure

Laboratory preparations

A 22.82m laboratory with a comfortable indoor temperature maintained between 22 °C and 24 °C, a range previously determined to minimally activate the autonomic nervous system, was used for all tests. The laboratory had windows for ventilation, as well as a couch, table, and chairs for the participants’ comfort.

Stressors

A mental arithmetic task and white noise were used as the stress stimuli (stressors). White noise, in which non-patterned tones are distributed evenly across the audible range (20 to 20.000Hz), was played continuously to participants at 70dB through headphones (NWZ-WH505, Sony Corporation, Tokyo Japan) for 3 min, as in a previous study. The participants were then instructed to perform a mental arithmetic task wherein they would continuously subtract 17 from 6135 for 2 min. When an incorrect answer was given, the participants were instructed to restart the arithmetic task.

Experimental intervention

Healing beat music

The stimulus used here, termed “healing beat music” (Korea Patent No 10-2018-0147801), consisted of tones designed to match the rhythmicity of individuals’ heart rates. Listening to healing beat music involved playing participants a rhythmic beating auditory stimulus synchronized with their assessed average heart rate in beats per minute. This was within the normal heart rate beats per minute range of 60 to 100. The healing beat music consisted of repetitive G, C, D, G chords played in a time signature of 4/4. A keyboard and guitar ensemble consisting of 40 total sound sources were used to produce this music. After enduring stress, the healing beat music was played to each participant in the HBMG through headphones (Quiet Comfort15Ⓡ, Bose, Boston, MA, USA, 2016) for 40 min at 40 dB, a level approximately equal to the volume of proximal interpersonal dialogue.

The healing beat music group (HBMG)

The participants were exposed to the stress stimuli (described above), followed by the healing beat music intervention for 40 min.

The preferred music group (PMG)

The participants were exposed to the stress stimuli and then played music of their choice through headphones (Quiet Comfort15Ⓡ, Bose, Boston, MA, USA, 2016) at 40 dB for 40 min.

The control group (CG)

After exposure to the stress stimuli, the participants who did not hear the auditory stimulation with headphones were instructed to relax for 40 min.

Primary outcome measures

Stress index

The stress index was measured using the Canopy9 professional 4.0 device (IEMBIO, Gangwon-do, Korea), which continuously measures autonomic nervous system activity for 5 min. This assessment quantitatively assesses autonomic nervous system balance based on Heart Rate Variability (HRV). The numbers of the index range from 1 to 10, with higher numbers indicating greater levels of stress.

Bispectral index assessment

The BIS index is an objective measurement of ongoing levels of conscious sedation in a patient. This index measures patient sedation using a BIS monitor (Aspect Medical System, USA) and sensor (QUATRO sensor, Aspect Medical System Inc., USA). The US Food and Drug Administration approved BIS monitoring in 1996 for this purpose. BIS index values range from 0 to 100, with a score between 90 and 100 indicating a conscious patient with intact memory, a score between 65 and 85 indicating sedation, a score between 45 and 65 indicating general anesthesia with deep hypnosis and impaired memory function, and a score of less than 40 indicating cortical suppression and/or complete unresponsiveness.

To measure a subject's BIS index, the subject's forehead was sterilized with alcohol before attaching the device. After four electrodes were attached approximately 2,3 cm above the nose, skin resistance was measured, and light pressure was applied to lower resistance at any electrode indicating a high level.

Secondary outcome measures

Sympathetic nerve activity

Sympathetic nerve activity, as assessed here, was a quantitative value determined by HRV, measured by the range of low frequency (LF). This is equivalent to the sympathetic nerve index. Sympathetic nerve activity was continuously measured for 5 min using the Canopy9 professional 4.0 (IEMBIO, Gangwon-do, Korea), with a higher value indicating participant exposure to a stressor.

Blood pressure assessment

The participants’ systolic and diastolic blood pressures were assessed using an electronic HP Monitor manometer (M1106C, Phillips, USA). Participants were seated during the assessment, and blood pressure was measured on the upper arm by a trained assessor.

Data collection procedure

Data were collected between March and August of 2017 as per the following procedures:

The participants were recruited using the bulletin board of the university in D city by publicizing the research purpose and recruitment target. Potential candidates were contacted and selected after having their conditions and medication statuses verified.

Explanations of the experimental treatment, investigation methods, self-assessments, and self-withdrawal procedures were provided to all participants, and signed consent forms were obtained by IB and research assistants.

Microsoft Excel (Microsoft, Redmond, Wash) was used to randomly assign participants to one of the three groups: the experimental, placebo, or control group.

When participants first visited the laboratory, they were asked to sit in a comfortable position and rest for five minutes. As a pre-survey (T0), each participant's baseline stress index, sympathetic nerve activity, BIS index, and blood pressure were assessed.

Upon exposure to the stressors (Ts), each participant's baseline stress index, sympathetic nerve activity, BIS index, and blood pressure were measured.

Then, depending on the group a participant was assigned to, one of the three interventions—listening to healing beat music, listening to preferred music, or relaxing for 40 min—was employed.

All of the participants were assessed at multiple time points, 5  min intervals [T5, T10, T15, T20, T25, T30, T35, T40], using the following procedure: Post-survey assessments were carried out during experimental treatment, wherein a participant's heartbeat was measured every five minutes for 40 min, for a total of eight assessments.

All data were numerically codified for anonymity and analyzed upon collection.

Statistical analyses

The data were analyzed using SPSS Statistics for Windows, version 22.0 (SPSS Inc., Chicago, Ill., USA). General data characteristics were analyzed, including frequency, real numbers and percentages, and the homogeneity of the experimental, placebo, and control groups using X2-tests and ANOVA. Differences in the outcome variables among the three groups were analyzed using ANOVA and repeated measures ANOVA.

Results

The baseline characteristics

There were no significant differences among the three groups concerning general characteristic homogeneity or baseline dependent variables, indicating that the three groups were similar (Table 1).

Table 1

Homogeneity of the study group characteristics.

Characteristics /Variable	HBMG (n=34)	PMG (n=33)	CG (n=30)	F or X²	P
	Mean±SD or N(%)
Age (yrs)	20.03± 1.98	19.67± 1.85	20.50±2.30	1.312	.274
Height (cm)	164.38± 9.42	163.92± 7.45	167.70± 7.08	2.016	.139
Body weight (kg)	61.74±14.53	58.44±10.46	60.16±13.81	0.536	.587
Gender				2.874	.238
Male	9(26.5)	5(15.2)	10(33.3)
Female	25(73.5)	28(84.8)	20(66.7)
Alcohol consumption				2.451	.294
No	5(14.7)	3(9.1)	1(3.3)
Yes	29(85.3)	30(90.9)	29(96.7)
Smoking				3.712	.156
No	31(91.2)	31(93.9)	29(96.7)
Yes	3(8.8)	2(6.1)	1(3.3)
BIS index	93.12± 2.04	93.85± 2.45	93.33± 2.02	0.578	.563
Initial stress index	3.97± 2.60	4.55± 2.74	4.50± 2.54	0.491	.614
Initial LF activity	5.48± 1.49	5.50± 1.29	5.42± 1.72	0.290	.971
Initial SBP (mmHg)	116.00±11.72	114.09±10.55	115.33±10.01	0.598	.552
Initial DBP (mmHg)	70.17± 9.60	69.60± 9.18	68.70± 7.39	0.225	.799

CG, Control Group; DBP, Diastolic Blood Pressure; HBMG, Healing Beat Music Group; LF, Low Frequency; PMG, Preferred Music Group; SBP, Systolic Blood Pressure; SD, Standard Deviation.

Primary outcomes

Stress index scores increased upon exposure to the stressor, and there was a significant group-by-time interaction effect (F = 3.78, p < .001) identified by repeated measures analysis during experimental treatment. Thirty minutes into the experimental treatment, the stress indexes of the HBMG participants were significantly lower than those of the participants in the PMG or CG (p < .001) (Table 2). The BIS index scores showed a significant difference regarding group-by-time interaction (F = 5.61, p < .001), and there was a significant difference in the stability of the three groups according to time. The results of the post-analysis showed that the BIS indexes of the three groups were significantly different after 30 min of the experimental treatment. The HBMG especially showed significantly lower stress than the PMG or CG (p < .001) (Table 2).

Table 2

Comparisons of Stress index, BIS index, and LF activity among the HBMG, PMG, and CG.

Variable		HBMG (n = 34)	PMG (n = 33)	CG (n = 30)	F	p	F (p)*
		Mean ± SD
Stress index	T0	4.24 ± 2.40	4.55 ± 2.74	4.50 ± 2.54	0.142	.868	Time 13.36 (< .001) G*T 3.78 (< .001) Group 4.03 (.021)
	TS	6.15 ± 3.16	4.94 ± 2.83	5.73 ± 2.61	1.505	.227
	T05	5.85 ± 1.78	5.21 ± 2.74	5.57 ± 3.17	0.510	.602
	T10	4.68 ± 0.94	4.67 ± 2.43	5.27 ± 2.86	0.755	.473
	T15	4.79 ± 1.01	4.52 ± 2.74	4.97 ± 2.62	0.327	.722
	T20	4.09 ± 0.79	4.30 ± 2.56	4.93 ± 2.57	1.349	.265
	T25	3.62 ± 0.89	4.00 ± 2.38	4.73 ± 2.98	2.045	.135
	T30	2.44 ± 0.78a	4.06 ± 2.30b	5.17 ± 2.90b	13.084	< .001
	T35	2.38 ± 0.74a	4.03 ± 2.52b	5.00 ± 2.61b	12.682	< .001
	T40	1.91 ± 0.75a	3.94 ± 2.52b	4.33 ± 2.58b	12.540	< .001
BIS index	T0	93.12 ± 2.04	93.85 ± 2.45	93.33 ± 2.02	.983	.378	Time 73.49 (< .001) G*T 5.61 (< .001) Group 9.99 (< .001)
	TS	95.76 ± 2.30	95.33 ± 2.31	95.73 ± 2.32	.356	.702
	T05	90.09 ± 8.36	88.88 ± 9.04	92.40 ± 5.13	1.651	.197
	T10	86.65 ± 9.69	88.52 ± 8.96	90.53 ± 6.99	1.597	.208
	T15	84.38 ± 10.90	85.48 ± 10.22	87.87 ± 7.91	1.034	.360
	T20	78.68 ± 12.05a	82.03 ± 10.27a	86.47 ± 9.22b	4.285	.017
	T25	75.56 ± 11.86	81.45 ± 13.26	81.33 ± 18.48	1.754	.179
	T30	67.06 ± 10.78a	80.03 ± 14.33b	82.60 ± 14.46b	12.996	< .001
	T35	59.88 ± 9.62a	77.52 ± 15.90b	78.00 ± 16.98b	16.980	< .001
	T40	69.85 ± 13.90a	79.67 ± 15.70b	82.40 ± 14.08b	6.684	.002
LF activity	T0	5.48 ± 1.49	5.50 ± 1.29	5.42 ± 1.17	0.029	.971	Time 36.56 (< .001) G*T 1.38 (.149) Group 1.49 (.230)
	TS	5.97 ± 1.40	5.96 ± 1.17	5.87 ± 1.09	0.057	.945
	T05	5.74 ± 1.33	5.62 ± 1.27	5.37 ± 1.46	0.626	.537
	T10	4.92 ± 1.60	5.16 ± 1.32	4.94 ± 1.74	0.240	.787
	T15	4.80 ± 1.66	5.37 ± 1.41	5.13 ± 1.41	1.191	.308
	T20	4.72 ± 1.63	5.37 ± 1.19	5.11 ± 1.40	1.765	.177
	T25	4.54 ± 1.45a	5.47 ± 1.25b	5.22 ± 1.57b	3.751	.027
	T30	4.41 ± 1.42a	5.34 ± 1.23b	5.21 ± 1.57b	4.296	.016
	T35	4.82 ± 1.12	5.36 ± 1.34	5.18 ± 1.33	1.584	.211
	T40	5.18 ± 1.37	5.47 ± 1.25	5.74 ± 2.43	0.845	.433

Means for each group with a different superscript (a, b) indicate a significant difference (Bonferroni's test; p < .05); *Repeated Measures ANOVA; G*T: Group*Time.

CG, Control Group; HBMG, Healing Beat Music Group; LF, Low Frequency; PMG, Preferred Music Group; SD, Standard Deviation; T0, Baseline; TS, Exposure to Stressors; T05, 5 min into Experimental Treatment; T10, 10 min into Experimental Treatment; T15, 15 min into Experimental Treatment; T20, 20 min into Experimental Treatment; T25, 25 min into Experimental Treatment; T30, 30 min into Experimental Treatment; T35, 35 min into Experimental Treatment; T40, 40 min into Experimental Treatment.

Secondary outcomes

There was no statistically significant difference in the sympathetic nervous system activity among the three groups. The post hoc analysis showed differences at 25 min (p = .027) and 30 min into experimental treatment (p = .016) (Table 2). The systolic blood pressures of the three groups significantly reduced over time; systolic blood pressure was significantly lower at 30 min (p = .020) and 35 min (p = .005) into the treatment (Table 3).

Table 3

Comparisons of systolic blood pressure(SBP) and diastolic blood pressure(DBP) among the HBMG, PMG, and CG.

Variable		HBMG (n = 34)	PMG (n = 33)	CG (n = 30)	F	p	F (p)*
		Mean ± SD
SBP (mmHg)	T0	116.97 ± 11.72	114.09 ± 10.55	115.33 ± 10.77	0.598	.552	Time 80.85 (< .001) G*T 3.14 (.019) Group 0.38 (.682)
	TS	119.47 ± 15.74	115.39 ± 11.08	116.70 ± 12.55	0.818	.444
	T05	114.38 ± 15.61	110.48 ± 10.76	113.03 ± 11.08	0.802	.451
	T10	110.76 ± 12.71	108.58 ± 9.96	110.43 ± 9.89	0.381	.684
	T15	108.26 ± 10.72	107.36 ± 9.60	108.93 ± 9.83	0.193	.825
	T20	107.47 ± 9.48	103.73 ± 15.49	108.50 ± 9.57	1.434	.244
	T25	106.68 ± 8.70	104.52 ± 9.53	106.57 ± 9.07	0.586	.559
	T30	100.03 ± 5.29a	103.70 ± 8.64a	105.20 ± 8.21b	4.103	.020
	T35	98.38 ± 4.35a	102.97 ± 8.50b	104.37 ± 9.14b	5.611	.005
	T40	101.76 ± 3.00	103.15 ± 8.74	104.23 ± 9.74	0.842	.434
DBP (mmHg)	T0	70.18 ± 9.60	69.61 ± 9.18	68.70 ± 7.39	0.225	.799	Time 46.59 (< .001) G*T 0.51 (.594) Group 0.47 (.622)
	TS	68.71 ± 10.68	67.81 ± 7.89	68.13 ± 7.64	0.086	.918
	T05	66.82 ± 9.84	64.52 ± 7.95	65.47 ± 7.06	0.637	.531
	T10	66.15 ± 9.66	64.06 ± 8.05	64.83 ± 6.99	0.534	.588
	T15	65.47 ± 9.15	63.24 ± 7.67	64.07 ± 7.32	0.645	.527
	T20	65.50 ± 9.38	62.55 ± 7.50	63.40 ± 6.90	1.196	.307
	T25	64.06 ± 9.17	62.03 ± 8.08	62.90 ± 7.06	0.517	.598
	T30	63.41 ± 9.46	61.39 ± 8.07	61.63 ± 6.82	0.596	.553
	T35	62.88 ± 9.50	61.55 ± 7.21	61.97 ± 6.94	0.244	.784
	T40	62.76 ± 9.79	62.03 ± 8.91	61.00 ± 6.97	0.292	.747

Means for each group with a different superscript (a, b) indicate a significant difference (Bonferroni's test; p < .05); *Repeated Measures ANOVA; G*T: Group*Time.

CG, Control Group; DBP, Diastolic Blood Pressure; HBMG, Healing Beat Music Group; LF, Low Frequency; PMG, Preferred Music Group; SBP, Systolic Blood Pressure; SD, Standard Deviation T0, Baseline; TS, Exposure to Stressors; T05, 5 min into Experimental Treatment; T10, 10 min into Experimental Treatment; T15, 15 min into Experimental Treatment; T20, 20 min into Experimental Treatment; T25, 25 min into Experimental Treatment; T30, 30 min into Experimental Treatment; T35, 35 min into Experimental Treatment; T40, 40 min into Experimental Treatment.

Discussion

Given study results, listening to healing beat music has been demonstrated to effectively reduce the stress index scores of healthy participants. The results reported here are similar to those reported in the literature.

In this study, the participants were exposed to a level of stress comparable to that experienced in daily life. Ward and Fricke argued that noise can impair work performance and that when concurrently asked to perform arithmetic tasks, individuals experience sympathetic nervous system activation and parasympathetic inactivation, and self-report elevated stress levels. Therefore, the use of an auditory stress stimulus (70 dB white noise) and an arithmetic task serves as relevant stressors that may equate to individuals’ experiences in daily life. To verify that these stimuli were indeed stressful and impacted participants’ physiology, we measured the participants’ stress index scores, BIS index scores, sympathetic nervous system activity, and blood pressure before, during, and after exposure to the stressors. The results indicated that exposure to these stressors triggered a stress response in the participants.

To determine whether the healing beat music treatment successfully reduced participants’ stress reactivity, we measured stress index scores, which reflect autonomic nervous reactivity to stress. After exposure to stress, the index scores of the three groups increased. Twenty minutes into the experimental treatment, the HBMG's stress index decreased to pre-stressor levels or lower and continued to decrease at 25, 30, 35, and 40 min. Meanwhile, the CG's stress index levels did not recover to pre-stressor levels (or lower) until after 40 min of treatment. Further analyses revealed that after 30 min of the experimental treatment, the stress index scores in the HBMG decreased significantly compared to those in the PMG and CG. Music therapy has been successfully employed for the treatment of stress and anxiety in coronary heart disease patients, and Cervellin and Lippi reported that heartbeat-based stimuli can be utilized for stress reduction. However, the anti-stress effects of these auditory interventions were typically measured via assessments before and after stress exposure, not continuously, as in this study. Measuring changes over time can allow for a more effective assessment of the clinical utility of music intervention and identification of the precise moment that participants recover from stress. Music therapy is especially effective when healing beat music is listened to rather than preferred music. The continuous nature of stress assessment used in this study is, therefore, a particular strength of this research.

The BIS index was used to determine the levels of participants’ alertness and sedation. During experimental treatment, the BIS index scores among all three groups were found to decrease in a temporally-specific phenomenon: no significant differences were identified at 5, 10, 15, or 25 min among the three groups, whereas significant differences were found at 30, 35, and 40 min. Post-hoc analyses revealed that the HBMG's BIS index scores decreased more significantly than those of the PMG or CG after 30, 35, and 40 min of the experimental treatment. The sympathetic nervous system activity in the experimental group was found to be affected shortly after exposure to the stressor at 10 min, with levels subsequently decreasing for 30 min and then increasing slightly after 35 min of the experimental treatment. However, after 40 min, as the experiment was nearing its conclusion, the activity levels in the placebo and control groups had almost entirely recovered or were higher than earlier values, while those in the experimental group had decreased. This study shows that, the result can be confirmed that the sympathetic nervous system through LF (low frequency) among the autonomic nervous system effects. In particular, it is related to the research results that music therapy lowers the sympathetic nervous system and activates the parasympathetic nervous system. This result demonstrates that healing beat music intervention can have an impact on the autonomic nervous system.

Finally, systolic and diastolic blood pressure was measured to determine the impact of the healing beat music intervention on physiological parameters relevant to stress reactivity. Systolic blood pressures in the HBMG and PMG decreased significantly after 30 and 35 min. Healing beat music or preferred music may, then, help to lower blood pressure and have a sedating effect on the body, emotional and mental constitution, and sympathetic nervous system activity. More specifically, our data demonstrate that systolic blood pressure levels began to decrease after 5 min of the experimental treatment, with a significant decrease versus controls at 30 and 35 min, and a period of stability achieved at 40 min. These findings result from the experimental design of our study which allowed changes in blood pressure to be identified over time. Unlike systolic blood pressure, diastolic blood pressure among all three groups generally decreased after 5 to 40 min of experimental treatment with no significant differences among the groups. Unlike previous studies, where music therapy is effective in lowering blood pressure in individuals with hypertension, this study is an important study to confirm how effectively the normotension group stabilizes in stressful situations. In particular, the application of various music in the normotension group is effective on systolic blood pressure, but is consistent with the results of studies in which the control of diastolic blood pressure is limited. Thus, supporting the literature, the music therapy employed in this study successfully regulated blood pressure after stress exposure.

Most of the previous music-based therapy studies exploring stress, autonomic nervous system activity, and blood pressure regulation have focused on diseased populations or have only examined levels before and after an intervention. Furthermore, no studies have investigated the autonomic nervous system or blood pressure levels after the application of an auditory stimulus with a beat synchronized with participants’ normal heart rates. Therefore, the results of this study expand on previous research and may serve as a basis for further clinical application of this stress reduction method. Moreover, as the present study identifies the effects of this intervention on stress recovery over time, the results are of particular relevance to efficient nursing practice and the determination of the temporal dynamics of stress recovery.

One limitation of this study is that despite the participants not being informed of the groups to which they were assigned, the experimental treatment was not completely blinded to the participants due to the characteristics of the treatment.

In summary, based on the results presented in this study, listening to healing beat music is an effective method for alleviating stress levels measured by stress index, BIS index, and systolic blood pressure. Thus, healing beat music therapy may be utilized as a clinical tool for the relief of stress triggered by exposure to a stressor or simply daily life. Furthermore, this intervention may be recommended to patients suffering from other conditions, particularly those with acute or chronic diseases.

CRediT authorship contribution statement

Ik-Lyul Bae: Conceptualization, Methodology, Formal analysis, Investigation, Data curation, Writing – original draft, Funding acquisition. Yeon-Suk Kim: Conceptualization, Formal analysis, Data curation, Writing – original draft, Writing – review & editing. Myung-Haeng Hur: Conceptualization, Formal analysis, Investigation, Writing – original draft, Writing – review & editing.

Conflict of interests

The authors declare no conflict of interests.