Differential effects of sound interventions tuned to 432 Hz or 443 Hz on cardiovascular parameters in cancer patients: A randomized cross-over trial

Abstract

Background
This study investigated whether a sound intervention tuned to 432 Hertz (Hz) yields differential effects on cardiovascular parameters and psychological outcomes compared to 443 Hz, which is the concert pitch in German professional orchestras.

Methods
Using a randomized cross-over design, patients with cancer were recruited to receive both a 15-minute sound intervention with a body monochord tuned to 432 Hz or 443 Hz. Before (pre) and after (post) intervention, cardiovascular parameters were measured using the VascAssist2.0. In addition, visual analogue scales (VAS) for emotional well-being, anxiety, stress, pain and sadness were also assessed pre and post intervention.

Results
43 patients (8 male, 35 female) with a median age of 61 years (range 35–86) were included. Both interventions led to a significant reduction in heart rate with a more pronounced effect for 432 Hz (median reduction − 3 bpm (432 Hz) vs median reduction − 1 bpm (443 Hz), p = 0.04). While heart rate variability was increased exclusively by 432 Hz (median increase + 3 ms, p = 0.01), both vascular resistance (median reduction − 5%, p = 0.008) and stiffness (median reduction %, p = 0.04) were significantly reduced by 432 Hz, which was not observed at 443 Hz. Nevertheless, these effects were not significantly different compared to 443 Hz. On the other hand, 432 Hz led to a reduced pulse wave velocity (median reduction − 0.5 m/s, p < 0.001), which was also significantly different compared to 443 Hz (p < 0.001). Improvement in VAS was observed for both groups, with significant increases in emotional well-being and reduction in fatigue, anxiety and stress for both intervention timepoints, although the majority showed no increased VAS scores even before the intervention (median values 0 for anxiety and stress).

Conclusion
Sound interventions tuned to 432 Hz or 443 Hz exert both positive effects in cancer patients. While psychological outcomes are improved by both interventions, 432 Hz leads to a more pronounced but not significantly different effect to 443 Hz on objective cardiovascular parameters, which reflect deeper relaxation.

Full text

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Differential effects of sound interventions tuned to
432 Hz or 443 Hz on cardiovascular parameters in
cancer patients: A randomized cross-over trial
Anna Hohneck
Heidelberg University
Ánxelo Maia Rodríguez
Heidelberg University
Simone Weingärtner
Heidelberg University
Kirsten Merx
Heidelberg University
Felicitas Sarodnick
Heidelberg University
Fritjof von Gagern
Musikalische Akademie Mannheim e.V
Athanasios Mavratzas
University Medical Centre Mannheim, Heidelberg University
Iris Burkholder
University of Applied Sciences of the Saarland
Gerhard Schumacher
inmediQ GmbH
Wolf-Karsten Hofmann
Heidelberg University
Ralf-Dieter Hofheinz
Heidelberg University
Research Article
Keywords: sound intervention, tuning, cardiovascular parameters, concert pitch
Posted Date: April 29th, 2024

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DOI: https://doi.org/10.21203/rs.3.rs-4144501/v1
License:   This work is licensed under a Creative Commons Attribution 4.0 International License. 
Read Full License
Additional Declarations: No competing interests reported.

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Abstract
Background
This study investigated whether a sound intervention tuned to 432 Hertz (Hz) yields differential effects on
cardiovascular parameters and psychological outcomes compared to 443 Hz, which is the concert pitch
in German professional orchestras.
Methods
Using a randomized cross-over design, patients with cancer were recruited to receive both a 15-minute
sound intervention with a body monochord tuned to 432 Hz or 443 Hz. Before (
pre
) and after (
post
)
intervention, cardiovascular parameters were measured using the VascAssist2.0. In addition, visual
analogue scales (VAS) for emotional well-being, anxiety, stress, pain and sadness were also assessed
pre
and
post
intervention.
Results
43 patients (8 male, 35 female) with a median age of 61 years (range 35–86) were included. Both
interventions led to a signicant reduction in heart rate with a more pronounced effect for 432 Hz
(median reduction − 3 bpm (432 Hz) vs median reduction − 1 bpm (443 Hz), p = 0.04). While heart rate
variability was increased exclusively by 432 Hz (median increase + 3 ms, p = 0.01), both vascular
resistance (median reduction − 5%, p = 0.008) and stiffness (median reduction %, p = 0.04) were
signicantly reduced by 432 Hz, which was not observed at 443 Hz. Nevertheless, these effects were not
signicantly different compared to 443 Hz. On the other hand, 432 Hz led to a reduced pulse wave
velocity (median reduction − 0.5 m/s, p < 0.001), which was also signicantly different compared to 443
Hz (p < 0.001). Improvement in VAS was observed for both groups, with signicant increases in emotional
well-being and reduction in fatigue, anxiety and stress for both intervention timepoints, although the
majority showed no increased VAS scores even before the intervention (median values 0 for anxiety and
stress).
Conclusion
Sound interventions tuned to 432 Hz or 443 Hz exert both positive effects in cancer patients. While
psychological outcomes are improved by both interventions, 432 Hz leads to a more pronounced but not
signicantly different effect to 443 Hz on objective cardiovascular parameters, which reect deeper
relaxation.
INTRODUCTION

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Various scientic and popular science sources indicate that music based on the concert pitch 432 Hertz
(Hz) could have possible positive effects on body and mind (1, 2). Most of the music we listen to, be it
classical or popular music, is based on the standard concert pitch, which was set at a1 = 440 Hz at the
1939 International Conference in London (3). In German and Austrian symphony orchestras, however, a1
= 443 Hz is usually preferred. While
Hertz
is the physical unit for frequency that indicates the absolute
number of oscillations per second, different tone systems and tunings can be compared using the
logarithmic unit
cent
(4). The interval between the frequencies 443 Hz and 432 Hz corresponds to a cent
value of 43.53. In comparison, the cent value of a semitone (minor second) in an equal temperament (as
the predominant tuning system of Western music) corresponds to 100 cents, so that the difference in
pitch between the tunings examined here is not recognizable by an average listener (5). The scientist and
founder of acoustics, Joseph Saveur, and other advocates argued for a musical basis in which the note
c1 (“middle C”) is at 256 Hz, which corresponds to the concert pitch of a1 = 432 Hz (6). This theory is
based on the principle that doubling the frequency leads to an octave increase in tone. One oscillation per
second (i.e., 1 Hz) corresponds to the tone C6. Since the hearing range for the human ear is age
dependent between 16 Hz and approx. 19000 Hz, we can hear tones from C2 onwards according to this
doubling series (C6 = 1 Hz, C5 = 2 Hz, C4 = 4 Hz, C3 = 8 Hz, C2 = 16 Hz, C1 = 32 Hz, C = 64 Hz, c = 128 Hz,
c1 = 256 Hz, ...), whereby the pleasant hearing range lies within the one-line (or fourth) octave (6).
Otologists and neurologists use tuning forks that are tuned to c = 128 Hz or c1 = 256 Hz, as the organ of
Corti (the actual sense of hearing in the inner ear), vibrates at c = 128 Hz (7).
Against this historical and musicological background, the assumption emerged that 432 Hz could be a
more physiological tuning and could therefore possibly have benecial effects. However, there is little
data to scientically support this hypothesis. The results of previous studies suggest that 432 Hz music
leads to a greater reduction in heart rate and blood pressure compared to standard pitch (8, 9), while
divergent results were found with regard to stress reduction, measured as State-Trait Anxiety Inventory or
perceived stress scales (9, 10). In the studies described, the sound intervention was performed with
melodic music tuned to 432 Hz which was played through headphones, while music therapists often use
sound bodies such as body monochords, that are played live during the intervention. In anthroposophical
music therapy, in addition to the conventional tuning of 440 Hz, the lower tuning of 432 Hz is frequently
used, although there is no scientic evidence (11).
The present study sought to assess the differential effects of sound interventions with a body
monochord tuned to 432 Hz or 443 Hz on cardiovascular parameters and psychological outcomes in
cancer patients.
METHODS
Study design and setting

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This randomized cross-over study was performed at the University Medical Centre Mannheim, University
of Heidelberg, Germany. It was designed as a head-to-head comparison of a sound intervention tuned to
432 Hz or 443 Hz. Recruitment started in June 2023 and ended in October 2023. Patients were not
followed up.
The study was conducted according to the principles of the declaration of Helsinki and was approved by
the local ethical committee, Medical Ethics Commission II, Faculty of Medicine Mannheim, University of
Heidelberg, Germany (2019-763N). Data protection was in accordance with the EU Data Protection
Directive.
Material and Methods
Study population
Forty-ve individuals > 18 years were included and gave written informed consent. Exclusion criteria
comprised serious hearing impairment, acute coronary syndrome or stroke within four weeks before study
participation, planned bypass surgery, dependence on pacemaker, cardiac arrhythmia (e. g., atrial
brillation, sick-sinus-syndrome, sinoatrial/ atrioventricular block), uncontrolled hypertension or severely
low blood pressure (< 90/50 mmHg) and breast cancer with bilateral axillary dissection.
Baseline characteristics
Baseline demographic characteristics (age, gender, weight, height, etc.) were collected from all study
participants, as well as information on existing medication and physical activity. In addition, participants
were asked if they were married and had children. Preferred music genre (multiple answers possible) was
assessed and it was questioned whether there is a hearing loss.
In addition, the Spielberger State-Trait Anxiety Inventory (STAI) (12), which is a psychometric test
consisting of 40 self-report items on a four-point Likert scale, and the European Organization for
Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire (QLQ-C30) (13) were assessed
at baseline. The STAI measures two types of anxiety – state anxiety and trait anxiety. Higher scores are
positively correlated with higher levels of anxiety. The QLQ-C30 is composed of 30 questions, comprising
15 subscales on three domains (global health status, functional scales, and symptom scales), with a
score ranging from 0 to 100 points for all subscales. A higher score in global health status or functional
scales represents a higher quality of life or better level of functioning. However, in the symptom
subscales, a higher score represents a higher level of symptoms or problems.
Sound intervention
All patients received both a 15-minute sound intervention with a body monochord tuned to a concert pitch
of 432 Hz or 443 Hz as part of a cross-over design. Interventions were performed in lying position after a
10-minute resting period. In order to rule out a systematic bias, the sequence of intervention was

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randomized. The two interventions took place within four weeks with at least a one-week blanking period
between the two interventions. The sound intervention was performed with the body monochord called
“Heaven and Earth” (http://klangkoerper.de/himmel-und-erde.html) (14). This instrument consists of a
semi-open resonance body with 29 strings (24 of those in C1sharp, 2 in C2sharp, 2 C3sharp, and 1 in
G3sharp) and is an established method in everyday clinical practice for music therapy (15, 16). The
monochord was placed on the chest during the intervention to ensure optimal transmission of the
vibrations. The instrument was played for 15 minutes by one of the investigators (AMR) in all patients.
Cardiovascular parameters
Cardiovascular parameters were assessed non-invasively using the VascAssist2.0 device (inmediQ
GmbH, Butzbach, Germany) after a 10-minute resting phase before (
pre
) and after (
post
) the intervention
and evaluated both for the total population and separately according to the intervention type (432 Hz vs
443 Hz).
The VascAssist2.0 is an oscillometric device that evaluates vascular properties non-invasively using
model-based pulse wave analysis. In addition to vital parameters (heart rate, brachial blood pressure),
pulse wave velocity (PWV), as a direct measure of arterial stiffness, and vascular indices (resistance,
stiffness), can be determined. Vascular age as a combined variable can be determined from these
vascular indices and the chronological age (17). Beyond that, augmentation index (Aix; also a marker for
arterial stiffness and determinant of central hemodynamics) and left ventricular ejection time (LVET,
indicator of systolic length) are also provided. Moreover, the root mean square of successive differences
between normal heartbeats (RMSSD) as heart rate variability (HRV) metric and stress indicator is
captured (18).
Psychological outcomes and personal assessment
Visual analogue scales (VAS) for emotional well-being, anxiety, stress, pain and sadness were assessed
before (
pre
) and after (
post
) the intervention. The VAS indicates a continuum ranging from 0 to 100,
where 0 represents the minimal and 100 the maximal extent. Moreover, after completing the two
interventions, the study participants were asked whether they had noticed a difference between the
sessions and which session they preferred.
Statistical analysis
Quantitative characteristics were evaluated using statistical parameters (N, arithmetic mean, standard
deviation, median, minimum and maximum) and qualitative characteristics were evaluated in the form of
frequency tables.
Cardiovascular parameters were measured before and after sound intervention (432 Hz or 443 Hz) and
evaluated descriptively both for the total population and per measurement time. In addition, the
differences to the baseline value were calculated and also analyzed descriptively, using the Wilcoxon
signed-rank test. The results were visualized with the help of grouped boxplots per parameter and

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measurement time and waterfall plots to display intraindividual differences before and after the
intervention.
Psychological outcomes were evaluated in the same way as cardiovascular parameters. In addition,
scatter plots of the measurements before and after the intervention were created grouped according to
the type of intervention.
All statistical analyses were performed with SAS 9.4. (SAS Institute Inc., North Carolina). Statistical
signicance was assumed at p < 0.05. The comparison of the two interventions is of exploratory nature.
RESULTS
A total of 45 patients were included in the study, whereby data from 43 patients were included in the nal
analysis (as two patients did not attend the second visit).
Baseline characteristics.
Baseline characteristics are shown in Table1.

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Table 1
Baseline characteristics
All patients
(N=43) 432 Hz – 443 Hz
(n=22) 443 Hz – 432 Hz
(n=21)
Sex, female (%) 35 (81) 16 (73) 19 (91)
Age, years 61 (35–86) 59 (35–86) 62 (37–80)
BMI (kg/m2)24 (17–38) 24 (17–37) 25 (19–38)
Married, yes (%) 23 (54) 12 (55) 11 (52)
Children, yes (%) 35 (81) 17 (77) 18 (86)
Regular physical activity
(%) 16 (37) 9 (41) 7 (33)
Hearing loss (%) 0 (0) - -
Preferred music genre (%)
(multiple responses
possible)
  
 Pop 22 (51) 12 (55) 10 (48)
 Rock 19 (44) 8 (36) 11 (52)
 Jazz 14 (33) 4 (18) 10 (48)
 Classical music 22 (51) 10 (46) 12 (57)
 Hits 11 (26) 7 (32) 4 (19)
 Hip Hop 2 (4.7) 1 (4.5) 1 (4.8)
 Others 13 (20) 8 (36) 5 (24)
QLQ-C30, median (range)
Global health status
67 (0–100) 67 (0–100) 67 (25–88)
Functional scales
  
 physical 73 (33–100) 73 (33–100) 73 (53–100)
 role 67 (0–100) 67 (0–100) 67 (0–100)
 cognitive 67 (17–100) 67 (17–100) 67 (33–100)
Data are presented as median (range) or numbers (frequencies).
BMI, body mass index; QLQ-C30, European Organisation for Research and Treatment of Cancer
(EORTC) Quality of Life Questionnaire (QLQ) composed of 30 questions; STAI, state trait anxiety
inventory

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All patients
(N=43) 432 Hz – 443 Hz
(n=22) 443 Hz – 432 Hz
(n=21)
 emotional 58 (17–100) 58 (17–100) 67 (17–100)
 social 67 (0–100) 67 (0–100) 67 (0–100)
Symptom scales
  
 fatigue 44 (0–100) 44 (0–100) 33 (11–89)
 pain 33 (0–83) 33 (0–83) 33 (0–83)
 nausea/ vomiting 0 (0–100) 0 (0–50) 0 (0–100)
Dyspnoea 33 (0–100) 33 (0–100) 33 (0–100)
Insomnia 50 (0–100) 67 (0–100) 33 (0–100)
Appetite loss 0 (0–100) 0 (0–67) 0 (0–100)
Constipation 0 (0–100) 0 (0–100) 0 (0–100)
Diarrhoea 0 (0–100) 0 (0–100) 0 (0–100)
Financial diculties 0 (0–100) 0 (0–100) 0 (0–100)
STAI, median (range) 44 (27–60) 48 (28–55) 43 (27–60)
Data are presented as median (range) or numbers (frequencies).
BMI, body mass index; QLQ-C30, European Organisation for Research and Treatment of Cancer
(EORTC) Quality of Life Questionnaire (QLQ) composed of 30 questions; STAI, state trait anxiety
inventory
A total of 8 patients were male (19%) and 35 patients (81%) were female. The median age was 61 years
(range, 35–86 years). 23 patients (54%) were married and 35 patients (81%) reported having children.
Regular physical activity was practiced by 16 study participants (37%).
Most common preferred music genres were pop (22 pts, 51%) and classical music (22 pts, 51%), followed
by rock (19 pts, 44%) and jazz (14 pts, 33%).
Median values for global health status, assessed using the QLQ-C30, were 66.7 points (0–100), with
median values of 58 to 73 observed for the functional scales and symptom scales ranging from a
median of 0 to 50. Median STAI scores, to reect anxiety levels, were 44 (27–60), and thus slightly above
the average for the German population (19).
Cardiovascular parameters.
Cardiovascular parameters were assessed using the VascAssist before (pre) and after (post) the sound
intervention (Table2).

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Table 2
Cardiovascular parameters
432 Hz (n=43) 443 Hz (n=43) p-value (Wilcoxon signed-rank test)
Heart rate (bpm)
pre 71 (51–94) 69 (47–109) 0.59
post 67 (50–90) 68 (51–100) 0.32
Difference post - pre -3 (-15–4) -1 (-12–9) 0.04
p-value < 0.001 0.01 
Brachial systolic BP (mmHg)
pre 127 (103–166) 125 (97–162) 0.98
post 120 (92–158) 123 (95–158) 0.46
Difference post - pre -4 (-25–10) -3 (-23–5) 0.48
p-value < 0.001 < 0.001 
Brachial diastolic BP (mmHg)
pre 71 (52–92) 70 (48–91) 0.69
post 66 (49–89) 68 (44–91) 0.12
Difference post - pre -3 (-23–9) 0 (-15–25) 0.08
p-value 0.001 0.37 
RMSSD (ms)
pre 21 (7–192) 24 (6–175) 0.52
post 27 (9–163) 25 (6–173) 0.21
Difference post - pre 3 (-29–42) 1 (-48–31) 0.17
p-value 0.01 0.40 
Resistance (%)   
pre 63 (15–114) 56 (14–124) 0.96
post 54 (15–120) 55 (21–124) 0.28
Data are presented as median (range).
Aix@75, augmentation index standardized to a heart rate of 75 bpm (beats per minute); BP, blood
pressure; LVET, left ventricular ejection time; PWV, pulse wave velocity; RMSSD, root mean square of
successive difference.

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432 Hz (n=43) 443 Hz (n=43) p-value (Wilcoxon signed-rank test)
Heart rate (bpm)
Difference post - pre -5 (-38–18) -3 (-21–37) 0.18
p-value 0.008 0.29 
Stiffness (%)   
pre 60 (25–101) 58 (21–95) 0.52
post 49 (15–91) 59 (15–95) 0.04
Difference post - pre -5 (-28–23) -2 (-29–24) 0.49
p-value 0.04 0.21 
Aortic systolic BP (mmHg)
pre 106 (87–153) 109 (83–155) 0.86
post 105 (81–149) 110 (80–149) 0.55
Difference post - pre -4 (-22–6) -3 (-25–7) 0.65
p-value < 0.001 0.002 
Aortic diastolic BP (mmHg)
pre 72 (54–94) 72 (50–93) 0.91
post 66 (52–91) 70 (46–92) 0.09
Difference post - pre -3 (-22–9) -1 (-14–12) 0.07
p-value < 0.001 0.10 
Aix@75 (%)   
pre 16 (-10–84) 16 (-16–92) 0.52
post 15 (-8–92) 16 (-14–43) 0.92
Difference post - pre -0.8 (-20–9) 0.4 (-10–6) 0.64
p-value 0.68 0.85 
Aortic PWV (m/s)   
pre 9 (6–15) 8 (4–18) 0.003
Data are presented as median (range).
Aix@75, augmentation index standardized to a heart rate of 75 bpm (beats per minute); BP, blood
pressure; LVET, left ventricular ejection time; PWV, pulse wave velocity; RMSSD, root mean square of
successive difference.

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432 Hz (n=43) 443 Hz (n=43) p-value (Wilcoxon signed-rank test)
Heart rate (bpm)
post 8 (6–16) 8 (4–19) 0.29
Difference post - pre -0.5 (-5–7) 0 (-15–11) < 0.001
p-value < 0.001 0.70 
LVET (ms)   
pre 270 (207–335) 267 (199–344) 0.99
post 272 (227–350) 271 (193–322) 0.49
Difference post - pre 6 (-32–62) 4 (-30–62) 0.19
p-value < 0.001 0.06 
Vascular age   
pre 61 (28–89) 60 (33–94) 0.77
post 57 (25–92) 56 (31–95) 0.25
Difference post - pre -3 (-16–12) -1 (-8–17) 0.11
p-value 0.002 0.20 
Data are presented as median (range).
Aix@75, augmentation index standardized to a heart rate of 75 bpm (beats per minute); BP, blood
pressure; LVET, left ventricular ejection time; PWV, pulse wave velocity; RMSSD, root mean square of
successive difference.
Vitals
Both interventions led to a signicant reduction in heart rate (432 Hz p < 0.001; 443 Hz p = 0.01), with a
more pronounced effect for 432 Hz (median reduction − 3 bpm (432 Hz) vs median reduction − 1 bpm
(443 Hz), p = 0.04) (Fig.1a). Systolic blood pressure was also reduced by both interventions (p < 0.001),
while diastolic blood pressure did not change. HRV, on the other hand, measured as RMSSD (ms) was
increased exclusively by 432 Hz (median increase + 3 ms, p = 0.01; 432 Hz vs 443: p = 0.17) (Fig.1b).
Vascular indices
The 432 Hz intervention exerted effects on vascular indices, which were not observed at 443 Hz. Both
resistance (median reduction − 5%, p = 0.008; 432 Hz vs 443 Hz: p = 0.18) and stiffness (median reduction
%, p = 0.04; 432 Hz vs 443 Hz: p = 0.49) were signicantly reduced by 432 Hz, with a median decrease of 3

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years in vascular age (pre median 61 years (28–89) vs post median 57 years (25–92), p = 0.002; 432 Hz
vs 443 Hz: p = 0.11) (Fig.2).
Central hemodynamics
Effects on aortic blood pressure after the interventions were also detected. While both interventions led to
a reduction in systolic aortic blood pressure (432 Hz median reduction − 4 mmHg p < 0.001; 443 Hz
median reduction − 3 mmHg, p = 0.002; 432 Hz vs 443 Hz: p = 0.65), changes in diastolic aortic blood
pressure were only observed for 432 Hz (median reduction − 3 mmHg, p < 0.001), with a trend towards a
statistical difference compared to 443 Hz (p = 0.07). Aix remained unaffected. PWV was signicantly
reduced by 432 Hz (median reduction − 0.5 m/s, p < 0.001), which was also signicantly different
compared to 443 Hz (p < 0.001). However, it should be noted that the PWV in the 432 Hz group was
signicantly higher at baseline than in the 443 Hz group (PWV (m/s) 432 Hz median 9 (6–15) vs 443 Hz
median 8 (4–18), p = 0.003). LVET, as indicator of systolic length, was extended by both interventions
(432 Hz median increase + 6 ms, p < 0.001, 443 Hz median increase + 4 ms, p = 0.06), but failed to reach
statistical signicance for 443 Hz.
Psychological outcomes.
An improvement in psychological outcomes was observed in almost all study participants for both sound
interventions. This was particularly evident in an increase in emotional well-being (p < 0.001 for both
interventions). In addition, both interventions led to a reduction in fatigue, with a more pronounced effect
for 432 Hz (432 Hz p = 0.005; 443 Hz p = 0.01). Furthermore, an improvement in anxiety and stress was
also achieved in a large number of study participants (VAS anxiety 432 Hz p = 0.008, 443 Hz p < 0.001;
VAS stress p < 0.001 for both interventions), although the majority showed no increased VAS scores even
before the intervention (median values 0 for anxiety and stress). No statistical difference was found
between the effects of the two groups (Table3).

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Table 3
Psychological outcomes
432 Hz (n=43) 443 Hz (n=43) p-value (Wilcoxon signed-rank test)
VAS Emotional well-being
pre 69 (20–100) 71 (26–100) 0.83
post 78 (35–100) 75 (15–100) 0.64
Difference post - pre 6 (0–50) 3 (-37–31) 0.55
p-value < 0.001 < 0.001 
VAS Anxiety
pre 0 (0–76) 0 (0–75) 0.22
post 0 (0–6) 0 (0–60) 0.006
Difference post - pre 0 (-76–0) 0 (-75–0) 0.64
p-value 0.008 < 0.001 
VAS Stress
pre 0 (0–79) 0 (0–85) 0.66
post 0 (0–77) 0 (0–100) 0.99
Difference post - pre 0 (-47–0) 0 (-61–15) 0.42
p-value < 0.001 < 0.001 
VAS Fatigue
pre 13 (0–100) 28 (0–100) 0.16
post 0 (0–98) 2 (0–73) 0.07
Difference post - pre 0 (-84–18) 0 (-92–45) 0.97
p-value 0.005 0.01 
Data are presented as median (range).
STAI: state trait anxiety inventory; VAS: visual analogue scale
Personal assessment.
Twenty-eight patients (65%) reported having noticed a difference between the two interventions. 24
patients (56%) preferred the 432 Hz sound intervention while six patients (14%) appreciated the 443 Hz
sound intervention. Almost a third of patients (13 patients, 30%) stated that they liked both interventions
equally.

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DISCUSSION
There are only a few studies to date that investigate the effect of 432 Hz music, four of which compare
432 Hz with the international standard pitch of 440 Hz. The present study compared 432 Hz with 443 Hz,
which is the concert pitch in German professional orchestras. We chose 443 Hz to maximize the pitch
difference between the two frequencies. This pitch difference, which would be roughly equivalent to a
"quarter tone", is not noticeable to the average listener. Individuals with absolute perception (“absolute
pitch” or so-called absolute listeners) may experience diculties with 432 Hz music, as they cannot
reliably assign the tones they hear to a pitch. Absolute pitch is the ability to perceive pitch class and to
mentally categorize sounds according to this perceived pitch class (20). It could therefore be that 432 Hz
music has less of an effect on absolute listeners. The incidence of absolute pitch is given as 1:10.000,
whereby professional musicians are signicantly more likely to be absolute listeners (21). This supports
the hypothesis that absolute pitch is not an "innate gift", but a memory performance that can be achieved
through regular training (22). It might therefore be interesting to investigate whether sound interventions
in general and 432 Hz in particular have the same benecial effects in professional musicians. A study
from 2022 revealed that music tuned to 432 Hz resulted in higher perceived arousal, assessed by
personal rating (23). In this context, it would have been interesting to also explore objective measures.
One advantage of our study is that both personal ratings (VAS) and objective measures (cardiovascular
parameters) were assessed. While both interventions led to an improvement in psychological outcomes
(with no relevant difference), benecial effects on cardiovascular parameters were observed, which were
more pronounced at 432 Hz than at 443 Hz. For example, a greater reduction in heart rate and blood
pressure was observed at 432 Hz, which is in line with data from Calamassi et al. (8, 9). In addition, heart
rate variability, which has prognostic implications in patients with cancer, was increased exclusively by
432 Hz (24, 25). The best-established parameter for vascular stiffness is pulse wave velocity (PWV). PWV
indicates the propagation velocity at which the blood pressure pulse propagates through the circulatory
system (26). PWV is an important diagnostic marker for the assessment of vascular stiffness and is used
as a predictor for cardiovascular events (27). The vascular resistance and the arterial wall properties
largely determine the speed of the PWV. Both vascular resistance and stiffness were signicantly reduced
by 432 Hz, which was also reected in a decrease in PWV. This is congruent with results from earlier
studies by our group (28, 29) and further studies that investigated the effects of music on arterial
stiffness (30, 31). However, it should be noted that the PWV in the 432 Hz group was signicantly higher
at baseline than in the 443 Hz group.
At rst glance, one might speculate that patients allocated to the 432 Hz group tended to be sicker and
therefore concluded that they beneted more from the sound intervention. However, the choice of the
cross-over design argues against this potential bias. In addition, a decrease in vascular age as a
combined variable could also only be observed by 432 Hz. Vascular age is often used in cardiology to
communicate cardiovascular risk because of its emotional character (32). On the other hand, it breaks
down the results of the present study to a single number: a 432 Hz intervention reduced vascular age by a
median of 3 years! Furthermore, effects on central hemodynamics could be demonstrated. While 432 Hz
reduced both systolic and diastolic aortic blood pressure, for 443 Hz only a reduction in systolic aortic

Page 16/22
blood pressure was observed. The diastolic blood pressure indicates how much pressure the heart exerts
on the walls of the arteries in between beats and can therefore be used as marker of vascular function.
For this reason, diastolic blood pressure may be more important than systolic blood pressure when
studying the relaxing effects of music, and appears consistent in view of our results. Left ventricular
ejection time, which indicates the length of the systole, was extended by both interventions,
physiologically according to the reduction in heart rate. In addition to objectively measurable
cardiovascular parameters, psychological outcomes were also recorded in this study using VAS. Both
interventions were able to improve psychological outcomes, which was particularly evident in an increase
in emotional well-being. This has also been described in a systematic review (33). In addition, both
interventions led to a reduction in fatigue, with a more pronounced effect for 432 Hz. These results are
also consistent with previous studies in which music interventions (both prerecorded music and
participating in live music) could relieve cancer-related fatigue (34). Indeed, only short-term effects are
documented within this trial and studies with more frequent interventions are warranted to assess long-
term impact. Furthermore, a relief of anxiety and stress was also achieved in a large number of study
participants, although the majority showed no increased VAS scores even before the intervention. This
suggests either that the patients are receiving appropriate care and that psychological problems are also
adequately addressed during therapy, or that only patients with correspondingly low scores participated
in the study. Interestingly, other 432 Hz studies carried out to date also found no relevant difference in
terms of subjective stress reduction (8–10), while there was a signicant improvement in sleep scores
(10) and lower salivary cortisol levels (35). The effects of 432 Hz music do not appear to be perceivable
for the majority of patients, but several objective results obtained from different studies indicate an effect
on the cardiovascular system. This is consistent with the personal assessment of our study participants,
about two thirds of whom stated that they had noticed a difference and slightly more than half preferred
the 432 Hz intervention. Our study thus builds on the existing data and corroborates and expands the
previous ndings. It should be mentioned that our study population of 43 participants is the largest
compared to the existing studies. In addition, other cardiovascular parameters were recorded in
comparison to the standard vital parameters. An overview of previous studies compared to the current
study investigating the effects of 432 Hz music compared to 440/443 Hz can be found in the
Supplemental Table in the appendix.
Strengths and Limitations
The present study compared sound interventions tuned to 432 Hz and 443 Hz, the latter representing the
concert pitch in German professional orchestras. Whether the benecial effects on cardiovascular
parameters and psychological outcomes are actually attributable to the specic tuning of 432 Hz or
whether lower tunings are generally perceived as more pleasant cannot be answered with certainty on the
basis of the available data. Further studies should be performed to address this question, comparing for
instance 432 Hz music with an even lower tuning (e.g., 415 Hz, which is often used for baroque music).
Individuals with absolute perception („absolute listeners“) may experience diculties with 432 Hz music,
as they cannot reliably assign the tones they hear to a pitch. It is therefore unclear whether a sound

Page 17/22
intervention tuned to 432 Hz also exerts benecial effects on absolute listeners. Since no relevant
difference was found in the improvement of subjective parameters, a strength of the study is to combine
objective measures such as cardiovascular parameters with psychological outcomes to obtain a
comprehensive assessment. In addition, music played live via a body monochord was used. A
monochord compared to recorded music offers the advantage of a more vivid mixture of overtones,
which could play a special role in mode of action of 432 Hz music (“oscillation ratio”).
CONCLUSION
This study compared the differential effects of sound interventions tuned to 432 Hz or 443 Hz on
cardiovascular parameters and psychological outcomes in cancer patients. While both interventions
improved psychological outcomes, a greater inuence on cardiovascular parameters was observed with
432 Hz, but not signicantly different compared to 443 Hz. To what extent the positive effects are
actually attributable to the specic tuning of 432 Hz or whether lower tunings are generally perceived as
more pleasant cannot be answered with certainty on the basis of the available data. The present study
conrms and corroborates previous results that 432 Hz music exerts benecial effects, in particular on
cardiovascular parameters, whose increase is associated with an increased stress level.
Declarations
a) Ethics approval and consent to participate
The study was conducted according to the principles of the declaration of Helsinki and was approved by
the local ethical committee, Medical Ethics Commission II, Faculty of Medicine Mannheim, University of
Heidelberg, Germany (2019-763N). Written informed consent was obtained from all study participants.
b) Consent for publication
Not applicable.
c) Availability of data and materials
The data that support the ndings of this study will be made available from the corresponding author
upon reasonable request.
d) Competing interests
The authors declare that they have no known competing nancial interests or personal relationships that
could have appeared to inuence the work reported in this paper.
e) Funding

Page 18/22
This research received no specic grant from any funding agency in the public, commercial, or not-for-
prot sectors.
f) Authors' contributions
R.-D.H. and A.H. came up with the idea for the study. The music-based interventions were carried out by
A.M.R. with supervision by the music therapist F.S.. S.W., K.M. and A.M. identied suitable patients and
informed them about participating in the study. The musicological part of the manuscript was written
with the help of F.v.G.. Statistical analysis was carried out by the statistician I.B.. G.S. provided essential
scientic input concerning pulse wave derived cardiovascular parameters. W.-K.H. reviewed the
manuscript draft, which was prepared by A.H. and R.-D.H.. All authors read and approved the nal version
of the manuscript.
g) Acknowledgements
The authors would like to thank all participants for taking part in the study.
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Figures

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Figure 1
Vitals
Grouped boxplots for both 432 Hz (red) and 443 Hz (blue) intervention and waterfall plots displaying
intraindividual difference before (pre) and after (post) the intervention for a) HR (heart rate) and b)
RMSSD (root mean square of successive differences) as HRV (heart rate variability) measure. While both
interventions led to a HR reduction (with a more pronounced effect for 432 Hz), HRV was increased
exclusively by 432 Hz.

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Figure 2
Vascular age
Grouped boxplots for both 432 Hz (red) and 443 Hz (blue) intervention before (pre) and after (post) the
intervention. While 432 Hz signicantly reduced vascular age, there was no change for 443 Hz.
Supplementary Files
This is a list of supplementary les associated with this preprint. Click to download.
SupplementalTable432Hz.docx