The Effect of Low Frequency Sound on Heart Rate Variability and Subjective Perception: A Randomized Crossover Study

Abstract

Background: Vibroacoustic therapy (VAT) uses low-frequency sound, often combined with listening to music, for therapeutic purposes. However, the impact of low-frequency vibration (LFV) on physiological functions and subjective perception is relatively unknown. Methods: We conducted a randomized cross-over study with the aim of comparing the effect of constant LFV of 40 Hz, its amplitude modulation, and the placebo condition on heart rate variability (HRV), stress perception (measured by visual analogue scales for stress) and mood (measured by UWIST Mood Adjective Check List). Results: Research experiments with various interventions (constant LFV with sound of nature (river in forest), amplitude modulation of the same LFV with sounds of nature and sounds of nature without LFV) were realised involving 24 participants. It was found there was an effect on HRV, stress perception and mood after the interventions. However, there were only seldomly experienced, and mostly nonsignificant, differences between the intervention conditions, so the effects may be attributed to factors other than LFV. Conclusions: Large scale experimental studies are needed to verify the preliminary findings and to explore various coinciding factors that may have influenced the results of this study, e.g., type of autonomic nervous system. We propose that the effect of LFV exposure may differ when combined with listening to music, and this hypothesis should be investigated in future studies.

Nature Sounds for Stress Recovery and Healthy Eating: A Lab Experiment Differentiating Water and Bird Sound

“…Nevertheless, there was a trend toward better negative affect recovery in the bird and water sounds compared to the control sound. Also in literature, nuances exist within the subjective reports: bird song improved positive but not negative mood (Benfield et al, 2014), while river sounds in another study stimulated recovery in self-reported stress and HRV but not in emotions (Vilímek et al, 2022).…”

Effect of low frequency sound vibration on acute stress response in university students—Pilot randomized controlled trial

“…Amplitude modulations were first studied by Wigram (1997) and further explored in various experiments by additional researchers (Vilímek et al, 2019(Vilímek et al, , 2022; including authors of this study). Sequenced modulations of LFS make it possible to minimize some secondary complications in frequent vibroacoustic sessions described as overstimulation (Wigram, 1996).…”

“…Although university counseling centers offer essential support services, many students would benefit from developing further preventive non-pharmacological strategies, especially those that could offer immediate relief of stress symptoms and help cope with situational demands, thereby contributing to health promotion in educational institutions. Based on results of empirical observations ( Skille, 1989 ), as well as pilot studies ( Delmastro et al, 2018 ; Vilímek et al, 2022 ), a potential method for coping with acute stress response may be found in vibroacoustic therapy.…”

“…We call this type of low frequency sound (LFS) “sequenced modulation”—the LFS vibration is driven by the rhythmic structure of musical composition, ebbing and flowing with the amplitude of the music, and the parameters of LFS reflect the characteristics of music (see a description of recording called “Elements” in Table 1 ). The sound recordings developed for Vibrobed are based on the research ( Wigram, 1997 ; Vilímek et al, 2022 ) of the effect of amplitude modulation of different durations (in seconds), sine sweep up and down in the frequency range 30–80 Hz and various modulations of low-frequency waves in combination with sound and music stimuli.…”

Effects of Vibroacoustic Stimulation on Psychological, Physiological and Cognitive Stress

“…Consequently, the field remains unestablished. Preliminary research infers the intervention can relieve stress [28] though assessment of this is scarce [29][30][31][32]. To the authors knowledge, four studies to date specifically compare the effect of vibroacoustic interventions on stress using biosignal measurements.…”