Author(s): HAUSER, R., BESSON, C., GREMEAUX, V., DEGACHE, F., Institution: CHUV: CENTRE HOSPITALIER UNIVERSITAIRE VAUDOIS, Country: SWITZERLAND, Abstract-ID: 2236

INTRODUCTION:
Heart Rate Variability (HRV) exhibits a strong association with the autonomic nervous system (ANS) activity. In recent years, HRV has been used as an effective and reliable method of measurement to assess different fatigue status and recovery in athletes [1]. Low-frequency sound vibration (LFV) has been proved to increase the reactivity of cardiac vagal regulation and physical relaxation [2]. LFV is perceived through the auditory pathway and through skin mechanoreceptors. This study analyzed a unique pattern of LFV (RubesaSounds), which are highly structured and designed to create a neural saturation to enhance recovery. The aim of this study was to assess the acute effects of LFV on vagally-related HRV variables in regularly active male.
METHODS:
27 participants went through 2 different randomly chosen sessions in the exact same conditions. A conventional relaxation session (CRS) with no sounds nor vibrations and another LFV session. The LFV session consisted of 50 minutes of sounds (40-80Hz) inducing whole body vibrations. The duration of each session was 50 minutes. R-R intervals were collected in a supine position during the entire experience and lasted until 30 minutes post-session. HRV data was acquired using a heart rate monitor (Polar H10) and analyzed with Kubios Premium software.
RESULTS:
A significant intervention effect (P=0.003) for HR between pre-session (63±8.5) and 30 minutes post-session (59.2±8.2) was observed in the LFV group only. Another significant intervention effect (p=0.035) was found in the ratio of low and high frequency powers in relation to heart rate ((LF+HF)/HR) which increased between pre-session (81.7±80.8) and 30 minutes post-session (135.1±130.3) in the LFV group only. No significant time effect was observed in RMSSD and LnRMSSD between pre- and post-30 in both groups. The recovery HRVs (between during and post-30) were significant in LFV for LnRMSSD (p=0.015), (LF+HF)/HR (p=0.007) and RMSSD (p=0.02) and non-significant in all variables for the CRS session.
CONCLUSION:
This study was able to describe evidence of increased vagal tone post-intervention in LFV vs conventional relaxation session. A major finding of the study was a 1.5-fold increase in recovery speed compared to a conventional recovery session. Positively influencing vagal tone with LFV could offer a new perspective in sports-related recovery technologies. Our results are congruent with previous studies on the effect of vibrations on the ANS.

1 – Bestwick-Stevenson T, Toone R, Neupert E, Edwards K, Kluzek S. Assessment of Fatigue and Recovery in Sport: Narrative Review. Int J Sports Med. 2022 Dec;43(14):1151-1162.
2 - Bartel L, Mosabbir A. Possible Mechanisms for the Effects of Sound Vibration on Human Health. Healthcare (Basel). 2021 May 18;9(5):597.