The Effect of Different Acoustic Conditions on 6-Minute Walk Test Performance and Recovery

Study Design: Randomized Cross-Over Study Objective: This study aims to compare the acute effects of three different auditory conditions (metronome, binaural beats, and silent control) on 6-Minute Walk Test (6MWT) performance, post-exercise recovery physiology, and perceived exertion in healthy young adults. Background: Auditory-motor coupling mechanisms suggest that rhythmic auditory stimuli can lower the excitation threshold of motor neurons, thereby enhancing walking efficiency. Rhythmic stimuli such as metronomes are known to improve walking speed and coordination. Binaural beats are an auditory stimulus type generated by presenting two tones of slightly different frequencies to each ear, triggering cortical neural entrainment. It has been reported that listening to binaural beats at theta frequency following exercise increases parasympathetic activation and accelerates recovery. This study aims to examine these two auditory stimuli in comparison with a control condition in healthy young adults. Participants: Healthy young adults aged 18-35 who can walk independently and have no cardiovascular, pulmonary, neurological, or musculoskeletal conditions. Minimum sample size will be calculated using G\*Power following a pilot study, with a 20% dropout margin added. Randomization: All participants will be exposed to all three conditions on separate days. The order of application will be determined by computer-based simple randomization (randomizer.org). Six possible sequence combinations will be used to balance order effects. A washout period of at least 24 hours will be applied between sessions. Interventions: Metronome Condition: Each participant's natural walking cadence will be measured, and the metronome tempo will be set at 110% of this baseline value. Binaural Beats Condition: A carrier frequency of 120 Hz will be delivered to the right ear and 100 Hz to the left ear, generating a 20 Hz binaural beat in the Beta frequency band. Participants will listen for 6 minutes at rest immediately before the walking test. Control Condition: No auditory stimulus will be applied. The 6MWT will be conducted in all conditions along a 30-meter flat corridor in accordance with ATS/ERS standards. Measurement Time Points: Pre-test, immediately post-test, and at the 1st, 3rd, and 5th minutes of the recovery period. Outcome Measures: Primary: Total distance covered during 6MWT (meters), walking cadence (steps/min) Secondary: Heart rate, blood pressure, peripheral oxygen saturation (SpO₂), perceived dyspnea, general fatigue, and quadriceps femoris muscle fatigue assessed via the Modified Borg Scale Statistical Analysis: One-Way Repeated Measures ANOVA for walking distance and cadence; Two-Way Repeated Measures ANOVA (condition × time) for physiological parameters; Friedman test for Borg scale data; Bonferroni-corrected post-hoc tests where significant differences are found. Significance level set at p\<0.05. Study Duration: April - June 2026 (3 months)

This study employs a randomized cross-over design in which each participant will undergo all three auditory conditions (binaural beats, metronome, and silent control) on separate days. To minimize potential carryover effects from a preceding condition, a washout period of at least 24 hours will be maintained between sessions. The order of condition administration will be determined by computer-assisted simple randomization (https://www.randomizer.org/) to balance potential order, fatigue, and learning effects. Participants will be randomly assigned to one of six possible sequences: Sequence 1: Control - Metronome - Binaural Sequence 2: Control - Binaural - Metronome Sequence 3: Metronome - Control - Binaural Sequence 4: Metronome - Binaural - Control Sequence 5: Binaural - Control - Metronome Sequence 6: Binaural - Metronome - Control Interventions 1. Metronome Condition (Rhythmic Auditory Stimulation) To objectively determine each participant's natural walking cadence, a 30-second pre-walk assessment will be conducted before the test session. The participant will be asked to walk at their preferred comfortable pace, and the number of steps taken over 30 seconds will be counted and recorded by the researcher. This value will be multiplied by two to calculate the 1-minute baseline walking cadence (steps/minute) (Chase et al., 2023). The metronome tempo accompanying the test will then be standardized at 110% of the participant's baseline cadence (i.e., 10% above their natural rhythm), in accordance with the protocol established by Yu et al. (2015). The target metronome rhythm (beats per minute, BPM) will be calculated by multiplying the baseline cadence by a coefficient of 1.10. The metronome stimulus will be delivered continuously throughout the 6MWT via open-ear headphones. 2. Binaural Beats Condition Binaural beats stimulation involves the simultaneous delivery of two pure sound waves of different frequencies to each ear, with the brain perceiving the mathematical difference between these two frequencies as a third, internally generated beat. In this protocol, a carrier frequency of 120 Hz will be delivered to the right ear and 100 Hz to the left ear, generating a binaural difference of 20 Hz corresponding to the Beta frequency band (\~20 Hz), which is associated with cognitive alertness and motor focus. Carrier frequencies in the 100-120 Hz range were selected as they are physiologically safe and well-tolerated by the human ear (Chaieb et al., 2015). The binaural audio file was created using Audacity (version 3.7.5.0) software, with the two frequency channels carefully separated to prevent mixing. Pink noise was added to the background of the binaural stimulus to enhance listening comfort and mask environmental sounds without physically occluding the ear canal. Since the literature indicates that binaural stimulation requires a neurological adaptation period to fully demonstrate its targeted cortical effects (Gao et al., 2014), parti Покажи пълното описание...

Inclusion Criteria: * Aged between 18 and 35, * Able to walk unaided (without the use of a walking aid), * Participants who agree to take part in the study on a voluntary basis and sign the informed consent form Exclusion Criteria: * A history of myocardial infarction or unstable angina within the last month, * Acute illness or pain during the test that would prevent walking, * A lower limb injury or surgery within the last 3 months, * Resting systolic blood pressure \>180 mmHg or diastolic blood pressure \>100 mmHg, * Resting heart rate exceeding 120 beats per minute, * Those with cardiovascular or pulmonary conditions that may limit exercise, * Those with neurological conditions (balance disorders, stroke, epilepsy, etc.), * Those with musculoskeletal problems (lower limb fracture, severe arthritis, acute injury, etc.), * Those with an acute infection, fever or severe fatigue that could prevent walking during the test, * Those with a body mass index of 35 or above (obesity), * Those with a history of active vertigo, Meniere's disease or vestibular system disorders, * Participants with a diagnosed hearing problem