Long-term Binaural Sounds and Heart Rate Variability

Intervention Participants will be randomly allocated to one of five conditions: (1) control (no sound exposure), (2) bansuri audio with binaural beats, (3) bansuri audio without binaural beats, (4) Aio (Maori puoro and moteatea) audio with binaural beats, or (5) Aio audio without binaural beats. Bansuri audio: The bansuri audio consists of instrumental recordings performed on the bansuri, a traditional Indian bamboo flute. The audio features slow, melodic phrases with sustained tones and minimal rhythmic complexity, designed to create a calm and steady auditory environment. No lyrics or spoken words are included. Aio (Maori puoro and moteatea) audio: The Aio audio consists of recordings incorporating Maori puoro (traditional Maori instruments) and moteatea (traditional chant). The puoro include instruments such as taonga puoro that produce natural, breath-based and resonant sounds. The moteatea component includes unaccompanied or minimally accompanied vocal chant delivered in te reo Maori. The intervention consists of listening to a 20-minute audio track via earbuds. Binaural beats are auditory stimuli created by presenting slightly different frequencies to each ear, resulting in a perceived third tone. Audio tracks are provided by the research team and delivered via participants’ smartphones. Who delivers it and their relevant expertise The intervention is delivered by the research team, who are experienced in cardiovascular physiology, heart rate variability measurement, and culturally grounded health research. The team also has expertise in the development and use of binaural audio tracks, including Maori soundscapes (puoro and moteatea), and in the use of wearable physiological monitoring devices (e.g., Oura Ring, Polar H10). How it is delivered The intervention is delivered individually and remotely. Participants listen to the assigned audio track on their own smartphone using personal earbuds. No in-person supervision is required after initial setup. How often and for how long Long-term exposure trial: Participants listen to the same 20-minute audio track once daily for 3 months. Where it is delivered The intervention is delivered in participants’ natural environments (e.g., home), at a time and in a position (e.g., sitting or lying) of their choosing. Participants are asked to keep these conditions consistent across sessions to support standardisation. Adherence (monitoring and support) Adherence is monitored using a daily self-reported diary, where participants record completion of each session and any missed sessions. The diary also captures factors that may influence outcomes (e.g., stress, illness, caffeine or alcohol intake). Participants receive instructions at study commencement and are required to maintain consistent listening conditions across sessions. A subset of participants will be invited to use a Polar chest strap based on feasibility and participant availability. This subset will be selected pragmatically, rather than randomly, according to participants’ willingness to complete the additional measurement, availability for the required recording periods, and the availability of Polar devices.