Sound that slows you down.
BASE 90 is an independent research study measuring how a 35-minute audio protocol affects heart rate, heart rate variability and skin temperature, using participants’ own wearable devices.
Can sound help the body shift into recovery?
Chronic daily pressure keeps many people in a state of constant alertness. On a wearable, this appears as an elevated resting heart rate and reduced heart rate variability (HRV).
BASE 90 is an independent research project. It investigates whether a precisely engineered audio session can help the body move into a rest state, and whether that change is visible in objective data rather than only in how it feels.
The protocol is built on a tempo framework centred on 90 BPM. The tempo slows early in the session to guide the listener's rhythm downward.
| Duration | A 35-minute session composed of six synchronised audio layers. |
|---|---|
| Tempo | A rhythm based on 90 BPM that slows at approximately minute two. |
| Sound design | Binaural and spatial audio, low-frequency textures between 20 and 140 Hz inspired by feline purring, and very quiet spoken layers mixed well below the music. |
| Comparison | Evaluated against standard relaxation music. |
What we measure
For each metric, we compare the value at the start of a session with the value at its end.
| Heart rate | A falling heart rate at rest is the most direct indicator of physical relaxation. |
|---|---|
| Heart rate variability | The variation between consecutive beats. An increase indicates that the nervous system is moving into recovery. |
| Stress score | The composite indicator your device calculates, such as stress level, Body Battery or readiness. |
| Skin temperature | Warmer extremities suggest that peripheral blood vessels are relaxing, a common sign of calm. |
Pilot results
Participants listened while wearing an Ultrahuman Ring and an Amazfit GTR 2. After the tempo slowed, their recordings showed:
- Heart ratea marked decrease
- HRVan increase
- Skin temperaturean increase
These changes were not observed with standard relaxation music.
These are preliminary observations from a small group of participants. This open study will test whether they hold across a larger and more varied sample of listeners and devices.
The audio session
Choose a quiet environment, sit or lie down, and keep your watch or ring on.
Session complete.Please record your data again, then submit both screenshots.
Continue to the formBefore you start, take a screenshot of your device data, and take another immediately after the session. This is not a medical treatment. Do not listen while driving or operating machinery.
Participate in the study
The study takes four steps, completed in this order.
- Baseline measurement2 min
Sit still, then take a screenshot of your heart rate, HRV and stress score.
- ListenFull session
Wear headphones, play one of the sessions above and let it run to the end.
- Follow-up measurementImmediately
Take a screenshot of the same metrics immediately after listening.
- SendOnline form
Upload both screenshots and describe how you felt.
Participant feedback
Collected through the study form and published with permission.
Share your feedback
Already listened? Rate the session and describe how you felt.
References
- Karaki, Y. (2026). Nonagesimal Auditory Neuromodulation: Engineering a 1.5 Hz Micro-Calibrated Multi-Track Binaural Protocol for Autonomic Vagal Entrainment and Stress Reclamation. Zenodo (preprint). doi.org/10.5281/zenodo.22145435 (opens in a new tab)
- Thayer, J. F., & Lane, R. D. (2009). Claude Bernard and the heart–brain connection: further elaboration of a model of neurovisceral integration. Neuroscience & Biobehavioral Reviews, 33(2), 81–88.
- Porges, S. W. (2011). The Polyvagal Theory: Neurophysiological Foundations of Emotions, Attachment, Communication, and Self-regulation. W. W. Norton & Company.
- Chaieb, L., Wilpert, E. C., Reber, T. P., & Fell, J. (2015). Auditory beat stimulation and its effects on cognition and mood states. Frontiers in Psychiatry, 6, 70.