Tuned sound · Guided breath · Honest about the evidence

A session that
listens back.

Tones tuned to the Schumann resonance and the brain-wave bands. Eleven guided breathing patterns. And — if you let it — a session that follows your own heart in real time.

Radical Health builds Radical Attune: a relaxation and guided-breathing app for iPhone, iPad and Apple Watch. It synthesises every tone live instead of playing back a recording, paces your breath against patterns with their evidence printed next to them, and is straight with you about the parts of this field that are thin.

Join the early list See how it works
iPhone & iPad · iOS 17+ · Apple Watch optional · Pre-launch
A running Radical Attune session on iPhone: an amber exhale arc sweeping the screen, the cue EXHALE · 4, a 7.83 Hz Schumann · theta tone, and a live pulse card reading “waiting for a pulse — no pulse source”.
A live session · iPhone
Tones
7.83 Hz
the Schumann fundamental, synthesised — not sampled
Breath
11 patterns
eight graded against the research, three the founder's own
Lock
Breath–heart
a live coherence estimate, never a diagnosis
Data
On device
no account, no ads, no analytics, no server
Most sound-and-breathing apps have the opposite problem to most fitness apps. The science isn't wrong so much as oversold. We built the honest version.

A soothing tone gets described as though it rewires your brain, and a number with two decimal places gets treated as a measurement. Then the app sells you a subscription to believe it. Here, the tones are exact — provably, to about a trillionth of a hertz. The breathing patterns carry their real evidence grade, including the weak ones. And where the research says "we measured the brain following the rhythm but the person didn't feel better," we print that too.

How it works — three shapes of session

Three ways in.
One centre button.

Pick breath, audio, or both. Pick a length — or leave it open-ended. Tap the centre button. Everything else is optional refinement.

Breath

The ring paces you: inhale, hold, exhale, hold. Gongs mark each turn, spoken cues guide you if you want them, and haptics tap the rhythm so you can close your eyes and put the screen away.

Audio

A live-synthesised tone at the frequency you choose, delivered as a binaural beat, an isochronic pulse, or a blend of both. Add an ambient bed — surf, rain, or a warm drift — and tune the carrier, the beat, and the depth from TUNE.

Combined

The pacer and the tone together, sharing one rhythm. This is where the app can respond to you: with an Apple Watch and headphones, the tones drift a hair out of tune and then resolve into clean unison as your breath–heart lock rises. You hear yourself settle.

The Radical Attune session screen at rest: a 7.83 Hz Schumann · theta dial, a check-in row, a notice that headphones are needed for binaural, and a breath-only / audio-only / combined selector.
The session screen. Pick the shape, the length and the pattern — then the centre button.
A running Radical Attune session showing a blue inhale arc and the cue INHALE · 4 beneath the 7.83 Hz readout.
A live breath cycle. The arc fills on the inhale and empties on the exhale — blue in, amber out.
Radical Attune's pattern picker, grouped into Founder's favorites, Calm & focus, Breathe easier and Advanced, with Power breaths shown locked behind its safety gate.
Eleven patterns. Grouped, graded, and with Power breaths locked behind its safety screen.
The four things a session can use

A tone engine.
And three ways in.

One of these is the sound itself. The other three are the pacer, your body, and the room you're sitting in — each optional, each labelled.

LEVER 01

The tone engine

Every tone is computed sample by sample from a 64-bit phase accumulator, never stretched from a recording, and rendered at your device's own hardware sample rate. Binaural beats are placed symmetrically around the carrier — 200 Hz becomes 196.085 + 203.915 — so the carrier cancels in the difference and the beat equals your setting exactly, even mid-glide. Switch from speaker to AirPods mid-session and the pitch is preserved.

EXACT BY CONSTRUCTION
LEVER 02

The breath pacer

Eleven patterns, from the founder's everyday 5.5-breaths-a-minute Calm to the most-studied clinical protocols. Each one shows its timing, its evidence grade, and its primary sources before you start.

GRADED HONESTLY
LEVER 03

Your body

With permission, Apple Health supplies heart rate, resting heart rate, HRV, respiratory rate, oxygen saturation, sleep and workouts. An Apple Watch adds live heart rate during the session. No Watch? Camera heart rate can estimate your pulse from a fingertip — opt-in, on-device, and honestly labelled experimental.

OPTIONAL · ON DEVICE
LEVER 04

The room

Haptics so the phone breathes in your hand. Spatial breath, where with AirPods a soft breath rises overhead on the inhale and stays anchored in the room as you turn your head — while the tones themselves stay perfectly in tune. A Live Activity on the Lock Screen. Two Shortcuts actions so Do Not Disturb and your session start together.

EYES CLOSED, SCREEN OFF
The app, day to day

Almost nothing
to set up.

One screen, one button. Health data flows in with your permission; everything else is a chip you tap.

Find your own calmest rate

Your resonant breathing rate is personal — usually between 4.5 and 6.5 breaths a minute. Calibration walks you through five rates, and with an Apple Watch it measures how much your heart rate swings at each one, then recommends the strongest. You can always overrule it.

Plans and programs

Ready-made sequences — Sleep Descent, Calm Curve, Wind-Down, Afternoon Reset, Evening Downshift, Focus Ramp, Inward, Full Reset — plus multi-day programs: 7 Nights to Better Sleep, 5 Days of Calm, Focus Week. Or build your own.

Insights from your own sessions

It compares what you've actually run and tells you which pattern moves your breath–heart lock, your HRV, or your mood most. It refuses to make a recommendation until a comparison has at least three readings, and it labels small samples as hints rather than proof.

Apple Watch

Live heart rate on your wrist, a breath pacer that taps the rhythm, and a "Don't fill your Exercise ring" setting that's on by default — so a calm session doesn't get logged as a workout unless you want it to.

Apple Health, both ways

Finished sessions are written as Mindful Sessions. Choose a mood check-in and it writes a State of Mind entry — only when you choose it.

Your own audio

Import your own tracks, stream a URL, or add a podcast by RSS feed or an Apple Podcasts / Spotify show link — which is used only to find the publisher's open feed. Downloaded episodes live on your device and you can delete them.

Wellness suggestions, not nags

Finished a workout, slept badly, resting heart rate above your recent average, or it's simply late — the app may offer a fitting session, with the reason written out. It never starts one on its own.

One centre button

Breath, audio, or both; a length or open-ended. Everything past that — the carrier, the beat, the depth, the ambient bed — is a chip you tap in TUNE, not a wizard you have to finish.

iPhone and iPad

Same app, same sessions, on iOS 17 and later. An Apple Watch on watchOS 10+ is optional, and every core feature works without one.

Why it's different

Not another
soothing playlist.

Most audio apps play at you, and most breathing apps hand you a timer. Here's where this one is built differently — on purpose.

It responds to you

Most audio apps play at you. In a combined session with a Watch and headphones, the sound resolves as your breath and heart lock together — the app's core output is a reaction, not a recording.

vs. streaming meditation libraries

Exact, and it shows the measurement

The app publishes its own frequency accuracy, including the one limit no app can beat: every device's audio clock has a crystal tolerance of roughly ±0.005 Hz at a 200 Hz carrier. Far below audible, and far below the Schumann resonance's own natural drift between about 7.4 and 8.0 Hz.

vs. "528 Hz healing tones" uploads

Honest by construction

The evidence board includes the studies that found nothing. No streaks to lose, no leaderboards, no confetti, no fake urgency.

vs. everyone

Duet

Two phones side by side, one shared soundscape that only resolves into tune when both of you have settled together. The pattern, the timing and one live coherence value pass directly between the two devices — encrypted, peer to peer, and never through us.

nearby, two iPhones

A one-of-a-kind keepsake

Every finished session can become a glyph drawn from your own heart's rhythm that day. Keep it or share it. It's a souvenir, and the app says so.

a souvenir, not a score
Labs — experimental, and labelled that way

Switched off
until you want them.

The newest ways a session can answer your body live. Each is independent, each is off by default, and each is a relaxation feature rather than a treatment.

Responsive sound

Tones resolve into unison as your breath–heart lock rises, and pulse gently with your heartbeat.

Needs an Apple Watch and headphones · combined sessions

Coherence signature

The session glyph, drawn from your heart's rhythm.

Any session · richer with Watch data

Sleep hand-off

On an open-length session, eases the sound to silence once your heart rate has settled low and held there.

Needs an Apple Watch · open-length audio sessions

Duet

The shared nearby session — one soundscape across two phones, passing directly between them.

Needs a second nearby iPhone running Radical Attune

Phone haptics

The phone breathes in your hand, so you can pace a session with the screen off.

For iPhone without an Apple Watch · breath sessions

Camera heart rate

An experimental fingertip pulse estimate using the rear camera and torch. Unvalidated, and used only when no Apple Watch reading is available.

For iPhone without an Apple Watch

Spatial breath

Head-tracked breath that stays anchored in the room while the tones stay in tune.

Needs AirPods · audio sessions

PulseWeave Undertow

An ambient bed whose loudness rises and falls in step with the session's beat frequency, so the whole soundscape carries the rhythm.

Audio sessions
The science — the honest version

Sourced.
Including the nulls.

Every breathing pattern and every sound method in the app carries an evidence grade and its primary sources — chosen to include the studies that found no effect, not only the flattering ones. Sources verified June 2026.

Breathing
Well studied
Slow-paced breathing (about 6 breaths a minute). The most-studied pace, and the everyday default. Meta-analyses of slow breathing and HRV support it; you can tune it to your own rate.
Well studied
Pursed-lip breathing. A long exhale through pursed lips eases breathlessness and recovery after exertion. Best-supported in COPD rehabilitation literature. Short rounds; it's an ease-and-recovery exercise, not a stress tool.
Some evidence
Cyclic sighing. A deep inhale, a short top-off, then a long exhale. Came out favourably in a 2023 breathwork-versus-meditation randomised trial.
Some evidence
Belly (diaphragmatic) breathing. Breathe low rather than high in the chest. The foundation under every other pattern.
Some evidence
Alternate-nostril breathing. Supported by a meta-analysis of 14 randomised trials on blood pressure. A deliberate, seated practice.
Early evidence
4-7-8. A structured wind-down with a long exhale and a hold. Small acute studies only. Best before sleep, not all day — the 7-second hold can feel light-headed.
Early evidence
Box breathing (4·4·4·4). Easy to remember, good for composure. Head-to-head trials don't establish it as better than the alternatives.
Early evidence
Power breaths (cyclic hyperventilation). High-arousal and stimulating, the opposite of the calming patterns. Gated behind a safety warning. See Safety below.
SoundThis is the humble half of the app, on purpose. No sound method reaches the top grade — the best any of them manages is early evidence.
Early evidence
Binaural beats. Two tones a few hertz apart; the brain conjures a third pulsing beat at the difference, which is why headphones are required. A meta-analysis of 22 studies found small-to-moderate benefits for anxiety, memory and pain, and a surgical trial roughly halved pre-operative anxiety against the same audio without beats. But careful EEG work often finds the brain doesn't actually lock onto the beat — so the calm you feel may come from slow, pleasant sound and relaxed expectation rather than entrainment. Worth using. Worth not over-believing.
Very limited
Isochronic tones. A single tone pulsed cleanly on and off, so the rhythm is in the sound itself and works on a speaker. A 2024 EEG study found they shift brain-wave power more than binaural beats do — the cortex really does track them. The gap: that's a measurement of brain activity, not of feeling better. There are essentially no clinical trials on mood, sleep or focus.
Early evidence
Brain-wave bands (delta · theta · alpha · beta · gamma). The brain measurably tracks a steady rhythm — a real, replicable effect. But "the EEG synced" is not "the person improved": a 40 Hz study produced textbook entrainment with zero cognitive gain, and effects rarely outlast the sound.
Early evidence
Solfeggio frequencies (528 Hz and others). Devised in the late 20th century, not ancient. The well-supported part is that pleasant, slow, consonant music is one of the best-evidenced ways to unwind — a meta-analysis of 104 trials across 9,600+ people found music reliably lowers stress hormones, heart rate and anxiety. What isn't established is that these specific numbers do anything beyond what any pleasant music does; the most-cited 528 Hz study had nine people and no control group. Enjoy them for how they sound.
Very limited
Schumann resonance (7.83 Hz). The physics is real and well-established: global lightning rings the cavity between the Earth's surface and the ionosphere, and the fundamental sits near 7.83 Hz. It's an appealing target because that falls in the brain's theta range, and observational work has linked higher Schumann and geomagnetic power to greater HRV. But that work tracks an ambient electromagnetic field over weeks, and the association runs both ways across studies. No human trial shows a 7.83 Hz audio tone reproduces any of it. A beautiful organising idea and a sensible calm-band target — not a proven remedy.
What we'll never claim
  • ✕ That these tones treat, prevent or diagnose anything. It's a relaxation tool.
  • ✕ That brainwave entrainment is settled science. The careful studies disagree with each other.
  • ✕ That a measured EEG shift means you feel better. Those are two different findings.
  • ✕ That 528 Hz or any specific number has a proven physiological effect of its own.
  • ✕ That an audio tone reproduces what the Schumann resonance research measured. No trial shows it.
  • ✕ That camera heart rate is medical-grade. It's an experimental estimate, and unvalidated.
  • ✕ That a breath–heart coherence number is a clinical measurement. It's a non-clinical estimate.
  • ✕ That any of this replaces a professional. For anything medical, see one.

The honest part: the evidence backs some of the methods — slow breathing most of all. It does not back a study of this app, and we'd rather say that than pretend otherwise.

See all eleven patterns, every sound method, and all 25 sources

Safety — Power breaths

One pattern
needs a warning.

Read this before you try it

Power breaths — 30 fast breaths, then a breath-hold, repeated — is the only advanced hyperventilation and breath-hold pattern in the app. It's stimulating rather than calming, gated behind a safety screen you must read, and unavailable in Duet.

Never practise it in or near water, while driving, or while standing — you can faint. Sit or lie down. Avoid it during pregnancy, or if you have epilepsy, a heart condition, or a history of fainting. If you feel unwell, stop.

Gated · safety screen required · not available in Duet
Privacy

On your device.
Not on our servers.

No account, ever

No login, no profile, no Radical Health server. Nothing to sign up for.

Your sessions stay local

Settings, tunings, plans, session history, ratings, mood check-ins, and every health-derived value live in the app on your device. We can't reach them.

Health data is read, not sent

With your permission the app reads from Apple Health and processes it on device. It writes back only Mindful Sessions, and a State of Mind entry when you choose a mood check-in. Revoke access any time in iOS Settings.

Camera frames are never stored

They're computed on device and discarded.

Duet goes device to device

The pattern, timing and one live coherence value pass directly between the two phones over encrypted Apple Multipeer Connectivity. We never see it.

No ads, no tracking, no analytics SDK

There is nothing to sell because we don't hold it.

Read the full Radical Attune privacy policy →

Sit down.
Breathe out.

Radical Attune is currently pre-launch — not yet on the App Store. Join the early list to be first in.

No spam, no nagging — one email at launch. That's the whole promise.
✓ You're on the list. We'll reach out at launch — nothing before.