The app
The gym for your nervous system.
An iPhone app that measures your autonomic nervous system in two minutes, trains it with paced breathing scored breath by breath, and turns months of your own data into a clinical report I read before it reaches you.
A day in the app
Two minutes in the morning. Ten minutes when you train.
That is the whole ask. The rest is the app's job.
Seated and still, before coffee and before the phone. A fingertip over the camera, or any monitor you already own, taken the same way every day.
Heart rate, RMSSD, SDNN and the full power spectrum, with your own breathing rate marked on the curve.
Resonance breathing with a pacer, and a score on every breath as you take it, so you learn the feel rather than reading about it after.
Weekly and monthly reports built from your own history, reviewed by me before they reach you.
A session, as it happens
Watch it find resonance.
A session recorded straight off the screen, so you can watch the pacer, the per breath scoring and the state changes happen at the speed they actually happen.
Recorded from the app · not an animation
The curve is heart rate, beat to beat. Breathe in and it climbs, breathe out and it falls, and when the breath lands on the right rhythm the two lock together and the swing gets much larger. That swing is the training stimulus. Everything else on the screen is there to help you find it and hold it.
The app scores every breath and tells you which state you are in, so the feedback arrives while you can still act on it rather than afterwards.
The first minute or two. The breath is on the pacer but the heart rate has not organised around it yet.
The swing is building. This is the part that takes practice, and the part most people never get feedback on.
Heart rate and breath in phase, with the largest swing the system will produce. Hold it here and this is the state you are training.
The screens
What it actually looks like.
Real screens from the app, with real readings. Nothing here is a mockup.
What it measures
The same measures behind the reports I produce in the clinic.
Time domain
- HRV-CV, the headline measure of stability, where lower is better. Under 8% stable, 8 to 15% caution, above 15% high
- RMSSD and lnRMSSD, the standard indices of parasympathetic activity
- SDNN and pNN50, overall variability and beat to beat differences
- Heart rate, resting and during training
Frequency domain
- The full power spectrum across VLF, LF and HF bands
- Your own breathing rate marked on the curve, so the spectrum can be read rather than guessed at
- HF power and lnHF for the parasympathetic band
- Heart rate amplitude during paced breathing, the peak to trough swing that shows the baroreflex loading
Two clinical decisions worth knowing about
Every reference range is your own history.
There are no population norms anywhere in the app. Comparing your nervous system to a stranger's tells you almost nothing useful, so the app does not do it. Your baseline is yours, and progress is measured against it.
A bad reading is thrown away, not stored.
If more than 15% of beats jump, the recording cannot be cleaned into a real number, and the app asks you to measure again rather than filing a placeholder. A number you might later mistake for data is worse than no number at all.
The part that is not software
I read the reports before they reach you.
The app writes the numbers. I decide whether what they are saying is right. Every weekly and monthly review is built from your own data by the same validated pipeline behind my clinic reports, and then it comes past me before it comes to you.
This is the part that does not scale, and it is deliberate. An app that hands out automated verdicts on a nervous system it has known for nine days is not a clinical tool, it is a horoscope with a chart.
Dr. Jay AI covers the hours in between. It is built from my published work and it can see your readings, so the answer you get at eleven at night is grounded in your data rather than a search result.
Being straight with you
What this is not.
- It is not a medical device. It does not diagnose, treat, or monitor any disease, and it is not a substitute for care from your own clinician
- It will not work in a week. Autonomic adaptation shows up across months, which is why the app is built around a streak rather than a session
- It requires an iPhone, and either good light for the camera or a monitor that broadcasts beat to beat intervals
- It is not a passive tracker. If you want a number to appear on your wrist without doing anything, a wearable already does that and this is not for you
Questions
The things people ask first.
How do I actually get in?
By invite code. There is no public download and no App Store listing yet, so you cannot simply install it and sign up. When a place opens I email you a code along with a link to install the app, and the code turns into your account when you redeem it.
Codes are single use and they expire, so use one when it arrives. You do not have to sign up with the same address the code was sent to, and if yours lapses I will issue another.
It is iPhone only. No Android version and no web version yet. If you are not on an iPhone you can still join the list, and you will hear from me when that changes.
What do I need to take a reading?
Your phone, and nothing else. The app reads your pulse straight from the camera, so you can start the morning you get access without buying anything.
If you already own a heart rate monitor, use it. Any device that broadcasts beat to beat intervals over Bluetooth works: the raw RR intervals, sometimes called IBI, which is the signal every HRV measure is calculated from. That is not a short list of approved hardware. It is a standard, and anything that speaks it is fine.
Chest straps, armbands, earbud and finger sensors all qualify. What matters is that the device sends the intervals themselves, not an averaged heart rate number.
Is a monitor better than the camera?
More forgiving, yes. The camera is accurate when you hold still and keep steady contact, but it is unforgiving about movement, and a reading it cannot clean is thrown away rather than stored. A strap or armband tolerates a restless morning far better.
Start with the camera. If you find yourself re-measuring often, that is the moment a monitor earns its money, not before.
How much time does this actually take?
Two minutes for the morning check, seated and still, before coffee and before the phone. Ten minutes for a breathing session on the days you train.
Doing it the same way every day matters more than doing it at a precise time, because the whole point is a baseline that is comparable to itself.
How long before I see anything change?
Weeks for the feel of it, months for the data. Autonomic adaptation is slow in the way strength is slow, which is why the app is built around a streak rather than a session, and why the reports look at weeks rather than days.
Anything promising a transformed nervous system in seven days is selling you a mood, not an adaptation.
Do I need to be an athlete for this to be worth it?
No. Autonomic flexibility is what lets you fall asleep quickly, come down from a hard conversation, and hold steady under pressure. Athletes care about it because recovery is their job, but the capacity itself is general.
Is this a medical device?
No. It does not diagnose, treat, or monitor any disease, and it is not a substitute for care from your own clinician. It is a training tool with a measurement system attached.
What happens to my data?
It stays yours. No video or image from the camera is ever recorded or transmitted: the app reads the brightness of each frame, turns it into a number, and discards the frame. What leaves your phone is a list of intervals between heartbeats.
There is no analytics, no advertising and no third party tracking in the app. You can delete everything from inside it. The full detail is in the privacy policy.
What if I miss days?
Nothing breaks. The app compares you to your own history, so a gap is a gap rather than a failure, and the reports account for how many readings actually happened. Missing a week is worth noticing; missing a Tuesday is not.
Something not answered here? App support, or email me directly.
Request access
The app is in limited release.
It is running with clients in the practice now and opening in stages. Leave your email and you will hear from me directly when a place is available, along with the occasional note on the model as it develops.
Two things worth knowing before you leave your address. Entry is by invite code only: there is no public download, so when a place opens I send you a code and a link to install. And the app is iPhone only for now, with no Android or web version yet. If you are not on an iPhone, still leave your email and I will keep you on the list for when that changes.
It is $19.99 a month once you are in, cancel any time, no notice required. Early places carry a reduced founding rate that I confirm when I send your code.
No sequence of sales emails. I write when there is something worth saying.