Privacy policy

The short version. Rheo keeps what it needs to run your training log. Recordings of your sets, with your heart rate and body measurements, are uploaded to train Rheo’s own models once the app has told you so, and you can turn Contribute recordings off in Profile at any time. We never sell your data, show ads, or put analytics, advertising or crash-reporting SDKs in the app.

Who we are

Rheo Fitness (“Rheo”) is an iPhone and Apple Watch app for logging strength training. It is made by Owen Huang, an independent developer in Ontario, Canada (“we”, “us”), who is responsible for your data and accountable for this policy. It covers the app and this website. Questions go to owenhuang623@gmail.com.

What we collect

From your account. You sign in with Apple. We store the email address Apple shares (which may be a private relay address), the name you give, and an internal user id. Accounts created earlier with an email and password can still sign in that way; the password is stored only as a hash by our database provider. If we offer email sign-up, the app checks a new password against known breaches by sending the first five characters of its SHA-1 hash, never the password, to Have I Been Pwned.

From what you log. Workouts, sets (exercise, weight, reps, the times of each rep, and where the set sits in a watch recording), notes, templates and custom exercises. For each set we keep how its label was made (entered by you, or suggested by a model and then accepted or corrected) and, where a model was involved, what it predicted, how confident it was, and which model version made the guess.

From your profile. The bodyweight and height you type in, how long you have trained, the kind of gym you use, your weekly session target, which wrist wears the watch, and your units.

From each watch recording, while you contribute recordings. The raw recording and what is stored beside it, and a short description of it: start and end times, watch model, watchOS and app version, the sample rate and sample count, the wrist and crown side, the sensor mode, and a device identifier. That identifier is Apple’s identifierForVendor, which is shared by apps from one developer on that device; it is not a serial number. With contributing off, none of this is uploaded. See Contributed recordings.

From your requests. Our database provider logs the IP address and user agent (which includes the app version) of each request the app makes. If you opted in on your device to share analytics with developers, Apple may send us crash reports.

From this website. If you join the waitlist we store your email address, which part of the site you joined from, and when. The site sets no cookies and runs no analytics; it only notes in your own browser that you joined, so the form does not ask again. Waitlist entries are kept apart from app accounts.

How we use it

• To run your training log, sync it across your devices, and restore it on a new phone.
• To show progression and coaching computed from your own log.
• To train and evaluate Rheo’s models, from contributed recordings only.
• To keep the service secure, fix faults, and recover from failure.
• To answer you when you write, and to tell waitlist members when the app is available.

Contributed recordings and model training

When you record on the watch, it saves the raw wrist motion (accelerometer and gyroscope) and passes it to your phone. Beside it the app stores your heart rate during the workout, your weight (from Apple Health, or as you typed it in Profile) and height from Apple Health, the sets you marked, and the device details above. Together that is a recording.

Contribute recordings is on by default, and nothing is uploaded until the app has told you so: one sentence when you create your account, or a one-time notice if you signed in without seeing it. Going on past that sentence is your consent, and the app records when you gave it and against which version of this policy. You can decline in the notice, and turn it off at any time in Profile. A different account signing in on your phone is asked again. Turning it off stops future uploads and the descriptions that go with them, and recordings that were never uploaded are then deleted from your phone 30 days after they were made; turning it back on within that time uploads the ones still there. Turning it off does not delete recordings already uploaded. To remove those, see Retention and deletion.

Contributed recordings are used only to build and test Rheo’s own models for detecting sets, recognising exercises and counting reps. They are never sold, never used for advertising, and never given to third-party AI providers. To train, we download them, with the labels from your workouts, to our own computer, where they are filed under an internal user id rather than your name or email.

Apple Health and motion data

With your permission, the watch app reads heart rate and active energy to show during a workout, and your latest body mass and height to store with each recording. It writes the finished workout to Apple Health, with the heart rate and active energy measured during it. It does not read biological sex. Active energy is never stored on our servers; heart rate, body mass and height leave your phone only inside a contributed recording. Your weight may also come from what you type in Profile.

We do not use Apple Health or Motion & Fitness data for advertising, marketing or data mining, do not share it with anyone for those purposes, and do not store it in iCloud. You can change these permissions at any time in the Settings and Health apps.

Where data is stored, and who processes it

Your account, training log and contributed recordings are stored with Supabase (database, sign-in and file storage) on Amazon Web Services in the United States (us-east-1). Each account can reach only its own rows. As the developer, Owen Huang has administrative access to all stored data, and uses it only for the purposes above. Other services that handle data for us:

• Apple, for Sign in with Apple, Apple Health and the App Store.
• Cloudflare, which serves this website and sees the IP addresses of its visitors.
• Resend, only if we offer email sign-up or password reset, to send those emails.
• Have I Been Pwned, only for the password check described above.

Sharing

We do not sell, rent or trade your data, use it for advertising, or share it to track you across apps and websites. We disclose it beyond the processors above only if the law requires us to.

Retention and deletion

Your training log and profile are kept until you delete your account. On your phone, a recording is deleted 14 days after it was made once it has been uploaded. While you contribute, one that has not uploaded yet stays until it has. With Contribute recordings off, recordings that were never uploaded are deleted from your phone 30 days after they were made. The watch deletes each recording 14 days after it was made. Recordings on your phone are excluded from iCloud Backup, so restoring a phone from a backup does not restore them.

Delete Account (Profile → Delete Account) revokes Sign in with Apple, deletes your account and every row stored for it, deletes your recordings from cloud storage at once, and erases them from your phone. The phone tells the watch the account is gone; recordings already on the watch clear within 14 days. It does not reach workouts already saved in Apple Health, which you manage in the Health app. Copies outside the live service go on this schedule:

• Offline copies of contributed recordings, in our recording backup and our training datasets on our own computer, are not removed automatically when the account is deleted. Email us after deleting your account and we will remove them and confirm it within 30 days.
• Database backups, including account data, are taken twice a day and kept on our own computer: daily for 14 days, then weekly, for no more than about 13 weeks. They are used only to recover from a failure.
• Trained models hold learned parameters, not recordings, and one person’s contribution cannot be extracted from them. Models trained after your data is removed are trained without it.

You can also ask us to remove your contributed recordings without deleting your account, or to remove a waitlist address, by email. We reply within 30 days.

Your rights and choices

You can ask to see the data we hold about you, correct it, or delete it; much of it you can correct or delete in the app yourself. You can withdraw consent at any time: turn off Contribute recordings, or revoke Health permissions. Email us for anything the app does not do. If you are not satisfied with our answer, you can complain to the Office of the Privacy Commissioner of Canada or to the data protection authority where you live.

Legal bases (EU and UK)

We keep your account and training log because they are needed to provide the app you asked for (contract). Health data — the bodyweight and height you choose to enter in your profile, and the heart rate and body measurements in contributed recordings — we process only with your explicit consent. Entering a bodyweight or height is optional; you can change either in Profile, and delete your account or email us to remove them. Recordings are uploaded only after the app has shown you the consent sentence described above, and you can withdraw by turning Contribute recordings off at any time. We keep logs and backups for security and to recover from failure (legitimate interests).

International transfers

Your data is stored in the United States, wherever you live, and may be accessible to authorities there under US law.

Children

Rheo is for people aged 16 or over, because it processes health data, and we do not knowingly collect data from anyone younger. If you believe someone under 16 has given us data, email us and we will delete it.

Security and breaches

Data travels encrypted, each account is kept apart from the others in the database, the recordings store is private, and backups stay on a computer only the developer uses. If a breach creates a real risk of significant harm, we will tell the people affected and the Office of the Privacy Commissioner of Canada as soon as we can.

Changes

When this policy changes, we update this page and its effective date. A material change to how we use motion or health data will be shown in the app before it applies to your recordings, and you can turn Contribute recordings off at that point.

Contact

Owen Huang, Ontario, Canada — owenhuang623@gmail.com