Privacy Policy

Effective March 2023 · Last updated September 24, 2026

The short version: TeraThreshold reads your runs from Garmin with read-only access, uses them to compute your form, training load and injury-risk analysis, and stores them so you can see your history. We do not sell your data, we do not show ads, and you can delete your account and everything in it from the app's Settings at any time. If you apply to the beta, we use your application only to review it, and if we accept you, we give Apple only your email address so TestFlight can invite you.

This Privacy Policy explains how TeraThreshold LLC ("TeraThreshold", "we", "us") collects, uses, shares and protects information when you use the TeraThreshold iOS application (the "App"), the website at terathreshold.com (the "Site") and related services (together, the "Service"). By using the Service you agree to the practices described here. If you do not agree, please do not use the Service.

1. Information we collect

Information you provide

Account information. When you sign in with Garmin we receive only an identifier for your Garmin account; Garmin does not share your email address or name with us. If you sign in with Apple, we receive the identifier and email address Apple shares with us.
Body check-ins. Areas of your body you mark as tight, sore or painful, with the severity and date. This is health information and you choose whether to enter it.
Profile settings. Your birth year (used to seed a heart-rate estimate until your training data refines it), unit preferences, time zone, theme and notification settings.
Beta applications. What you enter when you apply to the TestFlight beta on the Site: your name, email address, marathon result, weekly distance, links to your official result and your training log, your confirmations and anything else you write. See Beta applications below.
Support messages. Anything you send us at support@terathreshold.com.

Information from connected services

Garmin. With your authorization, we receive your activities and activity files (route, pace, heart rate, cadence, running dynamics such as ground contact time, vertical oscillation, stride length and left/right balance, and power if a compatible sensor is present), your Garmin profile, and wellness summaries Garmin makes available such as sleep and heart-rate variability. Historical activities are imported only if you grant Garmin's historical-data permission. Our access is read-only: we never write to your Garmin account.
Withings (optional). If you connect a Withings account, we receive weight measurements, sleep summaries and heart-rate measurements that Withings makes available.
Body-composition scales. If your Garmin account includes scale measurements, we receive weight and body-composition values.

The App does not currently read data from Apple Health, Strava or any other service. A Garmin Connect or Strava link you include in a beta application is opened by hand only to review it. Some builds of the App may ask for Apple Health permission; we do not read or upload Apple Health data today and will update this policy before we do.

Information collected automatically

Device and app data. A device token for push notifications, your app version, your IP address, and technical logs (request identifiers, timestamps and error messages) needed to run and troubleshoot the Service.
Subscription status. Whether your account is on a free plan, a trial or a paid subscription, and the associated App Store transaction identifiers. Apple processes your payment; we never see your card details.
Site visits. Our Site is hosted on Cloudflare, which receives your IP address and standard request data when a page loads. Fonts, images and video are served from our own domain. The Site sets no tracking cookies and uses no analytics scripts.

Notice at collection

For California residents, the categories of personal information we collect, where it comes from, why we use it and how long we keep it:

Category	Examples	Source	Purpose	Retention
Identifiers	Garmin or Apple account identifier, email address (Apple sign-in, beta application or earlier invite request), device token, IP address	You, Garmin, Apple, your device	Sign-in, notifications, security	Life of your account
Health information (sensitive)	Heart rate, heart-rate variability, sleep, weight, running dynamics, body check-ins, our computed scores	Garmin, Withings, you	Providing the analysis you request	Life of your account
Precise geolocation (sensitive)	GPS routes inside your activity files	Garmin	Pace, elevation, terrain and race analysis	Life of your account
Commercial information	Subscription tier, trial status, App Store transaction identifiers	Apple, our systems	Managing your subscription	Life of your account
Internet or network activity	Request logs, error logs, app version	Your device	Running and troubleshooting the Service	Rotated on a short schedule
Profile settings	Birth year, units, time zone, theme, notification preferences	You	Personalizing the Service	Life of your account
Beta applications	Name, email address, marathon result and bib number, results link, weekly distance, training-log link, your confirmations, anything else you write in the form, and the country your request came from	You, Cloudflare	Reviewing your application and sending your TestFlight invite	Declined: deleted within 90 days of the decision. Accepted: until 90 days after you leave the beta or it ends

We use sensitive personal information only to provide the Service you request and never for advertising or profiling unrelated to the Service. We have not sold or shared personal information in the preceding twelve months and do not do so now.

2. How we use information

To compute and show you your analysis: form scores, durability, training load, injury-risk scores, heatmaps, race predictions, training paces, heart-rate zones and coaching suggestions.
To keep your history so you can compare runs over time.
To send notifications you have enabled, such as when your profile is ready, when a run has been analyzed, or when your injury-risk level changes.
To provide, maintain, secure and improve the Service, including diagnosing errors.
To manage your subscription and trial.
To respond to your support requests.
To comply with law and enforce our Terms of Service.

Our analysis is computed by our own software from your data. It is designed to inform your training decisions, not to diagnose or treat any condition. See the Terms of Service for the full health disclaimer.

3. How we share information

We do not sell your personal information and we do not share it with advertisers. We share information only as follows:

Service providers. We host the Service on Amazon Web Services in the United States, where your data is stored and processed. Apple processes App Store purchases, delivers push notifications and, if we accept your beta application, receives your email address so TestFlight can send your invitation. Cloudflare hosts the Site and stores beta applications. These providers process data on our behalf under their own security commitments and do not use it for their own purposes.
Connected services. Garmin and Withings receive the authorization requests needed to connect your account and know that you have connected it. We do not send your analysis back to them.
Legal. We may disclose information if required by law, subpoena or legal process, or to protect the rights, safety or property of TeraThreshold, our users or others.
Business transfers. If TeraThreshold is involved in a merger, acquisition or sale of assets, your information may be transferred as part of that transaction. We will notify you before your information becomes subject to a different privacy policy.

4. Security

The credentials that let us read your Garmin or Withings data are stored encrypted at rest using AWS Key Management Service. Your sign-in is handled by Garmin or Apple and by AWS Cognito; TeraThreshold never sees your Garmin or Apple password. Data moves between the App and our servers over encrypted connections. No system is perfectly secure, and we cannot guarantee absolute security, but we work to protect your information with appropriate technical and organizational measures.

5. Retention and deletion

We keep your information for as long as your account exists so that your history and baselines remain available.

You can delete your account from the App under Settings. Deletion is scheduled with a 30-day window during which you can cancel it from Settings > Account in the App. At the end of that window we revoke our Garmin authorization, delete the credentials we hold for Garmin and Withings, and permanently delete your account, activities, analysis, check-ins and files from our systems. Copies in encrypted backups are purged on the backup rotation schedule. We keep a minimal record of the deletion request (account identifier, email address if we have one, and dates) for 24 months to show that the deletion was carried out. Disconnecting Garmin from Settings without deleting your account revokes our access but keeps your history until you delete the account.

You can also remove TeraThreshold's access at any time from your Garmin Connect account settings. Because Withings does not let us revoke authorizations on your behalf, remove TeraThreshold from your Withings account settings if you want it gone there too.

6. Your choices and rights

Access and correction. Your activities, analysis and settings are visible in the App. Contact us for a copy of your data in a portable format.
Deletion. Delete your account from Settings as described above, or email us.
Beta applications. Withdraw your application or have it deleted by emailing support@terathreshold.com from the address you applied with.
Notifications. Turn push notifications off in the App's Settings, or in iOS Settings for TeraThreshold.
Connected services. Disconnect Garmin or Withings from the App's Connected Services, or from the provider's own settings.

Depending on the state you live in, you may have additional rights under laws such as the California Consumer Privacy Act (as amended by the California Privacy Rights Act) and similar state privacy laws, including the right to know what personal information we collect and how we use and share it, to access, correct, delete or port your data, to limit the use of sensitive personal information such as health data, and to opt out of the sale or sharing of personal information. We do not sell or share personal information for cross-context behavioral advertising. To exercise any right, email support@terathreshold.com or, for deletion, use Settings in the App; you may also designate an authorized agent to act for you. We verify requests by matching them to your signed-in account or to the email address on file, and respond within the time required by applicable law. We do not discriminate against you for exercising your rights.

7. United States only

The Service is offered to users in the United States and our servers are located there. If you use the Service from outside the United States, you do so on your own initiative and your information will be processed in the United States.

8. Children

The Service is not directed to children and we do not knowingly collect information from anyone under 16. If you believe a child has provided us with information, contact us and we will delete it.

9. Beta applications

The TeraThreshold beta is open by application to sub-elite and elite marathoners who live in the United States. When you apply on the Site, we collect:

Who you are. Your name and email address.
Your proof. The marathon you apply with (race, date, finish time and, if you give it, your bib number) and a link to its official results; your average weekly distance over the last 12 weeks and a link to your training log, such as your Garmin Connect or Strava profile; and anything else you write in the form.
Your confirmations. That you have an iPhone and a Garmin watch, that you live in the United States, and that the result and the training log are yours.
Request details. The date of your application and the country your request came from, as reported by Cloudflare. To limit abuse, we count requests from each network for one hour using a one-way hash of your IP address, not the address itself.

How applications are decided. The form checks the marathon time, race date and weekly distance you enter against the published standard. If they are below it, the form tells you why and we do not store the application. Every application that meets the standard is reviewed by a person, who decides whether to accept it. We check an application by opening the links you give us; we do not sign in to those services as you, and nothing from your application is added to your TeraThreshold account.

Who sees it. Only the TeraThreshold team, through a private review page. Cloudflare stores applications for us as our service provider. We do not sell applications or share them with races, coaches, sponsors or advertisers. If we accept you, we give Apple your email address, and nothing else from your application, so TestFlight can email your invitation; Apple handles it under its own privacy policy.

How long we keep it. We keep an application while it is under review. If we decline it, we delete it within 90 days of our decision. If we accept it, we keep it while you are in the beta and delete it within 90 days after you leave the beta or the beta ends. If you apply again with the same email address, the new application replaces the earlier one; we keep the earlier version with it and delete both together.

Earlier invite requests. Before applications opened, the Site asked only for an email address to send a TestFlight invite. We keep the addresses we received then, with the date and country of each request, while the beta runs.

Withdrawal and deletion. To withdraw your application or have it deleted sooner, email support@terathreshold.com from the address you applied with. If you were accepted, we also remove you as a tester in TestFlight. To stop testing without deleting anything, tap Stop Testing in TestFlight.

10. Beta software

While the App is distributed through Apple's TestFlight program, Apple also collects crash logs and usage data under the TestFlight terms and Apple's privacy policy. Beta versions may change how data is collected or processed; we will update this policy when they do.

11. Changes to this policy

We may update this policy from time to time. We will post the new version at terathreshold.com/privacy with a new effective date and, for material changes, notify you in the App or, where we have an email address for you, by email before they take effect. Continued use of the Service after the effective date means you accept the updated policy.

12. Contact

Questions or requests about your privacy: support@terathreshold.com.