Terms of service

Effective October 13, 2026.

These terms govern your use of the Know your Limits iPhone app (“the app”) and the knowyourlimits.fit website. By downloading or using the app, you agree to these terms. If you do not agree, do not use it.

What the app is

With your permission and in read-only mode, Know your Limits reads your Fitbit Air data available in Google Health and computes recovery, strain, sleep, biological age, migraine risk and health monitoring metrics on your iPhone. How we handle your data is explained in the privacy policy.

Not medical advice

Know your Limits is not a medical device and does not diagnose, treat, cure or prevent any disease. Its metrics are informational estimates based on published research and on data from a consumer sensor, which may be incomplete or inaccurate. Do not make decisions about your health, medication or training based on the app alone. If you have symptoms or concerns, talk to a health professional. In an emergency, call your local emergency services.

Requirements

• You must be at least 16 years old.
• You need a compatible iPhone, a Fitbit Air and a Google account with access to Google Health. Those services are governed by their own terms.

Permitted use

We grant you a personal, non-exclusive, non-transferable license to use the app on Apple devices you own or control, subject to these terms and the App Store usage rules. You must not use the app unlawfully or attempt to interfere with its operation or with the third-party services it connects to.

Third-party services

The app relies on services we do not control, such as Google Health, Fitbit and Open-Meteo. If they change, are interrupted or become unavailable, some features may stop working. We are not responsible for those services.

Open source

The app includes open-source software distributed under the Apache License 2.0. The corresponding notices are available inside the app.

No warranty

The app is provided “as is” and “as available”. To the extent permitted by law, we do not warrant that it is accurate, complete, uninterrupted or error-free, or that its metrics are fit for any particular purpose.

Limitation of liability

To the maximum extent permitted by law, we are not liable for indirect, incidental or consequential damages, or for decisions made based on information from the app. Nothing in these terms limits rights that applicable law does not allow to be limited, including your consumer rights.

Changes and termination

We may update the app and these terms. The current version will be posted on this page with its date. You can stop using the app at any time and delete your data under More → Delete all data.

Governing law

These terms are governed by the laws of the United Mexican States, without prejudice to the rights granted to you by the consumer protection laws of your country of residence.

Contact

Questions: contact@knowyourlimits.fit.