Not a medical device

Applies to every Range Freely app. Last updated 30 October 2026.

What that means in practice

• The apps record and display your heart's electrical signal and the timing between beats, and measures calculated from them, such as heart-rate variability and DFA α1. They are tools for training.
• They do not detect arrhythmias or heart attacks, and they do not interpret an ECG. A recording is shown so that you can look at it, not so that the app can tell you what it means.
• What an app shows cannot tell you whether you need care.
• If you think you may be having a medical emergency, call your local emergency number.

Research-stage measures

Measures such as DFA α1 come from published exercise-physiology research. They are valid only under certain conditions (steady exercise once you are warmed up, a clean signal), and some people's hearts do not produce the pattern they assume. The apps tell you when a reading is withheld or provisional. A reading is information for your own training, not a measurement of your health. See About DFA α1.

Training safely

You are responsible for how you exercise and for using your equipment properly. Exercise carries risk. The apps do not monitor you for safety and cannot alert anyone if something goes wrong.

See also the Terms of Use and the Privacy page.