What optical sensing does
PPG uses light reflected from tissue to estimate pulse-related changes at the wrist. Motion, skin contact and environmental conditions can affect signal quality.
Support · Health insights
Heart rate and HRV
ARC uses optical PPG sensing for heart-rate and HRV trends. Production accuracy claims will only be published after the relevant validation is complete.
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Fit is part of the measurement
A loose or rotating band can introduce more movement into the optical signal. Keep ARC flat against the skin without making the strap uncomfortably tight.
Exercise is harder than rest
Rapid arm movement, gripping and changing blood flow can make wrist-based heart-rate sensing more difficult during some activities.
HRV needs context
HRV can vary with sleep, training, stress, alcohol, illness, hydration and measurement conditions. Compare similar conditions and longer trends rather than isolated values.
Resting trends
Resting heart-rate and HRV trends are intended for wellness context. They should not be used to diagnose an arrhythmia or other medical condition.
Unexpected readings
Check fit, sensor cleanliness and recent movement. If you have symptoms or a health concern, use appropriate medical care rather than relying on ARC to evaluate it.
Related help
Need help with your specific ARC?
Contact [email protected] with the relevant order number and a clear description of the issue. Never send passwords, one-time codes or reusable sign-in links.