Cardiio brands itself as “A simple app to measure your heart rate.” Without getting into the fussiness or technicalities, it may be best to download and use the app for that simple purpose. It is available for free in the App Store. It is not intended to diagnose, treat or prevent any condition. The developers have made it clear the app is not a clinical pulse oximeter and is not FDA approved.
Cardiio works by using your smartphone’s camera to capture slight changes in light. The design was originally developed at the Massachusetts Institute of Technology (MIT). It is an app developed by Ph.D. scientists/engineers to help monitor wellness through your heart rate.