Phone to Ring Proximity: General Guidelines
Once you've paired your ring with your phone, it's fine to leave your phone (i.e. going for a run). As a stand-alone device, the ring can store data for up to 6 weeks without syncing with the Oura app. The ring will also collect data when airplane mode is enabled.
Once your phone is in range again (with the Oura app running and your device's Bluetooth enabled), the ring will upload the data to your phone automatically.