Background Data Uploading

I'm working on an app where we want to upload data every 5 minutes or so to a cloud server even if the app is in the background. We're able to receive data from a BLE sensor in the background, but couldn't find anything on uploading the data consistently. We think it should be possible due to products like the Dexcom glucose monitoring system which uploads data from the background every 5 minutes. Any idea on how we'd go about doing this?