Since the app queries the coinbase.com API every 15 minutes a working Bluetooth and Internet connection on your phone is required. The built in licensing mechanism will also access the Internet. If your app is still in its trial period a non working connection to the Internet will lead to an error display on your app. In such event, close the app and try again when you are connected again.
Heart rate monitor
Required for the stresslevel indicator
Required to determine the resting heart rate
Required for proper time and date display (12/24 hour and date format)