You only need to be connected to the app while you're actively using and interacting with the app. You do not have to keep the app open or stay connected to your phone while a cooling or warming session is in progress. You do not need to be connected to the app to: continue cooling or warming after starting a session in the app start a session using the buttons on your Wave stop a session using the buttons on your Wave start a preset session using the buttons on your Wave adjust the temperature level with the buttons on the Wave You do need to be connected to the app to: start a cooling or warming session from your Last Used, Recommended, or Explore Sessions edit, save, or rename a session reprogram your button presets explore sessions view your usage history adjust your LED brightness