Rescue breaths are artificial breaths given to someone who is not breathing by blowing air into the mouth to inflate the lungs. When delivering rescue breaths, exhaled air contains enough oxygen to support life. It is essential to first establish an open airway before giving rescue breaths. Unresponsive people often lose muscle tone, which allows the base of the tongue to relax and block the airway. Moving the jaw forward lifts the tongue away from the back of the throat, unblocking the airway. Using a protective barrier, such as a shield or mask, when giving rescue breaths helps limit exposure to infectious disease.