A significant aspect of this part of diagnosis is the breathing of the patient and the sound of the voice. A loud assertive voice suggests a yang pattern, while a weak or timid voice suggests the opposite, a yin pattern. Restless and heavy breathing occurs in an excess syndrome whereas shallow breathing is indicative of a deficient condition. Even the sound of a cough gives an indication of the level of phlegm in the lungs, and can be loud and sudden or weak and persistent. From the breath of the patient the doctor can detect heat in the stomach and other conditions associated with chronic bad breath.