If prolonged, it may be a sign of hypoxemia or acidosis and needs to be reported. There is an increased ingestion of food that goes far beyond basal and physical activity needs of adults. They need increased calories per unit of body weight because BMR is greater. Because of smaller size, the absolute fluid volume needs are less. If ill, needs change.
Illness increases fluid needs particularly along with fever, vomiting, and diarrhea.
Increased metabolism increases oxygen demand which increases respiratory rate and increases fluid loss so child gets easily dehydrated. With babies, GI problems are also related to air swallowing which increases danger of aspiration. Child needs to be burped frequently to remove swallowed air. Then place on right side or prone. As they mature, it tightens and regurgitation decreases.