Which term refers to the change in breathing rate during sleep?

The term that refers to a change in breathing rate during sleep is bradypnea. This term specifically denotes an abnormally slow breathing rate, which can occur during various stages of sleep. During sleep, particularly in deep sleep, the body naturally lowers its metabolic demands leading to a decrease in respiratory rate, which might result in bradypnea for some individuals.

In contrast, tachypnea refers to an abnormally rapid breathing rate, which is typically observed in conditions like anxiety, respiratory distress, or fever. Hyperventilation is characterized by an increased rate of breathing that leads to a decrease in carbon dioxide levels in the blood, often resulting from panic or anxiety attacks rather than a change during sleep. Apnea is the term for a temporary cessation of breathing, which can occur during sleep but does not describe the overall change in breathing rate.

Thus, bradypnea is the most accurate answer in the context of a change in breathing rate specifically during sleep.