What is the normal adult range for respiratory rate?

• A. 8-12 breaths per minute
• B. 12-20 breaths per minute
• C. 20-24 breaths per minute
• D. 24-28 breaths per minute

Answer: (B)

The main idea here is the normal resting breathing rate for a healthy adult. At rest, adults typically breathe about 12 to 20 times per minute. This range reflects normal brainstem control of breathing in response to CO2 and O2 levels. Rates that are lower than this can indicate bradypnea (slower breathing often due to sleep, medications, or CNS issues), while rates higher than this can indicate tachypnea (faster breathing seen with fever, anxiety, hypoxia, or metabolic disturbances). The range 12–20 is the standard reference, so it best fits what is considered normal for resting adults. The other ranges either fall outside normal at rest or exclude part of the typical range, making them less accurate as the normal adult reference.