Final answer:
The respiratory rate during non-REM sleep is regular, reflecting the body's relaxed state with controlled brain wave patterns that govern respiration.
Step-by-step explanation:
The respiratory rate during non-REM (NREM) sleep is generally regular. During NREM sleep, the body enters a state of reduced activity, with decreases in both respiration and heart rate. NREM sleep is characterized by brain wave patterns that decrease in frequency and increase in amplitude, reflecting this state of regularity and relaxation, which includes the respiratory patterns. Ventilation control centers located in the brain ensure that the breathing rate is adequate for the body's current oxygen and carbon dioxide levels.