During cardiorespiratory exercise, what happens to heart rate and breathing rate?

• A. Increases in heart rate and breathing rate
• B. Decreases in heart rate and breathing rate
• C. No change in breathing rate
• D. Only heart rate changes while breathing stays the same

Answer: (A)

During cardiorespiratory exercise, the muscles need more oxygen and produce more carbon dioxide. To meet that demand, the heart speeds up to increase blood flow to working muscles, raising heart rate and cardiac output. At the same time, the breathing rate rises to bring in more oxygen and expel more carbon dioxide. This coordinated boost is driven by the nervous system and chemical signals from exercising muscles and blood, ensuring the lungs and heart work together to support increased activity. So, both heart rate and breathing rate increase.