Mya is running a marathon. her heartbeat increases. how does the increase in heartbeats assist mya’s respiratory system?

As Mya’s heartbeat increases, the pulse rate and breathing rate will also increase with running or by simply exercising. As the heartbeat speeds up, the arteries expand to send more blood to the muscles and back to the lungs to get more oxygen and to get rid of carbon dioxide. Therefore, the heart rate is tied with breathing and this mechanism is called  "respiratory sinus arrythmia (RSA)".

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