The cardio-respiratory system works together to get oxygen to the working muscles and remove carbon dioxide from the body.
During exercise the muscles need more oxygen in order to contract and they produce more carbon dioxide as a waste product. To meet this increased demand by the muscles, the following happens:
Breathing depth (tidal volume) and rate increase – this gets more oxygen into the lungs and removes more carbon dioxide out of the lungs.
The graph shows that as a person goes from rest to exercise, their tidal volume increases.
Heart rate increases – this increases the rate that oxygen is transported from the blood to the working muscles and carbon dioxide is transported from the working muscles to the lungs.
This graph indicates the following: