Exercise causes the muscle cells to contract faster and require more oxygen to break down glucose for energy. The Association of the British Pharmaceutical Industry, or ABPI, states that to obtain oxygen, the breathing rate and volume increase rapidly, which also helps to remove the carbon dioxide produced.
If aerobic respiration does not provide enough oxygen for energy, the ABPI explains that the muscles start the process of anaerobic respiration. Instead of producing carbon dioxide, anaerobic respiration produces lactic acid. To break lactic acid down into carbon dioxide and water, the body requires more oxygen, causing the breathing rate to remain high even after stopping the exercise.
Exercising continuously causes the resting breathing rate to slow, according to the ABPI. As the body becomes more fit, the lungs get bigger, more efficient and increase blood supply, resulting in faster recovery times. Some athletes choose to exercise at higher altitudes that have a similar affect on breathing rates, hoping for an advantage when they compete at sea level.
The breathing rate is automatically controlled through voluntary and involuntary systems, according to the University of New Mexico. The respiratory center measures the balance of carbon dioxide and oxygen in the blood, and an excess of carbon dioxide creates a signal to increase the breathing rate. However, singers, musicians and athletes all demonstrate voluntary control over their breathing for short periods of time.