Final answer:
Exercise significantly increases the breathing rate through a complex interaction of psychological, motor neuron, and proprioceptive stimuli, and even after exercise, breathing rate remains high to fulfill the oxygen debt created by the muscular activity.
Step-by-step explanation:
Exercise impacts breathing rate by triggering an increase in ventilation before oxygen levels in muscle tissues drop, indicating complex neural mechanisms at play rather than just changes in oxygen and carbon dioxide levels.
There are three primary neural mechanisms responsible for increased respiration during exercise: psychological stimulus, motor neuron activation, and proprioceptor activation. These together cause an increase in the depth and rate of breathing, known as hyperpnea. This response begins at the onset of exercise due to a psychological decision to engage in physical activity and the stimulation of the respiratory centers in the brain through motor neuron activation of skeletal muscles and proprioceptors in muscles, joints, and tendons.
After intense physical activity, the body experiences an oxygen debt, needing more oxygen to replenish ATP and creatine phosphate levels, convert lactic acid to pyruvic acid, and in the liver, convert lactic acid into glucose or glycogen. Consequently, breathing rate remains elevated post-exercise until this oxygen debt is fulfilled.