Why does pulse (and breathing rate) increase during exercise? (relate to cellular respiration)

During exercise, the rate of breathing increases in order to fulfill the needs of oxygen required by the body for the release pf energy required. The body activity and muscles are in movement and required more energy than at rest. The absorbance of oxygen in to the blood increases which will increase the heart beat and also carbon dioxide starts removing from the blood. the lungs must provide more oxygen to the blood during the exercise.

so as the activity level increases, the demand for oxygen increase which will increase the breathing to take in more oxygen from outside in to lungs so that the lungs pump more oxygen to the hearth which will deliver to the muscles for activity.