Question

Why does an athlete breathe faster and deeper than usual after finishing the race?

Answer 1

During exercise, when body movements occur we need more energy to perform the task and provide sufficient oxygen for organs to work efficiently. After the task person needs more carbon dioxide to expel out which has been made during the exercise.

Complete answer:
When a person does some vigorous exercise they experience fast respiration rate this happens as the following mechanism occurs inside the body:
For doing the work we need energy and energy is obtained from the glucose or the carbohydrates in the form of ATP which helps us do the essentials
For maintaining the proper functioning of the body organs sufficient amounts of oxygen is needed and during exercise more oxygen, more energy is needed by them.
To accomplish the increased amount of oxygen needed an equal amount of carbon dioxide is produced which is expelled out during the expiration in the respiration process.
This makes the person respire faster and deeper so that each organ gets proper oxygen which is produced by the oxidation of stored food resulting in the production of ATP which gives the energy to perform the body function.

Note: During vigorous exercise, anaerobic respiration takes place which results in lactic acid production and ADP production which generate less energy as compared to ATP causing pain in the muscle, muscle strain can also be formed. Athletes are usually involved in high intensity workouts like running, jumping which causes sudden increase of oxygen demand so that the organs do not collapse so more energy is needed, more ADP and ATP production required.