Respiratory Adaptations to Exercise

RESPIRATORY ADAPTATIONS TO EXERCISE

In response to training, athletic performance increases because the cardiovascular and respiratory systems become more efficient at delivering O₂ and picking up CO₂. In most individuals, breathing does not limit performance because breathing can increase to a greater extent than can cardiovascular function.

 After training, vital capacity increases slightly, and residual volume decreases slightly. Tidal volume at rest and during stan-dardized, submaximal exercise (activities normally encountered in everyday life) does not change. At maximal exercise, however, the tidal volume increases. Increased efficiency of the respiratory system in response to training is evident because the respiratory rate at rest or during standardized submaximal exercise in trained individuals is slightly lower; however, at maximal exercise, their respiratory rate is usually increased.

 Minute ventilation is affected by changes in tidal volume and breathing rate. After training, minute ventilation is essentially unchanged or slightly reduced at rest, slightly reduced during stan-dardized submaximal exercise, and greatly increased at maximal exercise. For example, an untrained person with a minute ventila-tion of 120 liters per minute (L/min) can increase his or her minute ventilation to 150 L/min after training. Increases to 180 L/min are typical of highly trained athletes.