What physiological change occurs during intense exercise related to gas exchange?

• A. Decreased tidal volume
• B. Increased respiratory drive
• C. Reduced cardiac output
• D. Decreased metabolic rate

Answer: (B)

During intense exercise, the body's demand for oxygen increases significantly, and so does the need to remove carbon dioxide. To accommodate these changes, there is an increase in respiratory drive. This physiological response allows for an elevated rate and depth of breathing, known as increased tidal volume and respiratory rate, ensuring that more oxygen is delivered to the working muscles and more carbon dioxide is expelled efficiently.

The increased respiratory drive is mediated by various factors, including increased levels of carbon dioxide in the blood, decreased blood pH, and signals from the working muscles. These changes ensure that gas exchange is optimized to meet the metabolic demands of exercise, facilitating efficient aerobic metabolism and maintaining homeostasis within the body's systems.

In contrast, decreased tidal volume and reduced cardiac output would hinder proper gas exchange by limiting oxygen intake and blood flow, while a decreased metabolic rate would not correspond with the demands of intense exercise, as energy expenditure is significantly heightened during such activities. Therefore, the physiological adaptation of increased respiratory drive is critical for efficient gas exchange during periods of intense physical exertion.