Question

During high-intensity exercise, why does arterial P_CO2 decrease beyond its usual set point?

Group of answer choices

Arterial P_O2 is reduced during high intensity exercise, which stimulates chemoreceptors to increase ventilation beyond current CO₂ production.

During high intensity exercise, the blood becomes more alkaline, which leads to more CO₂ being converted to H⁺ and bicarbonate.

Anaerobic metabolism does not produce CO₂.

Acidic by-products of anaerobic metabolism decrease plasma pH, which stimulates central chemoreceptors to increase ventilation beyond current CO₂ production.

Answer 1

Option last is the correct answer.

During intense exercise the oxygen demand of body is very high. In absence of sufficient oxygen anaerobic respiration takes place to meet the energy requirement of the body. Anaerobic respiration leads to production of lactic acid which decreases the pH of the blood which stimulate chemoreceptors to hypeventilate beyond current CO2 production.

Note: increased level of CO2 in blood increases acidity as CO2 reacts with water to form carbonic acid.