When you hold your breath, which of the following blood gas changes first leads to the urge to breathe?
A) rising oxygen
B) falling oxygen
C) rising carbon dioxide
D) falling carbon dioxide

Question

Quizplus · Accepted Answer

The first blood gas change that leads to the urge to breathe is a rising level of carbon dioxide (CO2) in the blood. As CO2 builds up in the bloodstream, it triggers an increase in the acidity of the blood, which stimulates the respiratory center in the brain to initiate breathing. This is why people feel the urge to breathe when holding their breath for an extended period. Rising oxygen levels would actually have the opposite effect and could delay the urge to breathe.

When You Hold Your Breath, Which of the Following Blood