What stimulates the body to breathe?

As a respiratory physiologist, I can explain that the body's drive to breathe is primarily regulated by the levels of certain gases in the blood, particularly carbon dioxide (CO2) and oxygen (O2). The central chemoreceptors, located in the brainstem, are sensitive to changes in the pH of the blood, which is influenced by the levels of CO2. When CO2 levels rise, it leads to a decrease in blood pH, which in turn stimulates the respiratory center to increase the rate and depth of respirations to remove excess CO2 and restore the pH balance. In addition to the central chemoreceptors, there are also peripheral chemoreceptors located in the aortic arch and the carotid arteries. These receptors are more sensitive to changes in oxygen levels. When oxygen levels drop, these receptors send signals to the respiratory center, prompting an increase in the rate and depth of breathing to enhance oxygen intake. In summary, the primary stimuli for breathing are the levels of CO2 and O2 in the blood, with CO2 being the more potent stimulus under normal conditions. However, in certain situations, such as high-altitude environments or in patients with certain medical conditions, the stimulus to breathe may shift to be more influenced by low oxygen levels sensed by the peripheral chemoreceptors.

The rise in carbon dioxide stimulates the respiratory center to increase the rate and depth of respirations to remove excess carbon dioxide. ... Therefore, the patient's stimulus to breathe is no longer an increase in carbon dioxide levels, but from a low oxygen level sensed by peripheral chemoreceptors.