When there is a chronic (long term) increase in blood carbon dioxide, the brain starts to ignore the oxygen level and monitors the blood carbon dioxide level to determine when to take the next breath.
Kui on krooniline (pikaajaline) tõus veres süsihappegaasi, aju hakkab ignoreerima hapniku tase ja jälgib veres süsihappegaasi taset kindlaks teha, millal teha järgmine hingeõhk.