In medicine,<unk>  (also known as respiratory depression) occurs when ventilation is inadequate (hypo means "below") to perform needed gas exchange. It generally causes an increased concentration of carbon dioxide (hypercapnia) and respiratory acidosis. It can be caused by medical conditions, by holding one's breath, or by drugs, typically when taken in overdose.<unk>  may be dangerous for those with sleep apnea.
Hypoventilation
Hyperventilation
Permissive hypercapnia
Cerebral hypoxia
Hypocapnia
Respiratory losses
Hypercapnia
Shallow breathing