1) Acapnia 2) Physiological condition 3) Physiological state 1) Acapnia 
Hypocapnia or hypocapnea also known as hypocarbia, sometimes incorrectly called acapnia, is a state of reduced carbon dioxide in the blood. Hypocapnia usually results from deep or rapid breathing, known as hyperventilation. Hypocapnia is the opposite of hypercapnia. ==Effects== Even when marked, hypocapnia is normally well tolerated. However, hypo...
<biochemistry, physiology> Deficiency of carbon dioxide in the blood, resulting from hyperventilation and eventually leading to alkalosis. ... (12 Dec 1998) ... 
(hi″po-kap´ne-ә) deficiency of carbon dioxide in the blood; it results from hyperventilation and eventually leads to alkalosis. Called also hypocarbia. adj., hypocap´nic., adj.
Type: Term Pronunciation: hī′pō-kap′nē-ă Definitions: 1. Abnormally decreased arterial carbon dioxide tension. Synonyms: hypocarbia
Hypocapnia: Less than the normal level of carbon dioxide in the blood. Hypoapnia is the opposite of hypercapnia. The origin of the suffix '-capnia' is curious. It comes from the Greek 'kapnos' referring to carbon dioxide which is a principal part of smoke.
[n] - a state in which the level of carbon dioxide in the blood is lower than normal
hypocapnia Abnormally decreased arterial carbon dioxide tension; hypocarbia.