Hypoxia (medicine)

Hypoxia is a condition in which the body or a region of the body is deprived of an adequate <a href="/facts/Oxygen/acyn6o8r">oxygen</a> supply at the <a href="/facts/Tissue_(biology)/H7CpML7A">tissue</a> level. Hypoxia may be classified as either <a href="/facts/Generalized_hypoxia/JWV04G89">generalized</a>, affecting the whole body, or local, affecting a region of the body. Although hypoxia is often a <a href="/facts/Pathological/U9b18LJG">pathological</a> condition, variations in <a href="/facts/Arterial/Y1Yj0jat">arterial</a> oxygen concentrations can be part of the normal <a href="/facts/Physiology/fh25y2pQ">physiology</a>, for example, during strenuous <a href="/facts/Physical_exercise/egYQjt8A">physical exercise</a>.
Hypoxia differs from <a href="/facts/Hypoxemia/n1cqE0JW">hypoxemia</a> and anoxemia, in that hypoxia refers to a state in which oxygen present in a tissue or the whole body is insufficient, whereas hypoxemia and anoxemia refer specifically to states that have low or no <a href="/facts/Oxygen_saturation_(medicine)/9cfum2Yl">oxygen in the blood</a>. Hypoxia in which there is complete absence of oxygen supply is referred to as anoxia.
Hypoxia can be due to external causes, when the breathing gas is hypoxic, or internal causes, such as reduced effectiveness of gas transfer in the lungs, reduced capacity of the blood to carry oxygen, compromised general or local <a href="/facts/Perfusion/EFVLNUTg">perfusion</a>, or inability of the affected tissues to extract oxygen from, or metabolically process, an adequate supply of oxygen from an adequately oxygenated blood supply.
Generalized hypoxia occurs in healthy people when they ascend to <a href="/facts/High_altitude/B5eNVurK">high altitude</a>, where it causes <a href="/facts/Altitude_sickness/DPNTnljN">altitude sickness</a> leading to potentially fatal complications: <a href="/facts/High_altitude_pulmonary_edema/VekkJrQS">high altitude pulmonary edema</a> (<a href="/facts/HAPE/VekkJrQS">HAPE</a>) and <a href="/facts/High_altitude_cerebral_edema/ueHcXlEr">high altitude cerebral edema</a> (<a href="/facts/HACE/ueHcXlEr">HACE</a>). Hypoxia also occurs in healthy individuals when breathing inappropriate mixtures of gases with a low oxygen content, e.g., while <a href="/facts/Underwater_diving/yhjLjF1H">diving underwater</a>, especially when using malfunctioning closed-circuit <a href="/facts/Diving_rebreather/LmuCq5LB">rebreather</a> systems that control the amount of oxygen in the supplied air. Mild, non-damaging <a href="/facts/Intermittent_hypoxia/7zbG7XXC">intermittent hypoxia</a> is used intentionally during <a href="/facts/Altitude_training/hrL5L7Ff">altitude training</a> to develop an athletic performance adaptation at both the systemic and cellular level.
Hypoxia is a common <a href="/facts/Complication_(medicine)/uJHvzqUt">complication</a> of <a href="/facts/Preterm_birth/szMos8tu">preterm birth</a> in newborn infants. Because the <a href="/facts/Lung/gTWXI6Fj">lungs</a> develop late in <a href="/facts/Pregnancy/vEKYGpep">pregnancy</a>, premature infants frequently possess underdeveloped lungs. To improve blood oxygenation, infants at risk of hypoxia may be placed inside <a href="/facts/Incubator_(neonatal)/XvQ9LaM2">incubators</a> that provide warmth, <a href="/facts/Humidity/Nwb28VlT">humidity</a>, and supplemental oxygen. More serious cases are treated with <a href="/facts/Continuous_positive_airway_pressure/f3TobY3a">continuous positive airway pressure</a> (CPAP).

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Hypoxia (medicine)