Lack of acclimatization to chronic hypoxia in humans in the Antarctica

Abstract

The study was carried out at Concordia Station (Antarctic Plateau). The aim was to investigate the respiratory and haematological responses to hypoxia in healthy subjects living at constant altitude. Thirteen men and women (34.1 ± 3.1 years) were exposed for 10 months to hypobaric hypoxia (oxygen level equivalent to 3800 m asl). These unique conditions enable a greater accuracy of monitoring human responses to chronic hypoxia than can be achieved elsewhere. Blood haemoglobin and erythropoietin concentrations were determined at sea level (Pre), and after 3, 7, 20, 90 and 300 days at altitude. Blood gas analysis, base excess and arterial oxygen saturation were measured at Pre, and after 150 and 300 days at altitude. Erythropoietin returned quickly to baseline level after a transient increase in the first days. Blood haemoglobin concentration started increasing at day 7 and remained markedly higher for the entire duration of the mission. At day 150 the blood carbon dioxide partial pressure was markedly reduced, and consequently blood pH remained higher at negative base excess until day 300. The arterial oxygen saturation remained lower than Pre throughout. In conclusion, humans display little capacity of hypoxia acclimatization even after ten months of constant exposure to low oxygen partial pressure.

COVID-19-associated cardiovascular morbidity in older adults: a position paper from the Italian Society of Cardiovascular Researches

“…First, the hypoxia-driven hyperventilation response, mediated by the carotid bodies and aimed at restoring normal oxygenation, necessarily implies excessive washout of carbon dioxide, which shifts the acid-base balance towards alkalosis. Such response has been found in healthy subjects even at moderate altitude for periods of time ranging from few days (Samaja et al 1997) to several months (Porcelli et al 2017). Although often partially compensated by metabolic acidosis, alkalosis of either origin represents a common finding in critically ill patients (Maehle et al 2014;Kreü et al 2017).…”

Factors contribution to oxygen concentration in Qinghai-Tibetan Plateau

“…伴随 着高海拔而来的急性高原病(AMS) [11] 和慢性高原病 (CMS) [19,20] 等对人类适应这一极端环境的能力提出 了巨大的挑战. 一些研究则表明, 即使经过较长时间 的持续暴露, 人类对低氧环境的适应能力仍处于较 低水平 [21,22] . 高海拔地区恶劣的自然环境、欠发达的 基础设施建设水平和医疗卫生体系以及愈来愈多的 人口暴露和人类较低的适应能力, 使得这一区域的 人口环境风险居高不下.…”

Long-Term Environmental Hypoxia Exposure and Haematopoietic Prolyl Hydroxylase-1 Deletion Do Not Impact Experimental Crohn’s Like Ileitis

“…We exposed the mice to environmental hypoxia starting at 5 weeks of age to minimize the risk of early death as a result of weight loss during the acclimatization period. Weight loss has also been described in high altitude mountaineers [ 21 , 22 , 23 , 24 ]. Indeed, all mice housed in hypoxia experienced body weight loss during the first 5 days of the experiment, which was due to loss of appetite and in accordance with previous reports [ 21 , 22 ], while no effect on further weight gain could be observed.…”