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The human body can perform best at sea level, [7] where the atmospheric pressure is 101,325 Pa or 1013.25 millibars (or 1 atm, by definition). The concentration of oxygen (O 2) in sea-level air is 20.9%, so the partial pressure of O 2 (pO 2) is 21.136 kilopascals (158.53 mmHg).
Bottled oxygen, more broadly known as high pressure compressed oxygen, medical oxygen, and aviator's oxygen, is oxygen in small, portable, high-pressure storage cylinders. For aviation, the weight of the cylinder is usually not critical, and the choice of material may be affected by economic considerations such as purchase price and useful ...
A breathing gas is a mixture of gaseous chemical elements and compounds used for respiration. Air is the most common and only natural breathing gas. Other mixtures of gases, or pure oxygen, are also used in breathing equipment and enclosed habitats such as scuba equipment, surface supplied diving equipment, recompression chambers, high-altitude mountaineering, high-flying aircraft, submarines ...
Highlanders are thus constantly exposed to a low oxygen environment, yet they live without any debilitating problems. [23] One of the best-documented effects of high altitude on non-adapted women is a progressive reduction in birth weight. By contrast, the women of long-resident, high-altitude populations are known to give birth to heavier ...
Air is liquefied by the Linde process, in which air is alternately compressed, cooled, and expanded, each expansion results in a considerable reduction in temperature. With the lower temperature the molecules move more slowly and occupy less space, so the air changes phase to become liquid.
The air is so rarefied that an individual molecule (of oxygen, for example) travels an average of 1 kilometre (0.62 mi; 3300 ft) between collisions with other molecules. [27] Although the thermosphere has a high proportion of molecules with high energy, it would not feel hot to a human in direct contact, because its density is too low to ...
Atmospheric nitrogen has a partial pressure of approximately 0.78 bar at sea level. Air in the alveoli of the lungs is diluted by saturated water vapour (H 2 O) and carbon dioxide (CO 2), a metabolic product given off by the blood, and contains less oxygen (O 2) than atmospheric air as some of it is taken up by the blood for metabolic use. The ...
Mountaineering, mountain climbing, or alpinism [1] is a set of outdoor activities that involves ascending mountains. Mountaineering-related activities include traditional outdoor climbing , skiing , and traversing via ferratas that have become sports in their own right.