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  2. Breathing - Wikipedia

    en.wikipedia.org/wiki/Breathing

    Breathing (spiration [1] or ventilation) is the rhythmical process of moving air into and out of the lungs to facilitate gas exchange with the internal environment, mostly to flush out carbon dioxide and bring in oxygen. All aerobic creatures need oxygen for cellular respiration, which extracts energy from the reaction of oxygen with molecules ...

  3. Effects of high altitude on humans - Wikipedia

    en.wikipedia.org/wiki/Effects_of_high_altitude...

    People who are predisposed to develop high-altitude pulmonary edema may present a reduction in urine production before respiratory symptoms become apparent. [ 15 ] Humans have survived for two years at 5,950 m (19,520 ft, 475 millibars of atmospheric pressure), which is the highest recorded permanently tolerable altitude; the highest permanent ...

  4. High altitude breathing apparatus - Wikipedia

    en.wikipedia.org/wiki/High_altitude_breathing...

    High altitude breathing apparatus is a breathing apparatus which allows a person to breathe more effectively at an altitude where the partial pressure of oxygen in the ambient atmospheric air is insufficient for the task or to sustain consciousness or human life over the long or short term.

  5. Oxygen mask - Wikipedia

    en.wikipedia.org/wiki/Oxygen_mask

    An early 1919 high-altitude oxygen system used a vacuum flask of liquid oxygen to supply two people for one hour at 15,000 ft (4,600 m).

  6. Armstrong limit - Wikipedia

    en.wikipedia.org/wiki/Armstrong_limit

    Well below the Armstrong limit, humans typically require supplemental oxygen in order to avoid hypoxia. For most people, this is typically needed at altitudes above 4,500 m (15,000 ft). Commercial jetliners are required to maintain cabin pressurization at an equivalent effective cabin altitude of not greater than 2,400 m (8,000 ft).

  7. Breathing gas - Wikipedia

    en.wikipedia.org/wiki/Breathing_gas

    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 ...

  8. Work of breathing - Wikipedia

    en.wikipedia.org/wiki/Work_of_breathing

    The normal relaxed state of the lung and chest is partially empty. Further exhalation requires muscular work. Inhalation is an active process requiring work. [4] Some of this work is to overcome frictional resistance to flow, and part is used to deform elastic tissues, and is stored as potential energy, which is recovered during the passive process of exhalation, Tidal breathing is breathing ...

  9. Liquid breathing - Wikipedia

    en.wikipedia.org/wiki/Liquid_breathing

    Liquid breathing is a form of respiration in which a normally air-breathing organism breathes an oxygen-rich liquid which is capable of CO 2 gas exchange (such as a perfluorocarbon). [ 1 ] The liquid involved requires certain physical properties, such as respiratory gas solubility, density, viscosity, vapor pressure and lipid solubility, which ...