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Aerospace physiology is the study of the effects of high altitudes on the body, such as different pressures and levels of oxygen. At different altitudes the body may react in different ways, provoking more cardiac output, and producing more erythrocytes. These changes cause more energy waste in the body, causing muscle fatigue, but this varies ...
Room air at altitude can be enriched with oxygen without introducing an unacceptable fire hazard. At an altitude of 8000 m the equivalent altitude in terms of oxygen partial pressure can be reduced to below 4000 m without increasing the fire hazard beyond that of normal sea level atmospheric air.
Atmospheric pressure decreases with altitude while the O 2 fraction remains constant to about 85 km (53 mi), so PO 2 decreases with altitude as well. It is about half of its sea level value at 5,500 m (18,000 ft), the altitude of the Mount Everest base camp, and less than a third at 8,849 m (29,032 ft), the summit of Mount Everest. [8]
An oxygen partial pressure equivalent to sea level can be maintained at an altitude of 10,000 metres (34,000 ft) with 100% oxygen. Above 12,000 metres (40,000 ft), positive pressure breathing with 100% oxygen is essential, as without positive pressure even very short exposures to altitudes above 13,000 metres (43,000 ft) lead to loss of ...
Altitude acclimatization is the process of adjusting to decreasing oxygen levels at higher elevations, in order to avoid altitude sickness. [17] Once above approximately 3,000 metres (10,000 ft) – a pressure of 70 kilopascals (0.69 atm) – most climbers and high-altitude trekkers take the "climb-high, sleep-low" approach.
The percentage of oxygen in the air at high altitudes isn't the issue, since that stays relatively constant at about 21% until about 70,000 feet. The problem is the lack of air pressure.
At 11,900 m (39,000 ft), breathing pure oxygen through an unsealed face mask, one is breathing the same partial pressure of oxygen as one would experience with regular air at around 3,600 m (11,800 ft) above sea level [citation needed]. At higher altitudes, oxygen must be delivered through a sealed mask with increased pressure, to maintain a ...
Tibetans suffer no health problems associated with altitude sickness, but instead produce low levels of blood pigment (haemoglobin) sufficient for less oxygen, more elaborate blood vessels, [21] have lower infant mortality, [22] and are heavier at birth. [23] EPAS1 is useful in high altitudes as a short term adaptive response.