Search results
Results from the WOW.Com Content Network
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.
By contrast, the women of long-resident, high-altitude populations are known to give birth to heavier-weight infants than women of the lowland. This is particularly true among Tibetan babies, whose average birth weight is 294–650g (~470) g heavier than the surrounding Chinese population, and their blood-oxygen level is considerably higher. [24]
In the region from sea level to around 3,000 m (10,000 ft), known as the physiological-efficient zone, oxygen levels are usually high enough for humans to function without supplemental oxygen and altitude decompression sickness is rare. The physiological-deficient zone extends from 3,600 m (12,000 ft) to about 15,000 m (50,000 ft).
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.
An aquatic system lacking dissolved oxygen (0% saturation) is termed anaerobic, reducing, or anoxic. In water, oxygen levels are approximately 7 ppm or 0.0007% in good quality water, but fluctuate. [5] Many organisms require hypoxic conditions. Oxygen is poisonous to anaerobic bacteria for example. [3]
When examining blood oxygen levels, scientists found that lower oxygen levels during sleep was correlated with both higher hippocampal volume and white matter hyperintensities, or areas of brain ...
An Alpine chough in flight at 3,901 m (12,799 ft). Organisms can live at high altitude, either on land, in water, or while flying.Decreased oxygen availability and decreased temperature make life at such altitudes challenging, though many species have been successfully adapted via considerable physiological changes.
Air pressure actually decreases exponentially with altitude, for altitudes up to around 70 km (43 mi; 230,000 ft), dropping by half every 5.6 km (18,000 ft), or by a factor of 1/e ≈ 0.368 every 7.64 km (25,100 ft), which is called the scale height. However, the atmosphere is more accurately modeled with a customized equation for each layer ...