Question

how does our body adapt to low oxygen availability at high altitude?

Answer 1

at high altitude number of rbcs in our body increase to full fill the demands of tissues and maintain the respiratory rhythm and trap more oxygen in our body .also our external nostrils becomes wider. .

Answer 2

There are two major kinds of environmental stresses at high altitude for humans. First, there are the alternating daily extremes of climate that often range from hot, sunburning days to freezing nights. In addition, winds are often strong and humidity low, resulting in rapid dehydration. Second, the air pressure is lower. This is usually the most significant limiting factor in high mountain regions.


Air pressure
decreases
as altitude
increases

drawing of the earth's surface and the atmosphere above it showing that with increasing distance from the earth, the gas molecules in the atmosphere are farther apart and the air pressure is lower

Click here for more information about the earth's atmosphere

The percentage of oxygen in the air at two miles (3.2 km.) is essentially the same as at sea level (21%). However, the air pressure is 30% lower at the higher altitude due to the fact that the atmosphere is less dense--that is, the air molecules are farther apart.