Question

When mountain climbers scale Mt. Everest, they usually bring tanks of oxygen to breathe from; however, at 29,000 feet the oxygen arrives in their mask at the surrounding atmospheric pressure, which is substantially lower than the atmospheric pressure at sea level (Table 16.5). Why does breathing an oxygen-enriched gas mixture help keep a person alive at high altitude, when the pressure is so low overall? Aside from the question of altitude sickness, is it possible to tell if you're getting enough oxygen when you're at sea level?

Answer 1

Altitude refers to the regions of earth surface that are high above the mean sea level which is generally defined to begin at 2,400 meters above the sea level. At higher altitudes, the atmospheric pressure is lower than at the sea level. The percentage of oxygen in the air doesn't change significantly with altitude up to about 85 km from the earth. At sea level, oxygen comprises of about 23% of the air similar to the percentage found at high altitudes , the difference is that at higher altitudes the pressure the entire atmosphere decreases so there is less air to breath At the summit of Mount Everest there will be approximately 33% of oxygen that is available at the sea level however the oxygen delivered to the blood stream is less in other words there is a decrease in the pressure of air which makes only fewer molecules available for the purpose. The physiological process by which the body adjusts to the altitude is known as acclimatization. The first and foremost change that occurs is the increase in the frequency and depth of breathing, the heart pups faster and the blood pressure rises, the red blood cell production is increased resulting in an increased concentration of hemoglobin to pick up more oxygen and transport it around the body .These mechanisms help the body to deliver enough oxygen to all the cells despite low oxygen levels