Essay On Hypoxia

2238 Words 9 Pages
Physiological Effects of Decreased Atmospheric Pressure
At lower altitudes such as sea level, the main stimulation for ventilation is carbon dioxide. (7) At high altitudes, hypoxia stimulates ventilation. (7) However, hypoxia only stimulates ventilation when the partial pressure of inspired oxygen is reduced to roughly 13.3kPa, and is at an altitude of 3000m or more. (7) When the inspired partial pressure of oxygen is 13.3kPa, alveolar oxygen pressure is 8kPa. (7) As hypoxia continues to increase, ventilation rises expodentionally. (7) In the lungs, hypoxia acts as a vasoconstrictor in the pulmonary circulation. (7) The vasoconstriction may help with ventilation and perfusion in the lungs. (7) However, the reflex leads to pulmonary hypertension and is associated with pulmonary edema at high altitudes. (7) In regards to the heart, initially at a high altitude, cardiac output increases in relation to physical activity, but will then settle back to sea level values. (7) As cardiac output increases, there is an increase in heart rate, and a decrease in stroke volume. (7) An individual’s maximum obtainable heart rate
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It also provided a description of the role of ventilatory acclimatization. The purpose of altitude training is to enhance athletic performance. Altitude training is proven to be effective, because as altitude increases and the pressure exerted by oxygen decreases, the partial pressure of gases in the body decrease. This change in pressure elicits physiological changes in the body, such as an increase in red blood cell count. Ventilatory acclimatization is an advantageous adaptation to a change in altitudes by protecting the alveolar partial pressure of oxygen. In sum, altitude training may be highly beneficial to elite athletes, but it does not come without its potentially harmful physiological

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