Final answer:
Acclimatization to high altitude involves physiological changes in the body to compensate for lower oxygen availability. This includes increased erythrocyte production, hyperpnea, and hyperventilation initially, followed by long-term adaptations in lung capacity and cardiovascular function to improve oxygen uptake and delivery.
Step-by-step explanation:
The physiological response to elevated altitude involves several changes in the respiratory and cardiovascular systems, known collectively as acclimatization. Initially, a person exposed to high altitude experiences a decrease in the partial pressure of oxygen, leading to reduced oxygen saturation of hemoglobin and lower tissue oxygen levels, a condition potentially resulting in acute mountain sickness (AMS). To compensate, the body increases the production of erythropoietin (EPO), which stimulates the production of erythrocytes (red blood cells). This results in a greater number of circulating erythrocytes, allowing for improved oxygen transport despite lower oxygen saturation per hemoglobin molecule.
Furthermore, there are immediate changes in breathing patterns. Hyperpnea, an increase in breathing depth and rate, occurs to improve oxygen uptake, while hyperventilation, an increase in breathing that exceeds the metabolic demand for oxygen, helps to maintain oxygen levels at the onset of altitude exposure. In the long term, acclimatization involves physiological modifications such as increased lung capacity and enhanced diffusion capacity, which enable more efficient use of the reduced oxygen available at high altitudes.
The cardiovascular system also adapts by increasing heart rate and stroke volume to boost blood flow and oxygen delivery to tissues. However, caution must be practiced when ascending to high altitudes to allow time for acclimatization and prevent AMS.