High Plateau Health Journey - Popular Reading on Self-Care

Author: Ning Xuehan, Li Shuping
Publisher:
Publish Date: 2006-10-01
Features: Physical Reactions Upon Arrival at High Altitude
When first arriving at a high-altitude location, such as the Lhasa Airport, the body experiences reactions due to the lower oxygen content in the thin air compared to flatlands. For the same breath taken, the oxygen level in the alveoli decreases accordingly, leading to a drop in blood oxygen levels and disruption of the body's internal homeostasis. At this point, chemical receptors in the body, such as the carotid body, immediately detect the abnormality. On one hand, the body initiates automatic regulatory mechanisms to deepen and accelerate breathing. On the other hand, it transmits information to the central nervous system. Simultaneously, the hypoxic state directly affects the central nervous system. Through neural and humoral regulatory mechanisms, various organs in the body are fully mobilized to intake sufficient oxygen to compensate for the lack of oxygen in the blood. The heart receives the signal, causing the myocardium to contract more strongly and the heart rate to accelerate. The spleen, which stores red blood cells, responds to the hypoxic signal by contracting, increasing the number of red blood cells entering the bloodstream to enhance oxygen transport capacity. Hypoxia also causes blood vessels in major organs such as the heart and brain to dilate, facilitating gas exchange at the cellular level. Meanwhile, blood vessels in secondary organs and peripheral areas constrict to redirect blood flow to vital organs, and so on.
However, changes in breathing can lead to hyperventilation, excessively expelling carbon dioxide from the body, which has an acidic effect. This increases the proportion of alkaline substances, resulting in respiratory alkalosis. In severe cases, it can cause dizziness, nausea, vomiting, and numbness in limbs. The enhancement of respiratory and circulatory functions, combined with peripheral vasoconstriction, may lead to unstable blood pressure. Dilation of intracranial blood vessels increases intracranial pressure, causing headaches. These are physiological responses by the body to maintain homeostasis, or secondary effects if the response is excessive. These effects peak within about 24 hours, earning the condition the name "high-altitude reaction." The respiratory alkalosis caused by hyperventilation requires gradual regulation by the kidneys to restore the body's internal fluid homeostasis.
Typically, within 3 to 7 days, when a new homeostatic balance is established, resting breathing and heart rate responses gradually subside, alkalosis disappears, and headaches alleviate. However, red blood cell and hemoglobin levels continue to rise. At this stage, instead of the spleen contracting, the bone marrow's hematopoietic function is enhanced, allowing the blood to carry more oxygen until the cells' oxygen demand is met.
Following Natural Laws
Since high-altitude reaction is a physiological response to maintain homeostasis, it is best to avoid interfering with this process and allow it to follow its natural course.
1. Avoid Overexertion
Any activity that increases oxygen consumption will exacerbate the imbalance between oxygen supply and demand, delaying the establishment of a new equilibrium. Physical exertion must be increased in a controlled and gradual manner, avoiding sudden or rapid acceleration to prevent oxygen from failing to supply in time, which could lead to a significant "oxygen debt" and worsen the imbalance.
Once, a colleague, who had just reached an altitude of 4,000 meters, excitedly shouted, "4,000 meters is nothing! I didn't feel any reaction at all," when getting off the vehicle. When he saw me collecting snow lotus on a hill 200 meters away, he ran over too, but after only 50 steps, he collapsed to the ground, gasping for breath and groaning, "I can't go on (meaning 'I'm done,' in Shanghai dialect)."