Physiological challenge: hypoxia at altitude
The ascent to greater heights presents our organism with an enormous physiological challenge. With increasing altitude the barometric pressure and thus also the partial pressure of oxygen (pO2). This condition is known as hypoxia - a lack of oxygen in the tissue. To overcome this challenge, the body activates a complex cascade of adaptation mechanisms.
Acute phase: rapid reaction of the body
Within the first few hours on the mountain, the body reacts with immediate compensatory mechanisms:
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Hyperventilation: The chemoreceptors in the aortic arch and the carotid artery register the falling
pO2
and stimulate the respiratory center in the brain. This leads to an increased breathing rate and depth in order to maximize oxygen uptake in the lungs. - Cardiac response: Cardiac output is increased by increasing the heart rate to transport circulating oxygen to peripheral tissues more quickly.
- Fluid shift: The body shifts water from the intravascular (blood plasma) into the extravascular spacewhich leads to a temporary hemoconcentration and increases the relative concentration of erythrocytes (red blood cells).
Acclimatization: long-term structural adjustments
After a few days the acclimatizationa profound physiological physiological restructuring:
- Erythropoiesis: In response to hypoxia, the kidneys release an increased amount of the hormone erythropoietin (EPO) in response to hypoxia. This stimulates haematopoiesis in the bone marrow, which leads to increased production of erythrocytes cells. An increase in the haematocrit value and the haemoglobin concentration improves the oxygen transport capacity of the blood significantly.
- Angiogenesis: In the muscle tissue capillarization - the formation of new capillaries. This shortens the diffusion distance for oxygen between the blood vessels and the myocytes. myocytes (muscle cells).
- Cellular level: The density of mitochondriathe "power plants" of the cells, increases. In addition, the efficiency of oxygen extraction from the blood is improved, resulting in optimized aerobic energy production is made possible.
These adjustments are crucial for performance. A careful acclimatization strategy minimizes the risk of acute altitude sickness and allows the body to take full advantage of the physiological benefits of altitude acclimatization.
Sleep in the mountains - Why night-time regeneration works differently at 2,000 meters
The influence of altitude on sleep
Sleep is one of the most important regeneration phases for mountaineers. However, sleep patterns change significantly at higher altitudes. Hypoxia leads to more frequent wake-up reactions, a reduced proportion of deep sleep and sometimes even to periodic breathing during the night. These factors can significantly impair physical and mental recovery.
Strategies for better sleep in alpine regions
Good sleep hygiene is therefore particularly important: adequate fluid, meal and micronutrient intake before sleep, sufficient warm clothing and avoiding alcohol and caffeine. Gradual acclimatization also reduces the likelihood of sleep disorders. If you make sure you get sufficient, high-quality sleep, you create the basis for better regeneration, a strong immune system and sustained performance in the mountains.
Author: Laura Bahmann
Sources:
- West, J. B. (2012). High-Altitude Medicine and Physiology. Oxford University Press.
- Levine, B. D., & Stray-Gundersen, J. (1997). "Living high-training low": effect of altitude acclimatization with intermittent hypoxic exposure on training and athletic performance. Journal of Applied Physiology, 83(1), 102-112.
- Pugh, L. G. C. E. (1962). Physiological and medical aspects of the 1960-61 Himalayan Scientific and Mountaineering Expedition. British Medical Journal, 2(5318), 1362.
