Anyone who is considering climbing Mt. Kilimanjaro should have a basic understanding of the body during a High Altitude trek. The higher we walk, the lower the atmospheric pressure becomes. At the summit of Mount Kilimanjaro (5895 m.), the pressure is half of the pressure at sea level. All parts of our body are affected by this loss of pressure, like a plastic bottle that expands when you take it on an airplane. Our cells, tissues, organs, and muscles are expanding due to the lower air pressure. Sometimes, the wall of the blood vessels become permeable and liquid plasma passes into the organs, creating edemas (pulmonary edema HAPE, or cerebral edema - HACE).
The ability of our lungs to collect Oxygen is also diminished because the quantity of Oxygen available in a normal breath becomes significantly less than under normal conditions (Sea Level). At an altitude of 2000 m., one can already feel the effects of the altitude during physical efforts. And from 3000 m, 80% of people feel the effects even when resting. The body enters in a state of Hypoxemia (lack of oxygen pressure in the blood), which start off a series of replies from the organism in 3 steps.
During the first step, called Accommodation, the body accelerates the ventilation and the cardiac rhythm. This is a short period where there is no other sign of Acute Mountain Sickness (AMS).
After 24 hours at altitude, the body starts Acclimatization. This is when the kidneys start to produce Erythropoietin (EPO), a hormone that promotes the formation of red blood cells. During this process, it is important to limit physical efforts and respect the levels of acclimatization (increases of no more than 400 meters of elevation between two consecutive nights). Indeed, the reaction of the body will be to breathe faster to collect as much oxygen as possible. However until the red blood cells are operational to transport this oxygen, the body will not recover to normal oxygen saturation in the blood. Furthermore, there is a risk of Hyperventilation that can leads to a reduction of Carbon Dioxide (CO2). CO2 is important in controlling the acidity of the blood, and the body will automatically try to block the reduction of CO2 by obstructing respiration, thus creating short apnea in order to stabilize the level of CO2. The kidneys, already solicited to produce the EPO hormone, will also work to stabilize the acidity of the blood, by evacuating any excess bicarbonate. For this reason people with kidney failure need to be particularly cautious when at high altitudes. During the acclimatization phase, the body needs all the available oxygen to go to the main organs (brain, liver and heart). However, during physical activity the muscles also need oxygen. Therefore, people that are very physically fit will usually suffer more from the lack of oxygen as their muscles are bigger and will consume more oxygen.
It is only after approximately a week that the new red blood cells are mature enough to start their function of carrying oxygen to the cells. After about 3 weeks spent in high altitude, we can obtain a level of Acclimation where the body recovers the same physical conditions as at Sea level. Trekking on Mount Kilimanjaro is done in 5 to 9 days, so there is not sufficient time to arrive to a good level of acclimation. However, sleeping a few nights at 2500-3000m before the trek will considerably help the acclimatization.
People that have never been at high altitudes or that have had problems with acclimatization in the past should consider a 4 day acclimatization trek on Mount Meru (4565 m) before attempting the higher sister, Mount Kilimanjaro.
The ability of our lungs to collect Oxygen is also diminished because the quantity of Oxygen available in a normal breath becomes significantly less than under normal conditions (Sea Level). At an altitude of 2000 m., one can already feel the effects of the altitude during physical efforts. And from 3000 m, 80% of people feel the effects even when resting. The body enters in a state of Hypoxemia (lack of oxygen pressure in the blood), which start off a series of replies from the organism in 3 steps.
During the first step, called Accommodation, the body accelerates the ventilation and the cardiac rhythm. This is a short period where there is no other sign of Acute Mountain Sickness (AMS).
After 24 hours at altitude, the body starts Acclimatization. This is when the kidneys start to produce Erythropoietin (EPO), a hormone that promotes the formation of red blood cells. During this process, it is important to limit physical efforts and respect the levels of acclimatization (increases of no more than 400 meters of elevation between two consecutive nights). Indeed, the reaction of the body will be to breathe faster to collect as much oxygen as possible. However until the red blood cells are operational to transport this oxygen, the body will not recover to normal oxygen saturation in the blood. Furthermore, there is a risk of Hyperventilation that can leads to a reduction of Carbon Dioxide (CO2). CO2 is important in controlling the acidity of the blood, and the body will automatically try to block the reduction of CO2 by obstructing respiration, thus creating short apnea in order to stabilize the level of CO2. The kidneys, already solicited to produce the EPO hormone, will also work to stabilize the acidity of the blood, by evacuating any excess bicarbonate. For this reason people with kidney failure need to be particularly cautious when at high altitudes. During the acclimatization phase, the body needs all the available oxygen to go to the main organs (brain, liver and heart). However, during physical activity the muscles also need oxygen. Therefore, people that are very physically fit will usually suffer more from the lack of oxygen as their muscles are bigger and will consume more oxygen.
It is only after approximately a week that the new red blood cells are mature enough to start their function of carrying oxygen to the cells. After about 3 weeks spent in high altitude, we can obtain a level of Acclimation where the body recovers the same physical conditions as at Sea level. Trekking on Mount Kilimanjaro is done in 5 to 9 days, so there is not sufficient time to arrive to a good level of acclimation. However, sleeping a few nights at 2500-3000m before the trek will considerably help the acclimatization.
People that have never been at high altitudes or that have had problems with acclimatization in the past should consider a 4 day acclimatization trek on Mount Meru (4565 m) before attempting the higher sister, Mount Kilimanjaro.
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