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Since 2019, a team of researchers has been interested in the consequences of oxygen restriction on health. Studying in the world’s highest city in Peru, they discovered how hypoxia affects the vascular system.
Do you know hypoxia? This is a deficiency of oxygen in a tissue or organ. An almost banal insufficiency for the inhabitants of Rinconada – an extraordinary town perched at an altitude of 5,300 meters – but which is not without consequences for their health (and yours, if you go skiing soon).
At altitude, arteries and vessels are permanently dilated
To better understand the effects of lack of oxygen on the body of residents, a research team from Inserm, Grenoble Alpes University and Grenoble Alpes University Hospital carried out the investigation in Peru.
During this mission, researchers were interested in the effects of severe hypoxia on the vascular system. They recruited 94 adult people and measured, using imaging techniques and blood samples, “thethe responsiveness of their blood vessels“, that is to say their ability to contract or expand in the face of external stimuli.
More precisely, they measured the reactivity of the vascular system on both large arteries (macrocirculation) and small blood vessels (cutaneous microcirculation) in Peruvian populations living at different altitude levels, including inhabitants of Rinconada .
Result ? In people living at high altitude, that is, those who live permanently in a situation of severe hypoxia, the arteries and vessels were permanently dilated, “thereby decreasing their ability to expand additionally in response to a stimulus“.
“The results obtained demonstrate both a form of adaptation of the organism of these inhabitants to a situation of permanent hypoxia (we also speak of chronic hypoxia) but also the achievement of certain limits of tolerance to severe hypoxia at high altitude, which can lead to health complications (high blood pressure or heart failure)”, reveals the press release from Inserm.
Scientists have also identified a “increase in the inflammatory status of residents with altitude“, and in particular “oxidative stress“, caused by an imbalance between free radicals produced by the cell and antioxidants. Major discoveries, which provide valuable insight into the body’s adaptation mechanisms.
“This study allows us to describe for the first time a cascade of mechanisms present in people experiencing chronic hypoxia, from the inflammatory response to its effects on the vascular system.explains Julien Brugniaux, teacher-researcher at Grenoble Alpes University. “These results allow us more broadly to better understand our body’s reactions to lack of oxygen and in particular the effects of these situations on our vascular functioning.“, he continues.
Thanks to this work, the researchers fulfill their dual objective: to help local populations by offering them appropriate medical care, but also to better understand the mechanisms at work in the event of hypoxia, as is the case in many cardiovascular and respiratory diseases.
Hypoxia, a common phenomenon in the mountains
The higher we go, the more the oxygen supply to our body decreases. The body therefore finds itself exposed to this lack of oxygen from 1500-2000 meters… and the effects on the body do not take long to be felt.
Headaches, fatigue, nausea, vomiting, loss of appetite, irritability, and in more serious cases, shortness of breath can occur, often with effort (during a ski descent, for example).
“Most people can climb up to 1500 to 2000 meters in a day without problems, but about 20% of people who climb up to 2500 meters and 40% of those who climb up to 3000 meters have some form of the altitude sickness (doxygen deficiency felt at high altitude)”, confirms the MSD Manual.
“Symptoms may include shortness of breath, headache and nausea“. Signs that should not be ignored because if you continue to climb, the headache becomes severe and a dry cough, difficulty breathing, impaired consciousness and vomiting can be added.
In the event of hypoxia, how to react? “A descent to a lower altitude becomes urgent at this point.” estimates the doctor. “Otherwise, very serious accidents could result such as pulmonary edemafatal within a few hours, or a coma”. Medication and/or oxygen may also be necessary.
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