One in three people climbing Everest suffers from cardiac arrhythmias. The body’s adaptation abilities at high altitude can favor this phenomenon, according to a study from the University of Bern.
Until now, small studies carried out at moderate altitudes indicated a more frequent occurrence of cardiac arrhythmias, the University of Bern said in a press release. In the current study, researchers from the University Cardiology Clinic of the Island Hospital and Nepalese scientists looked at the question at very high altitudes.
They equipped 41 healthy volunteers with portable electrocardiograms after assessing the condition of their hearts: 34 of the study participants reached the base camp, 32 the South Col at 7900 meters above sea level and 14 the summit of Mount Everest, the highest mountain in the world, at 8848 meters above sea level.
Results: more than a third of them had heart rhythm disturbances during the ascent to the base camp at 5300 meters, which was not the case below 1500 meters. It was about slow disturbances and interruptions. However, tachycardias have also been observed.
None of these disorders, however, were clinically serious. Notably, the majority appeared below 7,300 meters, where most climbers did not use bottled oxygen.
According to the conclusions of doctors, the disorders are due to the body’s adaptation mechanisms to the thin air at high altitude. Breathing patterns during sleep as well as salt metabolism play an important role, according to this work published in the American journal JAMA Cardiology.
Future studies will need to take a closer look at the possible effects of these heart rhythm disturbances, to find out whether they constitute an additional and so far underestimated risk of high altitude mountaineering, writes the university.
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