Evidence of Limonene in Breath Samples in Men from the World’s Highest City

A study to measure the composition of exhaled air was carried out in subjects living in the highest city in the world: La Rinconada in Peru. People living at high altitude have a strongly disturbed metabolism and have to deal with major physiological disturbances. It is very likely that these subjects develop a disturbance of their redox system. It was therefore undertaken to study their ability to resist oxidative stress by measuring markers in the exhaled air. The traditional biomarkers encountered in this case are the alkanes resulting from the oxidative degradation of unsaturated fatty acids. The breath was collected on carbotrap tubes thanks to the Exp'Air sampling system. The analyses were carried out by GC-MS. In addition to some alkanes, witnesses of the particular conditions of their exposure to the low quantities of oxygen present in the air, it was discovered surprisingly the presence of a compound rarely detected in the exhaled air, limonene. Hypotheses are presented but no certainty exists as to the origin of this compound in the breath. Further studies are underway to determine the conditions and circumstances of occurrence of limonene in the exhaled air of these subjects chronically exposed to hypoxia.