Effects of long-term very high-altitude exposure on cardiopulmonary function of healthy adults in plain areas.

Due to the unique plateau climate, such as low atmospheric pressure, hypoxia, cold, and dryness, people in plain areas will have a series of physiological and pathological changes after entering the plateau. This observational study was designed to assess the effects of long-term very high-altitude (HA) exposure on the cardiopulmonary function of healthy adults in plain areas through cardiopulmonary exercise testing (CPET). We tracked and observed 45 healthy adult men or women from the plain area (Beijing, with an altitude of approximately 40 m). They worked and lived in very HA areas (Lhasa, with an altitude of approximately 3,700 m) for 5 months before returning to plain areas. Participants completed health checkups, including basic physiological indexes, static pulmonary function tests, and CPET at baseline and after very HA exposure. The resulting data showed that after long-term very HA exposure, multiple CPET indicators significantly decreased (p < 0.05), including peak oxygen uptake, anaerobic threshold, peak work rate, oxygen uptake/work rate, peak oxygen uptake/heart rate, oxygen uptake efficiency slope, peak minute ventilation, peak end-expiratory carbon dioxide partial pressure, and peak cardiac output. The minute ventilation/carbon dioxide production slope was significantly higher than that before very HA exposure (p = 0.004). There were no significant changes in static pulmonary function (p > 0.05). In conclusion, long-term very HA exposure can lead to varying degrees of negative effects on cardiopulmonary function (including respiratory, circulatory, and metabolic function decline) in healthy adults in plain areas. The abnormality of related functional indicators may indicate that the body's adaptive compensatory mechanism to the high altitude hypobaric hypoxia environment is decompensated. It is suggested that it is necessary to implement individualized cardiopulmonary rehabilitation training as soon as possible after long-term very HA exposure to mitigate functional decline in individuals.