High altitude medicine & biology最新文献

Femling, Jon K., Peter S. Figueiredo, Aaron J. Reilly, Jason D. Williams, Trevor J. Mayschak, Erik R. Swenson, Steven D. Landspurg, and Beth A. Beidleman. Does prior respiratory infection increase the risk of high-altitude pulmonary and cerebral edema? A case report. High Alt Med Biol. 26:411-415, 2025.-Inadequate time to acclimatize to the lower partial pressure of oxygen at high altitude (HA) can result in one or more forms of acute altitude illness: acute mountain sickness (AMS), high-altitude pulmonary edema (HAPE), and high-altitude cerebral edema (HACE). AMS is common while HAPE and HACE are exceptionally rare, particularly below 4,000 m. Severe AMS can be debilitating while both HAPE and HACE are potentially deadly if untreated. Cases of HAPE at altitudes <4,000 m have been linked to a preceding, or concurrent, respiratory infection (RI), which may augment susceptibility. This case report details a timeline of continuous physiological monitoring, including heart rate and peripheral oxygen saturation, during active ascent and 42-hour exposure to 3,600 m from an individual diagnosed with HAPE/HACE. The case occurred during a military research study providing a homogenous cohort (n = 37) to compare data. Nocturnal oxygen saturation was poor and deteriorated during the stay. The case reported the most severe AMS symptoms on surveys without vocalized complaints. The case presented the classical symptoms of HACE (ataxia and confusion) by the second morning at HA. An underlying RI was discovered that may have increased his susceptibility to HAPE, and subsequently to HACE, at relatively low altitude.

Burtscher, Martin.V̇O₂max, an important determinant of success when climbing high mountains. High Alt Med Biol. 26:382-384, 2025.-Trekking and climbing at high altitudes without the use of supplemental oxygen require high baseline aerobic performance, i.e., maximal oxygen consumption (V̇O₂max), primarily due to the loss of V̇O₂max with increasing altitude. Thus, basic individual performance (at low altitude) becomes particularly important. This fact is often underestimated, which may fail to reach the summit and could be associated with increased risks of accidents and emergencies. However, timely training preparation and aligning the planned mountaineering goal to individual performance can reduce risk and disappointment on the mountain.

Ni, Zhexin, Yongqiang Zhou, Mingyang Chang, Tiantian Xia, Wei Zhou, and Yue Gao. High-altitude impacts on gut microbiota: Accelerated aging and the urgency for targeted health interventions. High Alt Med Biol. 26:416-423, 2025.-The human gut microbiota is integral to the aging process, and its composition is notably influenced by the unique environmental pressures of high-altitude plateaus, characterized by hypobaric and hypoxic conditions. This study explores the correlation between physiological aging and gut microbiota among high-altitude plateau inhabitants, an essential aspect of health preservation in such regions. We conducted a metagenomic analysis of fecal samples from 105 individuals who migrated to high-altitude areas before the age of 20. Our results demonstrate that advancing age and prolonged high-altitude living significantly modify the gut microbiota, evidenced by reduced diversity and an elevated Firmicutes to Bacteroidetes (F/B) ratio in older subjects. Notably, the abundance of the anti-aging bacterium Akkermansia muciniphila (A. muciniphila) inversely correlates with age, showing a significant decline post the age of 25. A comparative analysis of 2,007 individuals from lower altitudes revealed a similar negative correlation between A. muciniphila and age, with a decline evident from age 38. These findings indicate that the high-altitude plateau environment may accelerate the decline of A. muciniphila by 10 years, underscoring the need for targeted health strategies for high-altitude populations.

Zhang, Lei, Er-Chao Feng, Ji Cang, and Qing De. A case of high-altitude renal syndrome mainly manifested as IgA nephropathy. High Alt Med Biol. 26:408-410, 2025.-This article reports a case of a 30-year-old male patient with "low back pain for 1 year, aggravated for 2 months." Laboratory and imaging examinations, as well as renal biopsy pathological analysis, were carried out. The patient was diagnosed with high-altitude renal syndrome complicated by IgA nephropathy. After treatment with optimized supportive therapy combined with specific drugs for high-altitude diseases, the patient's condition improved significantly. This case provides a reference for the diagnosis and treatment of similar cases.

Baquerizo-Sedano, Luis, José Augusto Chaquila, Juan Pablo Aparco, Carlos Torres Salinas, Orison O. Woolcott, and Pedro González-Muniesa. Extreme variability of anemia prevalence in peruvian children based on different altitude correction factors: A cross-sectional study. High Alt Med Biol. 26:374-381, 2025. Objetives: Higher erythrocytosis is the main hematological adaptation to altitude. Consequently, several correction factors have been proposed to diagnose anemia in children at high altitude. We compared the anemia prevalence in Peruvian children aged 6-59 months living at different altitudes according to several published correction factors to adjust hemoglobin for altitude. Methods: Data were collected from 578,576 children in the Nutritional Surveillance System in Peru in 2020. Anemia prevalence was estimated by altitude every 1,000 m, using four different adjustment criteria, including the recent adjustment proposal from the World Health Organization. Results: The total prevalence of anemia varied substantially (from 3.2% to 33.7%) depending on the adjustment criteria used. Without correction factors, the highest proportion of anemia was observed in the lowest altitude range. However, this result was no longer observed when the adjustment factors were used. For ranges above 3,000 m, moderate anemia occurred with a higher prevalence when using two different correction factors but not others or without adjustment. Conclusions: Our findings reveal substantial changes in anemia prevalence among Peruvian children under 5 years of age depending on the adjustment factors for hemoglobin used. More research is needed to properly diagnose anemia in children at high elevations.

Manferdelli, Giorgio, Marc M. Berger, and Andrew M. Luks. Ignoble gas: The questionable role of xenon in rapid ascents of Mount Everest. High Alt Med Biol. 26:339-346, 2025.-Beyond the logistical, technical, and physiological challenges associated with climbing extremely high mountains such as Mount Everest, an important feature of such expeditions is their long duration. Among the strategies used in recent years to reduce expedition duration, one particularly novel approach was implemented during Everest expeditions in 2024 and 2025-inhalation of the noble gas xenon prior to the expeditions. Despite the tremendous attention this approach received in the media, significant questions remain as to whether it is truly effective at improving acclimatization and shortening the duration of expeditions. This review examines this issue in greater detail. After providing background information on xenon, the review examines potential rationales for xenon's use in the mountains, assesses the risks of xenon administration, and considers other aspects of the expedition protocol that likely affected the odds of summit success. Based on this analysis, there is no basis for widespread implementation of xenon inhalation at this time. Evidence of benefit is lacking, and there are strong reasons to believe other aspects of the expedition protocol contributed significantly to the expeditions' outcomes. Much further research on these questions is warranted before any more climbers should engage in this potentially risky practice.

Young, Elizabeth V., Matea A. Djokic, Erica C. Heinrich, Traci Marin, Cecilia Anza-Ramirez, Jeremy E. Orr, Dillon Gilbertson, Pamela N. DeYoung, Gustavo Vizcardo-Galindo, Rómulo Figueroa-Mujica, Francisco C. Villafuerte, Atul Malhotra, and Tatum S. Simonson. The effects of nocturnal hypoxemia on cognitive performance in andean highlanders. High Alt Med Biol. 26:347-354, 2025. Background: Many Andean highlanders exposed to chronic hypoxemia are susceptible to excessive erythrocytosis (EE) and chronic mountain sickness (CMS). Nocturnal hypoxemia is more marked than diurnal hypoxemia and includes sustained and intermittent components. The potential for cognitive impairments related to nocturnal hypoxemia in this population has not been extensively studied, but improved understanding may provide opportunities for the prevention of long-term effects of EE and CMS. Methods: To examine this relationship, 48 participants residing permanently at 4,340 m completed an overnight sleep study and a battery of cognitive function tests that examined a broad range of cognitive domains. Results: Greater nocturnal hypoxemia was associated with longer reaction times on Balloon Analogue Risk Task (BART) (p < 0.01) and Emotion Recognition Test (ERT) (p < 0.01). Longer completion times of Trail Making Task were also associated with increased nocturnal hypoxemia (p = 0.03). Increased hematocrit was similarly associated with longer reaction times on the ERT (p = 0.01) and the BART (p = 0.01). Conclusion: Overall, our results showed that increased nocturnal hypoxemia and higher hematocrit were associated with impairments in cognitive performance in individuals residing permanently at high altitude.

Willixhofer, Robin, Laura Gochicoa-Rangel, Anna Apostolo, Jeness Campodonico, Elisabetta Salvioni, Ada De-Los- Santos-Martínez, Alejandro Reyes-García, Luis Torre-Bouscoulet, Sergio Harari, Federico Tagariello, and Piergiuseppe Agostoni. Improved pulmonary gas exchange at altitudes is due to pulmonary vascular adaptation to chronic hypoxia in urban residents. High Alt Med Biol. 00:00-00, 2025. Background: Chronic exposure to high altitude induces physiological adaptations in the lung, but the specific mechanisms of alveolar-capillary gas exchange adaptation in urban populations remain incompletely understood. Methods: We assessed altitude-related alveolar capillary membrane gas diffusion adaptations in Milan (lowlanders, 120 m) and Mexico City (highlanders, 2,240 m). A 1:1 nearest-neighbor matching by age and sex was performed. Results: Comparison between healthy young adults (n = 246, age <40 years) showed higher diffusing capacity for carbon monoxide (D_LCO: 31.7 [27.4-39.0] vs. 28.2 [24.6-32.8] ml/min/mmHg, p < 0.0001) and pulmonary capillary blood volume (Vcap: 105 [87-113] vs. 84 [71-98] ml, p < 0.0001), but lower membrane diffusing capacity (Dm: 50 [45-60] vs. 61 [51.70] ml/min/mmHg, p < 0.0001) in highlanders. The matching procedure yielded 71 pairs (n = 142) with balanced age and sex distributions (standardized mean differences <0.1). These differences remained significant after matching: highlanders showed higher DLCO (31.7 [27.8-39.1] vs. 27.1 [23.7-32.4] ml/min/mmHg, p < 0.0001), higher Vcap (104 [85-124] vs. 78 [65-96] ml, p < 0.0001), and lower Dm (51 [46-60 vs. 57 [50-68] ml/min/mmHg, p = 0.045). Conclusions: These findings suggest vascular, rather than membrane, adaptation to chronic hypoxia in high-altitude urban residents.

Millet, Grégoire P, Philippe Connes.Sickle Cell Trait is a Risk Factor for Another Form of Altitude Illness. High Alt Med Biol. 00:00-00, 2025.-Acute mountain sickness, high-altitude pulmonary edema, and high-altitude cerebral edema have been widely investigated. In this letter, we claim that beyond these three altitude illnesses, one cannot rule out an additional serious concern related to altitude exposure in a particular population; the individuals with sickle cell trait.

Álvarez-Herms, Jesús, Kilian Jornet, Martin Burtscher, Adriana González, and Adrián Odriozola. Gut microbiota dynamics during extreme altitude climbing: A longitudinal case report. High Alt Med Biol. 00:00-00, 2025.-The present case study would explore the acute changes of gut microbiota (GM) and some physiological responses of a world-class mountaineer during a 4-week stay at altitudes between 3,600 and 4,200 m, with four rapid ascents to different extreme altitudes, that is, 6,700, 7,000, 8,000, and 8,400 m. Severe hypoxemia, hyperglycemia, ketoacidosis, and sympathetic dominance were found to be proportionally higher with increasing altitude. Thus, the GM changed during the acclimatization period, decreasing bacterial diversity (Shannon index from 5.88 to 4.56). Remarkably, during the third week, a transient increase of the pathogenic bacteria Ruminococcus gnavus (+2,800%) was found. Thus, this significant elevation coincided with the impaired systemic health and gastrointestinal and respiratory complications. In conclusion, the present exploratory study found that a favorable and healthy GM profile, characterized by elevated mucolytic and short-chain fatty acids-producing bacteria, may improve hypoxic tolerance, reduce the risk of developing gut leakage syndrome and systemic endotoxemia, and protect against acute mountain sickness.