High Altitude Medicine & Biology

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.

Serin, Istemi, Ahmet Unal, Arzu Dobral, Fatma Elif Eroglu, Erdem Ayik, Jale Oz Unal, Mehmet Barış Cengiz, Okan Kati, Toros Taskin, Vural Bastug, and Abdulkadir Karismaz. The Effect of altitude on polycythemia vera: Is it necessary to change limits? High Alt Med Biol. 26:355–360, 2025.

Berendsen, Remco R., Dirk C.A.A. de Vries, Alea Steger, Nadine Herold, Feico J.J. Halbertsma, Adriaan F. Norbart, Hannes Gatterer, and Bengt Kayser. Lack of altitude medicine knowledge among mountaineers in the Italian Alps. High Alt Med Biol. 26:361–373, 2025.

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.

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.

Hilty, Matthias P., Urs Hefti, Pierre Bouzat, Hannes Gatterer, Lenka Horakova, Linda E. Keyes, Justin Lawley, Benjamin D. Levine, George Rodway, Daniel Trevena, Eduardo Vinhaes, and Benoit Champigneulle. Xenon inhalation for expeditions to high altitude: A position statement from the International Climbing and Mountaineering Federation (Union Internationale des Associations d’Alpinisme, UIAA) Medical Commission. High Alt Med Biol. 26:385–387, 2025.

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.

Murphey, Joshua T., Jennifer L. Temple, and David Hostler. Taste and appetite at altitude: A comprehensive review of sensory and hunger modulation in high-altitude environments. High Alt Med Biol. 26:393–407, 2025.

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.

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.

Beresford, Maxwell Oliver, Rhona Loxton, and George W. Rodway. Everest 1924: Observations and impressions from the Journal of Expedition Physician and Naturalist R.W.G. Hingston. High Alt Med Biol. 26:416–423, 2025.—The 1924 British expedition to Mount Everest was the second serious attempt to summit the mountain, following on from the expedition of 1922. Initially led by General Charles Bruce, the party was composed of some of the most prestigious climbers of its day. Major Richard W.G. Hingston, although not a mountaineer by trade, acted as medical officer on the expedition. Hingston maintained a meticulous journal on the expedition, describing medical cases, the events on Everest, and the extensive flora and fauna he collected. He also performed basic physiological testing on the climbers, exploring the impact of altitude on their bodies. While the heights the climbers reached broke records, the expedition was ultimately shrouded in tragedy with the loss of Mallory and Irvine. This article follows Major Hingston’s personal account of events on Everest, including his impressions of Mallory and Irvine. This article considers his observations and findings in their current medical context and emphasizes his passion for the natural world.