High altitude medicine & biology最新文献

{"title":"<i>Letter:</i> Passive Normobaric Hypoxic Exposure and High-Altitude Acclimatization in Monozygotic Twins on Mount Everest.","authors":"Patrycja Jonetzko, Kenton Cool, Graham Parrott, Chris Parrott","doi":"10.1177/15578682261441525","DOIUrl":"10.1177/15578682261441525","url":null,"abstract":"","PeriodicalId":12975,"journal":{"name":"High altitude medicine & biology","volume":" ","pages":"282-283"},"PeriodicalIF":1.3,"publicationDate":"2026-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147722169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Compliance and Genetic Variability Are Determinants of the Success of l-Arginine/l-Citrulline Supplementation in High Altitude-A Pilot Study.","authors":"Eduardo Pena, Samia El Alam, Juliane Hannemann, Rainer Böger","doi":"10.1177/15578682261450122","DOIUrl":"10.1177/15578682261450122","url":null,"abstract":"<p><p>Pena, Eduardo, Samia El Alam, Juliane Hannemann, and Rainer Böger. Compliance and genetic variability are determinants of the success of l-arginine/l-citrulline supplementation in high altitude-a pilot study. <i>High Alt Med Biol.</i> 27:245-253, 2026.</p><p><strong>Background: </strong>Asymmetric dimethylarginine (ADMA) is a risk biomarker of high-altitude pulmonary hypertension (HAPH). ADMA is inactivated by dimethylarginine dimethylaminohydrolase (DDAH)1 and 2. Single nucleotide polymorphisms in these genes contribute to genetic predisposition for HAPH. Supplementation with l-arginine may reverse ADMA's inhibitory effect and, thus, HAPH. We conducted a pilot study to test whether supplementation with l-arginine/l-citrulline (A/C) during chronic intermittent hypoxia (CIH) limits the increase in pulmonary arterial pressure (PAP) as compared to placebo.</p><p><strong>Methods: </strong>Twenty male volunteers were randomly assigned to receive 6 months of A/C or placebo; PAP was assessed by echocardiography.</p><p><strong>Results: </strong>l-Arginine increased in the A/C group at month 1, which subsided until month 6 due to poor compliance with the study supplement. Individuals with 2 or more alleles of a previously described DDAH1/2 haplotype showed a higher increase in ADMA during CIH. A/C caused a trend toward a diminished increase in PAP. However, these findings should be interpreted as exploratory, consistent with the low adherence to treatment in this pilot study. The increase in l-arginine blood levels was attenuated in carriers of a previously described ARG1/2 haplotype.</p><p><strong>Conclusion: </strong>Our data show that A/C supplementation may offer an opportunity to alleviate the altitude-induced increase in PAP; however, long-term compliance and genetic factors may affect outcome.</p>","PeriodicalId":12975,"journal":{"name":"High altitude medicine & biology","volume":" ","pages":"245-253"},"PeriodicalIF":1.3,"publicationDate":"2026-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147873954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Slow Symptom Resolution of Acute Altitude Illness Upon Rapid Descent.","authors":"Adam D Hill","doi":"10.1177/15578682261441527","DOIUrl":"10.1177/15578682261441527","url":null,"abstract":"<p><p>Hill, Adam D. Slow symptom resolution of acute altitude illness upon rapid descent. <i>High Alt Med Biol.</i> 27:277-279, 2026.-Acute mountain sickness (AMS) effects roughly one-quarter to more than three-quarters of persons travelling to elevations greater than 2,500 m. Treatment relies primarily on descent or a stoppage of further ascent (with or without pharmacologic therapy) to allow for acclimatization. In the latter approach, acclimatization as heralded by improvement of symptoms can take anywhere from 12 hours to 4 days. The timeline for symptom resolution when descent takes place, however, is not clearly defined. A case is presented of a hiker who suffered from persistent symptoms of AMS for nearly 24 hours despite descending rapidly to sea level.</p>","PeriodicalId":12975,"journal":{"name":"High altitude medicine & biology","volume":" ","pages":"277-279"},"PeriodicalIF":1.3,"publicationDate":"2026-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147632233","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heart Rate Variability in Adults from Low- and High-Altitude Origins Residing in a High-Altitude City: A Cross-Sectional Comparison.","authors":"Esteban Ramírez, C Alejandro Luzardo, Daniel F Namen, Juan D Rivera, Lina Pérez, Daniela Mora, Nicolás Moncada, Santiago Lopez, Jaime Guiza","doi":"10.1177/15578682261438763","DOIUrl":"10.1177/15578682261438763","url":null,"abstract":"<p><p>Ramírez, Esteban, C. Alejandro Luzardo, Daniel F. Namen, Juan D. Rivera, Lina Pérez, Daniela Mora, Nicolás Moncada, Santiago Lopez, and Jaime Guiza. Heart rate variability in adults from low- and high-altitude origins residing in a high-altitude city: a cross-sectional comparison. <i>High Alt Med Biol.</i> 27:222-227, 2026.</p><p><strong>Background: </strong>Heart rate variability (HRV) is used to assess autonomic regulation, reflecting autonomic nervous system activity through heartbeat interval analysis. HRV can be evaluated using time-domain, frequency-domain, and nonlinear methods. Although acute high-altitude exposure has been studied, the effects of chronic exposure remain less well understood.</p><p><strong>Methods: </strong>This study compared HRV in adults from altitudes ≥2,500 m (group 1) and <1,500 m (group 2), with both groups residing in Bogotá, Colombia (2,600 m) for more than 6 months. HRV was assessed using time domain, frequency domain, and nonlinear metrics.</p><p><strong>Results: </strong>Participants from low-altitude regions (group 2) exhibited higher resting heart rates (<i>p</i> = 0.002) and lower time domains (standard deviation of normal-to-normal intervals, root mean square of successive differences, number of pairs of successive normal-to-normal intervals differing by more than 50 ms, percentage of NN50 [%]; <i>p</i> < 0.05), frequency domain (total power, high-frequency power; <i>p</i> ≤ 0.004), and nonlinear measures (triangular interpolation of the NN interval histogram, standard deviation of instantaneous beat-to-beat variability, short-term fractal scaling exponent; <i>p</i> < 0.05) than those from high-altitude regions. These results indicate a lower HRV in individuals from low-altitude regions.</p><p><strong>Conclusion: </strong>Adults raised at low altitudes showed lower HRV when living in Bogotá compared with those raised at high altitudes, suggesting an association with long-term autonomic differences potentially related to early-life altitude exposure, rather than a direct causal effect of chronic hypoxia during childhood. These findings may have physiological and clinical implications, particularly in countries with diverse geography. Further prospective, longitudinal research is needed to confirm these associations and clarify their cardiovascular relevance and the potential contribution of genetic and environmental factors.</p>","PeriodicalId":12975,"journal":{"name":"High altitude medicine & biology","volume":" ","pages":"222-227"},"PeriodicalIF":1.3,"publicationDate":"2026-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147581388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Physiological Responses to Acute Hypobaric and Normobaric Hypoxia: Differences in Maximal Exercise and Clinical Impact.","authors":"Giovanni Ferrarini, Mattia Canevari, Valeria Azzini, Piergiuseppe Agostoni, Beatrice Pezzuto, Carlo Vignati","doi":"10.1177/15578682261442067","DOIUrl":"10.1177/15578682261442067","url":null,"abstract":"<p><p>Ferrarini, Giovanni, Mattia Canevari, Valeria Azzini, Piergiuseppe Agostoni, Beatrice Pezzuto, and Carlo Vignati. Physiological responses to acute hypobaric and normobaric hypoxia: differences in maximal exercise and clinical impact. <i>High Alt Med Biol.</i> 27:259-272, 2026.-Hypoxia, defined by inspired partial pressure of oxygen (PiO₂) <150 mmHg, has been extensively studied in conditions of both reduced barometric pressure (hypobaric hypoxia, HH) and reduced inspired fraction of oxygen (FiO₂) at sea level (normobaric hypoxia, NH). Traditionally considered interchangeable, mounting evidence indicates that HH and NH elicit distinct cardiovascular, ventilatory, and gas-exchange responses during physical effort, likely due to factors beyond PiO₂, including air density, alveolar gas composition, exercise modality, and the age and sex of the individual performing the effort. A thorough understanding of how different hypoxic modalities affect exercise responses provides fundamental insights into human physiology and pathophysiology under extreme conditions, with practical implications for sports medicine and athletic training, as well as for patients with pathologies potentially influenced by hypoxia dealing with high altitude. This narrative review synthesizes current evidence on the differential effects of HH and NH on exercise responses, with an emphasis on maximal exercise capacity and underlying the physiological mechanisms regarding cardiovascular function, ventilatory adaptation, and gas-exchange responses, also outlining the implications for athletes, clinical populations (heart failure, chronic obstructive pulmonary disease, pulmonary hypertension), and altitude medicine.</p>","PeriodicalId":12975,"journal":{"name":"High altitude medicine & biology","volume":" ","pages":"259-272"},"PeriodicalIF":1.3,"publicationDate":"2026-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147689799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Altered Mental Status at High Altitude: Obstructive Hydrocephalus Mimicking High-Altitude Cerebral Edema (HACE).","authors":"Taylor Barg, Jaclyn Walker, Samara Levine, David Ryan Ormond, James P Maloney","doi":"10.1177/15578682251411939","DOIUrl":"10.1177/15578682251411939","url":null,"abstract":"<p><p>Barg, Taylor, Jaclyn Walker, Samara Levine, David Ryan Ormond, and James P Maloney. Altered mental status at high altitude: obstructive hydrocephalus mimicking high altitude cerebral edema (HACE). <i>High Alt Med Biol.</i> 27:273-276, 2026.-A 29-year-old female presented to a Colorado emergency department with amnesia, headache, confusion, and dysarthria after rapidly ascending a 4,404 m (14,267 ft) peak. Head CT revealed cerebral edema and hydrocephalus. She was hypotensive and required vasopressors prior to evacuation to a lower-altitude intensive care unit and received initial treatment for high-altitude cerebral edema (HACE) with dexamethasone. Imaging and clinical workup revealed obstructive hydrocephalus due to a colloid cyst with minimal radiographical evidence of cerebral edema except due to the compressive effects of hydrocephalus. She transiently developed stress-induced cardiomyopathy and mixed neurocardiogenic shock. This case emphasizes the importance of considering HACE mimics at high altitude triggered by hypoxia-mediated increases in intracranial pressure.</p>","PeriodicalId":12975,"journal":{"name":"High altitude medicine & biology","volume":" ","pages":"273-276"},"PeriodicalIF":1.3,"publicationDate":"2026-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145862815","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Mediating Role of Cognitive Function in the Relationship Between Acute High-Altitude Stress and Casualty Care Capability Following Rapid Ascent.","authors":"Tianjing Du, Haoqing Shi, Linlin Liu, Zeyu Yang","doi":"10.1177/15578682261416451","DOIUrl":"10.1177/15578682261416451","url":null,"abstract":"<p><p>Du, Tianjing, Haoqing Shi, Linlin Liu, and Zeyu Yang. The mediating role of cognitive function in the relationship between acute high-altitude stress and casualty care capability following rapid ascent. <i>High Alt Med Biol.</i> 27:209-221, 2026.</p><p><strong>Background: </strong>The impact of high-altitude rescue missions on medical personnel's cognitive function and casualty care capabilities remains unclear.</p><p><strong>Methods: </strong>This multicenter, randomized, sham-controlled clinical trial established high-altitude intervention (HAI), high-altitude (HA), and sea level (SL) groups (<i>n</i> = 92 per group). The HAI group received an integrated cognitive-stress management training, and the HA group implemented a sham training regimen before rapid ascent to high altitude (RAHA). The SL group served as a blank control group. Primary outcomes included casualty care capability score, plasma cortisol level, and cognitive ability score. Longitudinal mediation analysis examined the role of cognitive function in stress and casualty care capabilities.</p><p><strong>Results: </strong>In the HA group, cognitive ability mediated strong negative indirect effects at 24 hours, alongside a positive direct effect of stress. At 48 hours, the negative indirect effect remained dominant, whereas the direct effect of stress was not significant. At 72 hours, the indirect effect weakened but remained significant, whereas the direct effect of stress became significantly negative. By 96 hours, the indirect effect disappeared, with the total effect explained by stress. In the HAI group, the total and indirect effects were significant at 24 and 48 hours, whereas the direct effects were not. At 72 and 96 hours, no effects were statistically significant.</p><p><strong>Conclusion: </strong>During the initial phase of RAHA, cognitive ability serves as a mediating factor through which stress impairs casualty care capabilities. Over time, the mediating effect of cognition gradually diminishes, while the direct negative impact of the stress response continues to strengthen. The integrated cognitive-stress training can effectively preserve cognitive function and mitigate the stress response, thereby enhancing medical personnel's casualty care capabilities.</p>","PeriodicalId":12975,"journal":{"name":"High altitude medicine & biology","volume":" ","pages":"209-221"},"PeriodicalIF":1.3,"publicationDate":"2026-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146029473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Time-Dependent Effects of Chronic Hypoxic Exposure on Microarchitecture of Different Skeletal Sites in Mice.","authors":"Yanli Chen, Suying Zhu, Doudou Hao, Zhiyou Shi, Yang Zhong, Suyuan Wang, Yunhong Wu","doi":"10.1177/15578682261445399","DOIUrl":"10.1177/15578682261445399","url":null,"abstract":"<p><p>Chen, Yanli, Suying Zhu, Doudou Hao, Zhiyou Shi, Yang Zhong, Suyuan Wang, and Yunhong Wu. Time-dependent effects of chronic hypoxic exposure on microarchitecture of different skeletal sites in mice. <i>High Alt Med Biol.</i> 27:228-238, 2026.-High-altitude hypoxia accelerates bone loss by disrupting bone metabolic homeostasis. Currently, hypoxic effects on bone and their link to exposure time remain undefined. This study aimed to systematically evaluate the dynamic effects of chronic hypoxic exposure on bone homeostasis and bone microstructure in different skeletal sites through <i>in vivo</i> and <i>in vitro</i> experiments. Male C57BL/6J mice were exposed to 5,500 m simulated hypoxia for 16 weeks. Micro-CT analyzed cervical (C3-C4), lumbar (L4-L6) vertebrae, and femurs. Histopathological analysis assessed bone tissue and multiorgan pathology. <i>In vitro</i> experiments, a 5% hypoxic culture system was established to detect the proliferation and differentiation capabilities of MC3T3-E1 osteoblasts. After 12 weeks of hypoxic exposure, compared with the control group, the trabecular separation (Tb.Sp) of the mouse femur was significantly increased, and the bone mineral content was significantly decreased. After 16 weeks of exposure, the trabecular bone volume/tissue volume (Tb.BV/TV) and bone mineral density of the cervical vertebrae, lumbar vertebrae, and femurs were significantly reduced. H&E staining showed osteoblasts in multiple bones of hypoxic mice shifted to quiescent states, and long-term hypoxia induced multi-organ damage (pulmonary, renal, colonic, skeletal muscle). 5% hypoxia significantly downregulated collagen type I and alkaline phosphatase (ALP) mRNA levels in MC3T3-E1 cells, inhibited ALP activity and mineralized nodule formation, and reduced osteoblast differentiation capacity. Chronic hypoxic exposure induces bone loss in multiple skeletal sites of mice in a time-dependent manner, with femur showing significantly higher sensitivity to hypoxic exposure than the cervical and lumbar vertebrae. The underlying mechanism may be related to hypoxia inhibiting osteoblast function and disrupting the balance of bone metabolism. Long-term hypoxia also causes pathological damage to multiple organs. This study provides evidence for clarification of the pathological mechanism of hypoxic bone injury and lays a foundation for the subsequent development of targeted intervention strategies for hypoxia-related bone diseases.</p>","PeriodicalId":12975,"journal":{"name":"High altitude medicine & biology","volume":" ","pages":"228-238"},"PeriodicalIF":1.3,"publicationDate":"2026-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147769978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Medical Screening of Climbers Who Later Develop High-Altitude Pulmonary Edema on Aconcagua.","authors":"Aaron Brillhart, Molly Enenbach, Javier Seufferheld, Bernabé Abramor, Peter Callas, Rodrigo Duplessis, Ian Guertin, Theodore A Hartridge, Roxana Pronce, Ana Saravia, Scott E McIntosh","doi":"10.1177/15578682261444634","DOIUrl":"10.1177/15578682261444634","url":null,"abstract":"<p><p>Brillhart, Aaron, Molly Enenbach, Javier Seufferheld, Bernabé Abramor, Peter Callas, Rodrigo Duplessis, Ian Guertin, Theodore A. Hartridge, Roxana Pronce, Ana Saravia, and Scott E. McIntosh. Medical screening of climbers who later develop high-altitude pulmonary edema on Aconcagua. <i>High Alt Med Biol.</i> 27:254-258, 2026.</p><p><strong>Introduction: </strong>On Aconcagua (6,961 m), high-altitude pulmonary edema (HAPE) is the most frequent reason for medical evacuation. This study aimed to compare medical screening data of climbers who developed HAPE with those who did not and to identify trends to aid in illness prevention and climber safety.</p><p><strong>Methods: </strong>De-identified medical screening data of Aconcagua climbers from 2024 to 25 were retrospectively reviewed, comparing climbers who developed HAPE with those who did not.</p><p><strong>Results: </strong>Fifty-three of 2,336 climbers developed HAPE (2.3%). Asymptomatic climbers screened at 4,300 m who later developed HAPE had lower mean oxygen saturation than controls (80% vs. 85%, <i>p</i> < 0.001) and higher mean heart rate (96 vs. 87 bpm, <i>p</i> < 0.001). Nonsignificant trends were noted with guided status (74% vs. 61%, <i>p</i> = 0.06), and prophylactic acetazolamide use (34% vs. 21%, unadjusted: <i>p</i> = 0.02, odds ratio [OR] 1.92, adjusted: <i>p</i> = 0.08, OR 1.74).</p><p><strong>Conclusions: </strong>On Aconcagua, certain vital sign parameters, including oxygen saturation below 80% and tachycardia during asymptomatic screening at 4,300 m, could raise concern for later developing HAPE. Future research could clarify any association between HAPE, certain climber groups such as guided clients, ascent rate, and medication use. Gradual ascent should continue to be emphasized to facilitate acclimatization and prevent life-threatening altitude illness such as HAPE.</p>","PeriodicalId":12975,"journal":{"name":"High altitude medicine & biology","volume":" ","pages":"254-258"},"PeriodicalIF":1.3,"publicationDate":"2026-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147722513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"<i>Letter:</i> The Anticoagulation Dilemma in Atrial Fibrillation Complicating Chronic Mountain Sickness.","authors":"Yue Dong, Zhihao Zou, Qinghai Shi","doi":"10.1177/15578682261442843","DOIUrl":"10.1177/15578682261442843","url":null,"abstract":"","PeriodicalId":12975,"journal":{"name":"High altitude medicine & biology","volume":" ","pages":"280-281"},"PeriodicalIF":1.3,"publicationDate":"2026-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147645065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}