High altitude medicine & biology最新文献

Camacho-Cardenosa, Alba, Marta Camacho-Cardenosa, Johannes Burtscher, Pedro R. Olivares, Guillermo Olcina, and Javier Brazo-Sayavera. Intermittent hypoxic training increases and prolongs exercise benefits in adult untrained women. High Alt Med Biol. 25:274-284, 2024. Background: Exercising in hypoxia may confer multiple health benefits, but the evidence for specific benefits is scarce. Methods: We investigated effects of intermittent hypoxic training (IHT) on the quality of life and functional fitness of healthy adult women, in a double-blind, randomized, placebo-controlled study. Subjects performed 36 sessions of IHT (experimental group, n = 41; fraction of inspired oxygen [FIO₂]: 0.17) or the same training in normoxia (control group, n = 41; FIO₂: 0.21). Health-related quality of life, fitness tests, and hemoglobin levels were assessed before (T1), directly after (T2), and 4 weeks after (T3) cessation. Results: At T2, upper body strength (+14.96%), lower body strength (+26.20%), and agility (-4.94%) increased significantly in the experimental group compared to baseline but not in controls. The experimental group improved lower body strength more (by 9.85%) than controls at T2 and performed significantly better in walking (by 2.92%) and upper body strength testing (by 16.03%), and agility (by 4.54%) at T3. Perceived general health and vitality was significantly greater in the experimental group at T2 and T3 compared with T1. None of these improvements were observed in the control group. Conclusions: IHT is a promising strategy to induce long-lasting fitness benefits in healthy adult women.

Zhao, Linggong, Yujie Huang, and Xiaoling Tan. Preexisting hyperuricemia before high-altitude ascent is associated with a slower recovery of estimated glomerular filtration rate following descent. High Alt Med Biol. 25:308-318, 2024. Objectives: Hypoxia at high altitudes results in elevated uric acid (UA) and reduced estimated glomerular filtration rate (eGFR). However, the impact of a prolonged high-altitude sojourn on UA levels and renal function in patients with preexisting hyperuricemia warrants further exploration. The study was to investigate the eGFR and related factors in patients with preexisting hyperuricemia following exposure to high altitude. Methods: The study included 345 participants, who worked at a high altitude for 1 year. Anthropometric and laboratory indices were collected before ascent (i.e., baseline), as well as 20 and 80 days after descent. The participants were categorized into individuals with hyperuricemia (HUA) or normal uric acid (NUA) group based on the presence or absence of hyperuricemia at baseline. Results: No difference in baseline eGFR was observed between the two groups before ascend or on day 20 after descent (p > 0.05). However, on day 80, eGFR of the HUA group was lower compared with the NUA group (p < 0.05). Correlations existed between post-descent eGFR levels and variables, including sampling time, UA levels, total and direct bilirubin, and baseline grouping. Conclusions: After high-altitude exposure, the recovery of eGFR was delayed in participants with preexisting hyperuricemia. Preexisting hyperuricemia and high-altitude hypoxia jointly contribute to renal impairment.

Strickland, Brian, Elan Small, Mary Ryan, and Ryan Paterson. Effectiveness of continuous positive airway pressure in alleviating hypoxemia and improving exertional capacity at altitude. High Alt Med Biol. 25:319-325, 2024. Introduction: Decreased oxygen saturation and exercise tolerance are commonly experienced at high altitude. Continuous positive airway pressure (CPAP) devices have become increasingly portable and battery powered, providing a potentially unique new therapeutic modality for treatment of altitude-related illnesses. This study evaluated the potential use of CPAP devices to improve and maintain oxygen saturation at altitude, both at rest and with exertion, to evaluate the feasibility of using this device at altitude. Methods: Subjects were taken to Mount Blue Sky and monitored while they hiked to the summit (4,350 m), maintaining a consistent level of exertion. Subjects hiked for 0.7 km both with and without CPAP set to 10 cmH₂O pressure. Continuous vital signs were collected during the hike and recovery period. Results: All subjects completed the hike wearing CPAP devices at a vigorous level of exertion. Mean oxygen saturation of the CPAP group (M = 83.8%, SD = 3.72) was significantly higher than that of the control group during exertion (M = 78.7%, SD = 2.97); p = 0.005. Recovery after exertion was quicker in the CPAP group than the control group. Three subjects experienced claustrophobia requiring a brief pause, but were able to complete their exercise trial without removing equipment or experiencing adverse events. When pauses from claustrophobia were excluded, there was no difference in completion time between the groups (p = 0.06). Conclusion: CPAP reliably improved oxygen saturation at rest and during vigorous exertion at high altitude. Its ability to correct hypoxemia, even with physical exertion, may prove useful after further study as a portable self-carried device to prevent and treat altitude-related illness, or to improve safety in high-altitude rescues.

Objective: We aimed to determine changes in cognitive function resulting from chronic hypobaric hypoxia through proteomic analysis of hippocampal tissue. We screened cognition-related proteins to provide ideas and directions that could help prevent and treat hypoxia-associated cognitive impairment. Methods: We analyzed hippocampal tissues from mice exposed to high altitudes and control mice using 4 D label-free quantitative proteomics. The data were analyzed by protein quantitative analysis, functional annotation, differential protein screening, clustering analyses, and functional classification and enrichment. Differential protein expression was investigated using targeted quantitative omics based on parallel response monitoring. Results: We identified and quantified 20 target proteins in 12 samples, of which 18 were significant validated proteins that were or might be related to cognitive functions. Signaling pathways that were significantly enriched in differentially expressed proteins were pyrimidine metabolism, 5'-Adenosine Triphosphate-activated protein kinase signaling, phospholipase D signaling, purine metabolism, inflammatory mediator regulation of transient receptor potential channels, hedgehog signaling pathways, dilated cardiomyopathy, platelet activation, insulin resistance, mRNA surveillance pathways, drug metabolism-other enzymes, and drug metabolism-cytochrome P450. Conclusion: Chronic hypoxia alters protein expression in murine hippocampal tissues. Eighteen differentially expressed cognition-related proteins might be related to cognitive impairment in mice exposed to chronic high-altitude hypoxia.

Lankford, Harvey V, Hannah Kimberley. Supplemental Oxygen on the Annie Smith Peck Expedition of 1903 to 6,367 m (20,892 ft) Mount Sorata (Illampu). High Alt Med Biol. 00:00-00, 2024. The 1903 expedition to 6,367 m (20,892 ft) Mount Sorata (Illampu) in Bolivia that was conceived, organized, and led by American mountaineer Annie Smith Peck appears to have been the first to take a supplemental oxygen apparatus to a great mountain. The expedition did not have heavy cylinders of compressed oxygen or closed-circuit rebreathers with chemically generated oxygen but took an apparatus to produce oxygen on the mountain apparently by a 19th century heated chlorate chemical method. Oxygen was to be manufactured in camp, stored in rubber bags, and used with an open-circuit breathing set while climbing. The equipment was taken, but once in Bolivia, a late change in plans resulted in a summit attempt on 6,427 m (21,086 ft) Ancohuma rather than Illampu on the twin-peaked Sorata massif. The summit attempt ended prematurely at 4,700 m (15,350 ft), and the oxygen system was not used. The present paper reviews some of the supplemental oxygen options that were available in 1903 and examines the Sorata expedition, a little-known part of the early history of mountaineering oxygen use.

Su, Ping, Masako Taniike, Yuko Ohno, and Ikuko Mohri. The effects of high altitude on children's sleep: A community-based study on preschoolers in the Tibetan Plateau. High Alt Med Biol. 00:00-00, 2024. Objective/Background: It has been reported that high altitude affects breathing during sleep in children. To evaluate the symptoms suspected sleep-disordered breathing (SDB) and sleep quality of preschool children living in high altitude of 2,261-3,800 m above sea level (masl) in the Tibetan Plateau, we conducted the community-based survey using a questionnaire. Patients/Methods: Sleep problems were assessed in 3,113 children aged 3-6 years in Qinghai province using the Chinese version of the Japanese Sleep Questionnaire for Preschoolers (JSQ-P-C), focusing on obstructive sleep apnea (OSA) and OSA-related symptoms. The effect of altitude on these scores was analyzed. Results: The subscale scores of OSA, morning symptoms, and daytime excessive sleepiness in the JSQ-P-C were higher in children living in areas above 3,000 masl than in those living below 3,000 masl and in Japanese children. Altitude, but not family income or maternal education level, significantly affected the scores of OSA, morning symptoms, and daytime excessive sleepiness. Conclusions: Living at altitudes higher than 3,000 masl may adversely affect children's sleep quality.

Horiuchi Masahiro and Samuel J. Oliver. Post-exercise hypotension after exercising in hypoxia with and without tart cherry supplementation. High Alt Med Biol. 00:00-00, 2024. Background: This study investigated the effects of hypoxic exercise with and without tart cherry (TC) supplementation on post-exercise hypotension (PEH). Method: In a randomized order, 12 healthy young adults (9 men and 3 women) completed cycle exercise to exhaustion (1) in normoxia without any supplementation (Norm), (2) in hypoxia (13% O₂) with placebo (Hypo), and (3) in hypoxia with TC supplementation (Hypo + TC). Supplements were supplied for 5 days pre-trial (TC was 200 mg anthocyanin per day for 4 days and 100 mg on day 5). Results: Cycle exercise total energy expenditure was greater in Norm than Hypo and Hypo + TC (p < 0.001) with no difference between Hypo and Hypo + TC (p = 0.41). Mean arterial pressure (MAP) decreased during recovery in all trials (main effect of time, p < 0.001), with no difference in PEH between the trials (p > 0.05, change [Δ] in MAP from pre-exercise at 60 minutes recovery, mean difference, Norm Δ-4.4 mmHg, Hypo Δ-6.1 mmHg, and Hypo + TC Δ-5.2 mmHg). Cardiac baroreflex sensitivity decreased during recovery in all trials (p < 0.001) and was lower in Hypo than Norm and Hypo + TC (main effect of trial, p = 0.02). Conclusion: PEH was not increased after exercise in hypoxia, with or without TC supplementation, compared with exercise in normoxia.