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Tao G, Ma H, Su Y. Effects of long-term exposure to high-altitude on episodic memory: The moderating role of daytime dysfunction. Physiol Behav 2024:114700. [PMID: 39332594 DOI: 10.1016/j.physbeh.2024.114700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2024] [Revised: 09/14/2024] [Accepted: 09/20/2024] [Indexed: 09/29/2024]
Abstract
Chronic exposure to high-altitude hypoxic environments may influence short-term memory and working memory. However, its impact on long-term memory, specifically episodic memory, remains understudied. In this study, we systematically investigated the effects of long-term exposure to high altitude (3650 m) on episodic memory, including item memory and source memory. Moreover, we examined the moderating role of daytime dysfunction on the relationship between altitude and episodic memory. In total, 97 participants were enrolled in the study: 49 were from the high altitude (HA) group, comprising those born and raised in low altitude (LA) areas (< 500 m) and had migrated to HA for 2∼3 years after turning 18; and 48 were from the LA group, who had never lived at high altitude. Episodic memory was evaluated using a what-when-where task, whereas daytime dysfunction was measured by the Pittsburgh Sleep Quality Index. For item memory, hit rate and correct rejection rate were significantly lower in the HA group relative to the LA group. For source binding memory, the performance in what-where binding and what-when-where binding were decreased in the HA group, but the what-when binding did not differ between the two groups. Furthermore, the effects of altitude on hit rate, what-where binding, and what-when-where binding were significantly pronounced in individuals with higher levels of daytime dysfunction. These findings suggest that long-term exposure to high-altitude hypoxic environments influences episodic memory performance, including item recognition and source-binding memory. Specifically, spatial source memory is affected by high-altitude exposure, whereas temporal source memory remains unaffected. Moreover, these results highlight the importance of considering sleep quality, especially good daytime function, in maintaining optimal episodic memory function following chronic exposure to high altitudes.
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Affiliation(s)
- Getong Tao
- School of Psychological and Cognitive Sciences, Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing 100871, China.
| | - Hailin Ma
- Key Laboratory of High Altitudes Brain Science and Environmental Acclimation, Tibet University, Lhasa 85000, China.
| | - Yanjie Su
- School of Psychological and Cognitive Sciences, Beijing Key Laboratory of Behavior and Mental Health, Peking University, Beijing 100871, China.
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2
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Isakovich R, Cates VC, Pentz BA, Bird JD, Vanden Berg ER, de Freitas EM, Nysten CE, Leacy JK, O'Halloran KD, Brutsaert TD, Sherpa MT, Day TA. Using modified Fenn diagrams to assess ventilatory acclimatization during ascent to high altitude: Effect of acetazolamide. Exp Physiol 2024; 109:1080-1098. [PMID: 38747161 PMCID: PMC11215491 DOI: 10.1113/ep091748] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Accepted: 03/12/2024] [Indexed: 07/02/2024]
Abstract
High altitude (HA) ascent imposes systemic hypoxia and associated risk of acute mountain sickness. Acute hypoxia elicits a hypoxic ventilatory response (HVR), which is augmented with chronic HA exposure (i.e., ventilatory acclimatization; VA). However, laboratory-based HVR tests lack portability and feasibility in field studies. As an alternative, we aimed to characterize area under the curve (AUC) calculations on Fenn diagrams, modified by plotting portable measurements of end-tidal carbon dioxide (P ETC O 2 ${P_{{\mathrm{ETC}}{{\mathrm{O}}_{\mathrm{2}}}}}$ ) against peripheral oxygen saturation (S p O 2 ${S_{{\mathrm{p}}{{\mathrm{O}}_{\mathrm{2}}}}}$ ) to characterize and quantify VA during incremental ascent to HA (n = 46). Secondarily, these participants were compared with a separate group following the identical ascent profile whilst self-administering a prophylactic oral dose of acetazolamide (Az; 125 mg BID; n = 20) during ascent. First, morningP ETC O 2 ${P_{{\mathrm{ETC}}{{\mathrm{O}}_{\mathrm{2}}}}}$ andS p O 2 ${S_{{\mathrm{p}}{{\mathrm{O}}_{\mathrm{2}}}}}$ measurements were collected on 46 acetazolamide-free (NAz) lowland participants during an incremental ascent over 10 days to 5160 m in the Nepal Himalaya. AUC was calculated from individually constructed Fenn diagrams, with a trichotomized split on ranked values characterizing the smallest, medium, and largest magnitudes of AUC, representing high (n = 15), moderate (n = 16), and low (n = 15) degrees of acclimatization. After characterizing the range of response magnitudes, we further demonstrated that AUC magnitudes were significantly smaller in the Az group compared to the NAz group (P = 0.0021), suggesting improved VA. These results suggest that calculating AUC on modified Fenn diagrams has utility in assessing VA in large groups of trekkers during incremental ascent to HA, due to the associated portability and congruency with known physiology, although this novel analytical method requires further validation in controlled experiments. HIGHLIGHTS: What is the central question of this study? What are the characteristics of a novel methodological approach to assess ventilatory acclimatization (VA) with incremental ascent to high altitude (HA)? What is the main finding and its importance? Area under the curve (AUC) magnitudes calculated from modified Fenn diagrams were significantly smaller in trekkers taking an oral prophylactic dose of acetazolamide compared to an acetazolamide-free group, suggesting improved VA. During incremental HA ascent, quantifying AUC using modified Fenn diagrams is feasible to assess VA in large groups of trekkers with ascent, although this novel analytical method requires further validation in controlled experiments.
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Affiliation(s)
- Rodion Isakovich
- Department of Biology, Faculty of Science and TechnologyMount Royal UniversityCalgaryAlbertaCanada
| | - Valerie C. Cates
- Department of Biology, Faculty of Science and TechnologyMount Royal UniversityCalgaryAlbertaCanada
| | - Brandon A. Pentz
- Department of Biology, Faculty of Science and TechnologyMount Royal UniversityCalgaryAlbertaCanada
| | - Jordan D. Bird
- Department of Biology, Faculty of Science and TechnologyMount Royal UniversityCalgaryAlbertaCanada
| | - Emily R. Vanden Berg
- Department of Biology, Faculty of Science and TechnologyMount Royal UniversityCalgaryAlbertaCanada
| | - Emily M. de Freitas
- Department of Biology, Faculty of Science and TechnologyMount Royal UniversityCalgaryAlbertaCanada
| | - Cassandra E. Nysten
- Department of Biology, Faculty of Science and TechnologyMount Royal UniversityCalgaryAlbertaCanada
| | - Jack K. Leacy
- Department of Biology, Faculty of Science and TechnologyMount Royal UniversityCalgaryAlbertaCanada
- Department of Physiology, School of Medicine, College of Medicine & HealthUniversity Cork CollegeCorkIreland
| | - Ken D. O'Halloran
- Department of Physiology, School of Medicine, College of Medicine & HealthUniversity Cork CollegeCorkIreland
| | | | | | - Trevor A. Day
- Department of Biology, Faculty of Science and TechnologyMount Royal UniversityCalgaryAlbertaCanada
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3
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Liu B, Yuan M, Yang M, Zhu H, Zhang W. The Effect of High-Altitude Hypoxia on Neuropsychiatric Functions. High Alt Med Biol 2024; 25:26-41. [PMID: 37815821 DOI: 10.1089/ham.2022.0136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/11/2023] Open
Abstract
Liu, Bo, Minlan Yuan, Mei Yang, Hongru Zhu, and Wei Zhang. The effect of high-altitude hypoxia on neuropsychiatric functions. High Alt Med Biol. 25:26-41, 2024. Background: In recent years, there has been a growing popularity in engaging in activities at high altitudes, such as hiking and work. However, these high-altitude environments pose risks of hypoxia, which can lead to various acute or chronic cerebral diseases. These conditions include common neurological diseases such as acute mountain sickness (AMS), high-altitude cerebral edema, and altitude-related cerebrovascular diseases, as well as psychiatric disorders such as anxiety, depression, and psychosis. However, reviews of altitude-related neuropsychiatric conditions and their potential mechanisms are rare. Methods: We conducted searches on PubMed and Google Scholar, exploring existing literature encompassing preclinical and clinical studies. Our aim was to summarize the prevalent neuropsychiatric diseases induced by altitude hypoxia, the potential pathophysiological mechanisms, as well as the available pharmacological and nonpharmacological strategies for prevention and intervention. Results: The development of altitude-related cerebral diseases may arise from various pathogenic processes, including neurovascular alterations associated with hypoxia, cytotoxic responses, activation of reactive oxygen species, and dysregulation of the expression of hypoxia inducible factor-1 and nuclear factor erythroid 2-related factor 2. Furthermore, the interplay between hypoxia-induced neurological and psychiatric changes is believed to play a role in the progression of brain damage. Conclusions: While there is some evidence pointing to pathophysiological changes in hypoxia-induced brain damage, the precise mechanisms responsible for neuropsychiatric alterations remain elusive. Currently, the range of prevention and intervention strategies available is primarily focused on addressing AMS, with a preference for prevention rather than treatment.
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Affiliation(s)
- Bo Liu
- Mental Health Center and Psychiatric Laboratory, West China Hospital of Sichuan University, Chengdu, China
- Zigong Mental Health Center, Zigong, China
| | - Minlan Yuan
- Mental Health Center and Psychiatric Laboratory, West China Hospital of Sichuan University, Chengdu, China
| | - Mei Yang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China School of Basic Medical Sciences and Forensic Medicine, Chengdu, Sichuan
| | - Hongru Zhu
- Mental Health Center and Psychiatric Laboratory, West China Hospital of Sichuan University, Chengdu, China
| | - Wei Zhang
- Mental Health Center and Psychiatric Laboratory, West China Hospital of Sichuan University, Chengdu, China
- West China Biomedical Big Data Center, West China Hospital, Sichuan University, Chengdu, China
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4
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van den Berg NH, Michaud X, Pattyn N, Simonelli G. How Sleep Research in Extreme Environments Can Inform the Military: Advocating for a Transactional Model of Sleep Adaptation. Curr Psychiatry Rep 2023; 25:73-91. [PMID: 36790725 DOI: 10.1007/s11920-022-01407-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/06/2022] [Indexed: 02/16/2023]
Abstract
PURPOSE OF REVIEW We review the literature on sleep in extreme environments. Accordingly, we present a model that identifies the need for mitigating interventions to preserve sleep quality for military deployments. RECENT FINDINGS Situational factors that affect sleep in extreme environments include cold temperatures, isolated and confined areas, fluctuating seasonality, photoperiodicity, and extreme latitudes and altitudes. Results vary across studies, but general effects include decreased total sleep time, poor sleep efficiency, and non-specific phase delays or phase advances in sleep onset and sleep architecture. Considering habitability measures (e.g., light or temperature control) and individual differences such as variable stress responses or sleep need can mitigate these effects to improve mood, cognition, and operational performance. Although the situational demands during military missions inevitably reduce total sleep time and sleep efficiency, mitigating factors can attenuate sleep-related impairments, hence allowing for optimal mission success and personnel safety.
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Affiliation(s)
- N H van den Berg
- Centre d'études avancées en médecine du sommeil, Hôpital du Sacré-Coeur de Montréal, CIUSSS du Nord de l'Île-de-Montréal, Montreal, Quebec, Canada.,School of Psychology, Faculty of Social Sciences, University of Ottawa, Ottawa, Ontario, Canada
| | - X Michaud
- Centre d'études avancées en médecine du sommeil, Hôpital du Sacré-Coeur de Montréal, CIUSSS du Nord de l'Île-de-Montréal, Montreal, Quebec, Canada.,Department of Psychology, Faculty of Arts and Science, Université de Montréal, Montreal, Quebec, Canada
| | - N Pattyn
- Department of Medicine, Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada.,Human Physiology Department (MFYS), Vrije Universiteit Brussel, Brussels, Belgium.,VIPER Research Unit, Royal Military Academy, Brussels, Belgium
| | - G Simonelli
- Centre d'études avancées en médecine du sommeil, Hôpital du Sacré-Coeur de Montréal, CIUSSS du Nord de l'Île-de-Montréal, Montreal, Quebec, Canada. .,Department of Medicine, Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada. .,Department of Neuroscience, Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada.
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Burtscher J, Niedermeier M, Hüfner K, van den Burg E, Kopp M, Stoop R, Burtscher M, Gatterer H, Millet GP. The interplay of hypoxic and mental stress: Implications for anxiety and depressive disorders. Neurosci Biobehav Rev 2022; 138:104718. [PMID: 35661753 DOI: 10.1016/j.neubiorev.2022.104718] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/26/2022] [Accepted: 05/27/2022] [Indexed: 12/14/2022]
Abstract
Adequate oxygen supply is essential for the human brain to meet its high energy demands. Therefore, elaborate molecular and systemic mechanism are in place to enable adaptation to low oxygen availability. Anxiety and depressive disorders are characterized by alterations in brain oxygen metabolism and of its components, such as mitochondria or hypoxia inducible factor (HIF)-pathways. Conversely, sensitivity and tolerance to hypoxia may depend on parameters of mental stress and the severity of anxiety and depressive disorders. Here we discuss relevant mechanisms of adaptations to hypoxia, as well as their involvement in mental stress and the etiopathogenesis of anxiety and depressive disorders. We suggest that mechanisms of adaptations to hypoxia (including metabolic responses, inflammation, and the activation of chemosensitive brain regions) modulate and are modulated by stress-related pathways and associated psychiatric diseases. While severe chronic hypoxia or dysfunctional hypoxia adaptations can contribute to the pathogenesis of anxiety and depressive disorders, harnessing controlled responses to hypoxia to increase cellular and psychological resilience emerges as a novel treatment strategy for these diseases.
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Affiliation(s)
- Johannes Burtscher
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland; Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland.
| | - Martin Niedermeier
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Katharina Hüfner
- Department of Psychiatry, Psychotherapy, Psychosomatics and Medical Psychology, University Clinic for Psychiatry II, Innsbruck Medical University, Innsbruck, Austria
| | - Erwin van den Burg
- Department of Psychiatry, Center of Psychiatric Neuroscience (CNP), University Hospital of Lausanne (CHUV), Prilly, Lausanne, Switzerland
| | - Martin Kopp
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Ron Stoop
- Department of Psychiatry, Center of Psychiatric Neuroscience (CNP), University Hospital of Lausanne (CHUV), Prilly, Lausanne, Switzerland
| | - Martin Burtscher
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Hannes Gatterer
- Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy
| | - Grégoire P Millet
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland; Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
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6
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Heiniger G, Walbaum S, Sartori C, Lovis A, Sazzini M, Wellman A, Heinzer R. Altitude-Induced Sleep Apnea Is Highly Dependent on Ethnic Background (Sherpa Vs. Tamang). High Alt Med Biol 2022; 23:165-172. [PMID: 35708530 DOI: 10.1089/ham.2022.0012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Heiniger, Grégory, Simon Walbaum, Claudio Sartori, Alban Lovis, Marco Sazzini, Andrew Wellman, and Raphael Heinzer. Altitude-Induced Sleep Apnea Is Highly Dependent on Ethnic Background (Sherpa Vs. Tamang). High Alt Med Biol. 23:165-172, 2022. Rationale: High altitude-induced hypocapnic alkalosis generates central sleep apnea (CSA). In Nepal, two ethnic groups live at medium-to-high altitude: Tamangs originate from low-altitude Tibeto-Burman populations, whereas Sherpas descend from high-altitude Tibetans. Objective: To compare apnea severity at low and high altitude between Sherpas and Tamangs. Methods: Polygraphy recordings, including airflow and oxygen saturation, were performed in Nepal at "low" (2,030 m) and "high" (4,380 m) altitudes. Resting ventilation (V̇E) and mixed-exhaled CO2 (FECO2) were also measured at the same altitudes. Differences in apnea-hypopnea index (AHI), oxygen desaturation index (ODI), and % of nocturnal periodic breathing (NPB) at the two altitudes were compared between ethnicities. Measurements and Main Results: Twenty Sherpas and 20 Tamangs were included (males, median [interquartile range] age: 24.5 [21.5-27.8] years vs. 26.0 [21.5-39.8] years, body mass index: 23.9 [22.1-26.1] kg/m2 vs. 25.21 [20.6-27.6] kg/m2). Compared with Tamangs, Sherpas showed a lower increase in AHI (+7.5 [2.6-17.2]/h vs. +31.5 [18.2-57.3]/h, p < 0.001), ODI (+13.8 [5.5-28.2]/h vs. +42.0 [22.6-77.6]/h, p < 0.001), and NPB proportion (+0.9 [0-3.5]% vs. +12.8 [3.1-27.4]%, p < 0.001) from low to high altitude. Resting V̇E was higher in Sherpas versus Tamangs at both low (8.45 [6.89-10.70] l/min vs. 6.3 [4.9-8.3] l/min, p = 0.005) and high (9.7 [8.5-11] l/min vs. 8.74 [7.39-9.73] l/min, p = 0.020) altitudes, whereas the mean ± standard deviation FECO2 decrease between low and high altitude was greater in Tamangs versus Sherpas (-0.50% ± 0.44% vs. -0.80% ± 0.33%, p < 0.023). Conclusion: Overall, altitude-adapted Sherpas showed a 3.2-times smaller increase in sleep-disordered breathing between low and high altitude compared with Tamangs, and higher ventilation and a smaller drop in FECO2 at high altitude. These data suggest that genetic differences in breathing control can be protective against CSA.
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Affiliation(s)
- Grégory Heiniger
- Center for Investigation and Research in Sleep, University Hospital of Lausanne, Lausanne, Switzerland
| | - Simon Walbaum
- Department of Internal Medicine and University Hospital of Lausanne, Lausanne, Switzerland
| | - Claudio Sartori
- Department of Internal Medicine and University Hospital of Lausanne, Lausanne, Switzerland
| | - Alban Lovis
- Department of Pulmonary, University Hospital of Lausanne, Lausanne, Switzerland
| | - Marco Sazzini
- Interdepartmental Centre Alma Mater Research Institute on Global Challenges and Climate Change, University of Bologna, Bologna, Italy.,Department of Biological, Geological and Environmental Sciences (BiGeA), Laboratory of Molecular Anthropology and Centre for Genome Biology, University of Bologna, Bologna, Italy
| | - Andrew Wellman
- Division of Sleep Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Raphael Heinzer
- Center for Investigation and Research in Sleep, University Hospital of Lausanne, Lausanne, Switzerland
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Tan L, Li T, Luo L, Xue X, Lei F, Ren R, Zhang Y, He J, Bloch KE, Tang X. The Characteristics of Sleep Apnea in Tibetans and Han Long-Term High Altitude Residents. Nat Sci Sleep 2022; 14:1533-1544. [PMID: 36072275 PMCID: PMC9444001 DOI: 10.2147/nss.s371388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 08/23/2022] [Indexed: 11/29/2022] Open
Abstract
PURPOSE Obstructive sleep apnea (OSA) is common both at low and high altitude. Since adaptations to high altitude and respiratory control may differ among Tibetans and Hans, we compared characteristics of sleep-disordered breathing in the two ethnic groups at high altitude. MATERIALS AND METHODS This was a prospective observational study including 86 Tibetan and Han long-term (>5 years) high altitude residents with chief complaints of snoring and/or witnessed apnea underwent clinical evaluation and polysomnography at 3200 meters in Shangri-La, China. RESULTS In 42 Tibetans, 38 men, median (quartiles) age was 50.0 (41.0; 56.0)y, total apnea/hypopnea index (AHI) 53.9 (32.0; 77.5)/h, obstructive AHI 51.0 (28.0; 72.2)/h and central AHI 1.5 (0.2; 3.1)/h. In 44 Hans, 32 men, median (quartiles) age was 47.0 (43.5; 51.0)y, total AHI 22.2 (12.8; 39.2)/h, obstructive AHI 17.7 (12.0; 33.0)/h and central AHI 2.4 (0.5; 3.4)/h (p < 0.001 total and obstructive AHI vs Tibetans). In Tibetans, mean nocturnal oxygen saturation was lower [median 85.0 (83.0; 88.0)% vs 88.5 (87.0; 90.0)%] and obstructive apnea and hypopnea duration was longer [22.0 (19.6; 24.8) sec vs 18.3 (16.7; 20.6) sec] than in Hans (all p < 0.001). In regression analysis, Tibetan ethnicity, neck circumference and high-altitude living duration were the predictors of total AHI. We also found that with every 10/h increase in total AHI, there were an approximately 0.9 beat/min and 0.8 beat/min increase in mean heart rate during rapid eye movement (REM) and non-REM sleep and 1.9 mmHg and 2.0 mmHg increase in evening and morning systolic blood pressure. CONCLUSION Our data suggest that Tibetans presented more severe obstructive sleep apnea, hypoxemia and longer apnea duration compared to Hans at 3200 meters, which was correlated with higher heart rate and blood pressure suggesting a greater cardiovascular risk.
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Affiliation(s)
- Lu Tan
- Sleep Medicine Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Taomei Li
- Sleep Medicine Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Lian Luo
- Sleep Medicine Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Xiaofang Xue
- Department of Emergency, Diqing Tibetan Autonomous Prefectural People's Hospital, Shangri-La, People's Republic of China.,Department of Intensive Care Unit, Diqing Tibetan Autonomous Prefectural People's Hospital, Shangri-La, People's Republic of China
| | - Fei Lei
- Sleep Medicine Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Rong Ren
- Sleep Medicine Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Ye Zhang
- Sleep Medicine Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Jiaming He
- Department of Emergency, Diqing Tibetan Autonomous Prefectural People's Hospital, Shangri-La, People's Republic of China.,Department of Intensive Care Unit, Diqing Tibetan Autonomous Prefectural People's Hospital, Shangri-La, People's Republic of China
| | - Konrad E Bloch
- Department of Respiratory Medicine, Sleep Disorders Center, University Hospital of Zurich, Zurich, Switzerland
| | - Xiangdong Tang
- Sleep Medicine Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China.,Mental Health Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China.,Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu, People's Republic of China.,State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, People's Republic of China
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8
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The onset of sleep disturbances and their associations with anxiety after acute high-altitude exposure at 3700 m. Transl Psychiatry 2019; 9:175. [PMID: 31332159 PMCID: PMC6646382 DOI: 10.1038/s41398-019-0510-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 04/30/2019] [Accepted: 05/31/2019] [Indexed: 11/22/2022] Open
Abstract
Sleep disturbances and psychiatric repercussions pose great challenges at high altitude; however, few studies have investigated sleep disturbance and anxiety profiles and their associations after acute exposure in consecutive patients. Thus, we aimed to study the profiles of sleep disturbances in consecutive patients after high-altitude exposure and the association of such disturbances with anxiety. A total of 668 participants were recruited at sea level and 3700 m. The trials were performed at sea level (1 week prior to a 2-h flight to a high-altitude destination) and at 3700 m (24, 72, and 168 h). Sleep disturbances were assessed by self-reported sleep patterns and scores on the Athens Insomnia Scale (AIS). State anxiety was assessed using the Self-Rating Anxiety Scale (SAS). In our study, the incidence of sleep disturbances increased significantly after acute high-altitude exposure (65.3%, 434/668) and then gradually decreased after 72 h (50%, 141/282) and 168 h (44%, 124/282). The sleep assessments AIS [2.0 (4.0) vs. 4.0 (5.0)] and ESS [4.0 (4.0) vs. 5.0 (5.0)] increased significantly (p < 0.05). Also, the SAS increased significantly from 26.25 (3.75) to 28.75 (7.5). The SAS was significantly high in sleep disturbance group [31.25 (7.5) vs. 27.5 (5), p < 0.001] than in the non-sleep- disturbance group. The baseline SAS and AIS scores were significantly higher in participants with sleep disturbances than in those without (p < 0.01). Age, baseline insomnia, sleepiness, fatigue, and higher SAS were predictors of sleep disturbances in univariate regression (all p values < 0.05). However, only an older age (p = 0.045) and a higher baseline SAS (p = 0.018) remained independent predictors of sleep disturbances. Our findings indicated that acute high-altitude exposure triggers the onset of sleep disturbances, which are closely associated with anxiety. Furthermore, baseline state anxiety and age are independent predictors of sleep disturbances at high altitude.
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9
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de Aquino Lemos V, dos Santos RVT, Antunes HKM, Behn C, Viscor G, Lira FS, Bittar IGL, Caris AV, Tufik S, De Mello MT. Melatonin and sleep responses to normobaric hypoxia and aerobic physical exercise: A randomized controlled trial. Physiol Behav 2018; 196:95-103. [DOI: 10.1016/j.physbeh.2018.08.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 08/27/2018] [Accepted: 08/27/2018] [Indexed: 12/11/2022]
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10
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Kong F, Liu G, Xu J. Pharmacological agents for improving sleep quality at high altitude: a systematic review and meta-analysis of randomized controlled trials. Sleep Med 2018; 51:105-114. [PMID: 30121387 DOI: 10.1016/j.sleep.2018.06.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 03/13/2018] [Accepted: 06/02/2018] [Indexed: 01/20/2023]
Abstract
Several hypnotic agents commonly recommended for improving sleep at sea level are discouraged at high altitude. We aimed to evaluate the efficacy and safety of drugs prescribed for improving sleep quality in patients with acute exposure to high altitudes by conducting a systematic review and meta-analysis. An electronic search was executed for randomized controlled trials comparing drug treatments with placebo and no-treatment conditions, which used objective sleep parameters or subjective sleep quality evaluations. Eight studies (152 participants) were included in the meta-analysis and involved trials using acetazolamide, temazepam, zolpidem, zaleplon, and theophylline. Generally, the nonbenzodiazepines were reported to be superior and safe in improving sleep quality. Participants who were administered zaleplon or zolpidem reported a significant improvement in subjective sleep quality. As measured by polysomnography, both zaleplon and zolpidem improved the total sleep time, sleep efficiency index, and stage 4 sleep duration, whereas they decreased the wake-after-sleep onset without impairing ventilation. In contrast, temazepam was not superior to placebo in terms of quicker onset of sleep and better sleep quality. On the other hand, acetazolamide and theophylline both reduced the sleep efficiency index. The present results favored zaleplon and zolpidem in improving both the objective and subjective quality of sleep without impairing ventilation.
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Affiliation(s)
- Fanyi Kong
- Department of Neurology, Kunming General Hospital of Chengdu Military Command, People's Liberation Army, School of Clinical Medicine, Kunming Medical University, No. 212, Yunnan Province, PR China.
| | - Guoyi Liu
- Department of Neurology, First Affiliated Hospital of Kunming Medical University, Yunnan Province, PR China
| | - Jingjing Xu
- Department of Neurology, Kunming General Hospital of Chengdu Military Command, People's Liberation Army, School of Clinical Medicine, Kunming Medical University, No. 212, Yunnan Province, PR China
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11
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Gupta R, Ulfberg J, Allen RP, Goel D. Comparison of Subjective Sleep Quality of Long-Term Residents at Low and High Altitudes: SARAHA Study. J Clin Sleep Med 2018; 14:15-21. [PMID: 29198293 DOI: 10.5664/jcsm.6870] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2017] [Accepted: 09/26/2017] [Indexed: 12/21/2022]
Abstract
STUDY OBJECTIVES To study the effect of altitude on subjective sleep quality in populations living at high and low altitudes after excluding cases of restless legs syndrome (RLS). METHODS This population-based study was conducted at three different altitudes (400 m, 1,900-2,000 m, and 3,200 m above sea level). All consenting subjects available from random stratified sampling in the Himalayan and sub-Himalayan regions of India were included in the study (ages 18 to 84 years). Sleep quality and RLS status were assessed using validated translations of Pittsburgh Sleep Quality Index (PSQI) and Cambridge Hopkins RLS diagnostic questionnaire. Recent medical records were screened to gather data for medical morbidities. RESULTS In the total sample of 1,689 participants included, 55.2% were women and average age of included subjects was 35.2 (± 10.9) years. In this sample, overall 18.4% reported poor quality of sleep (PSQI ≥ 5). Poor quality of sleep was reported more commonly at high altitude compared to low altitude (odds ratio [OR] = 2.65; 95% CI = 1.9-3.7; P < .001). It was more frequently reported among patients with RLS (29.7% versus 17.1% without RLS; P < .001). Other factors that were associated with poor quality of sleep were male sex, smoking, chronic obstructive pulmonary disease (COPD), and varicose veins. Binary logistic regression indicated that COPD (OR = 1.97; 95% CI = 1.36-2.86; P < .001), high altitude (OR = 2.22; 95% CI = 1.55-3.18; P < .001), and RLS (OR = 1.66; 95% CI = 1.12-2.46; P = .01) increased the odds for poor quality of sleep. CONCLUSIONS This study showed that poor quality of sleep was approximately twice as prevalent at high altitudes compared to low altitudes even after removing the potential confounders such as RLS and COPD.
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Affiliation(s)
- Ravi Gupta
- Department of Psychiatry, Himalayan Institute of Medical Sciences, Swami Ram Nagar, Jolly Grant, Dehradun, India.,Sleep Clinic, Himalayan Institute of Medical Sciences, Swami Ram Nagar, Jolly Grant, Dehradun, India
| | - Jan Ulfberg
- Sleep Clinic, Capio Medical Center, Hamnplan, Örebro, Sweden
| | - Richard P Allen
- Department of Neurology, John Hopkins University, Baltimore, Maryland
| | - Deepak Goel
- Sleep Clinic, Himalayan Institute of Medical Sciences, Swami Ram Nagar, Jolly Grant, Dehradun, India.,Department of Neurology, Himalayan Institute of Medical Sciences, Swami Ram Nagar, Jolly Grant, Dehradun, India
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