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Riveros-Rivera A, Penzel T, Gunga HC, Opatz O, Paul F, Klug L, Boschmann M, Mähler A. Hypoxia Differentially Affects Healthy Men and Women During a Daytime Nap With a Dose-Response Relationship: a Randomized, Cross-Over Pilot Study. Front Physiol 2022; 13:899636. [PMID: 35685284 PMCID: PMC9171024 DOI: 10.3389/fphys.2022.899636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 04/18/2022] [Indexed: 11/13/2022] Open
Abstract
Context: The use of daytime napping as a countermeasure in sleep disturbances has been recommended but its physiological evaluation at high altitude is limited. Objective: To evaluate the neuroendocrine response to hypoxic stress during a daytime nap and its cognitive impact. Design, Subject, and Setting: Randomized, single-blind, three period cross-over pilot study conducted with 15 healthy lowlander subjects (8 women) with a mean (SD) age of 29(6) years (Clinicaltrials identifier: NCT04146857, https://clinicaltrials.gov/ct2/show/NCT04146857?cond=napping&draw=3&rank=12). Interventions: Volunteers underwent a polysomnography, hematological and cognitive evaluation around a 90 min midday nap, being allocated to a randomized sequence of three conditions: normobaric normoxia (NN), normobaric hypoxia at FiO2 14.7% (NH15) and 12.5% (NH13), with a washout period of 1 week between conditions. Results: Primary outcome was the interbeat period measured by the RR interval with electrocardiogram. Compared to normobaric normoxia, RR during napping was shortened by 57 and 206 ms under NH15 and NH13 conditions, respectively (p < 0.001). Sympathetic predominance was evident by heart rate variability analysis and increased epinephrine levels. Concomitantly, there were significant changes in endocrine parameters such as erythropoietin (∼6 UI/L) and cortisol (∼100 nmol/L) (NH13 vs. NN, p < 0.001). Cognitive evaluation revealed changes in the color-word Stroop test. Additionally, although sleep efficiency was preserved, polysomnography showed lesser deep sleep and REM sleep, and periodic breathing, predominantly in men. Conclusion: Although napping in simulated altitude does not appear to significantly affect cognitive performance, sex-dependent changes in cardiac autonomic modulation and respiratory pattern should be considered before napping is prescribed as a countermeasure.
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Affiliation(s)
- Alain Riveros-Rivera
- Center for Space Medicine and Extreme Environments Berlin, Institute of Physiology, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
- Department of Physiological Sciences, Faculty of Medicine, Pontificia Universidad Javeriana, Bogotá, Colombia
| | - Thomas Penzel
- Interdisciplinary Center of Sleep Medicine, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Hanns-Christian Gunga
- Center for Space Medicine and Extreme Environments Berlin, Institute of Physiology, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Oliver Opatz
- Center for Space Medicine and Extreme Environments Berlin, Institute of Physiology, Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Friedemann Paul
- Experimental and Clinical Research Center, A Cooperation Between the Max-Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin Berlin, Berlin, Germany
- Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Experimental and Clinical Research Center, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Lars Klug
- Experimental and Clinical Research Center, A Cooperation Between the Max-Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin Berlin, Berlin, Germany
- Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Experimental and Clinical Research Center, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Michael Boschmann
- Experimental and Clinical Research Center, A Cooperation Between the Max-Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin Berlin, Berlin, Germany
- Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Experimental and Clinical Research Center, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
| | - Anja Mähler
- Experimental and Clinical Research Center, A Cooperation Between the Max-Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin Berlin, Berlin, Germany
- Charité–Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Experimental and Clinical Research Center, Berlin, Germany
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Berlin, Berlin, Germany
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Hung PH, Lin FC, Tsai HC, Chao HS, Chou CW, Chang SC. The usefulness of prophylactic use of acetazolamide in subjects with acute mountain sickness. J Chin Med Assoc 2019; 82:126-132. [PMID: 30839503 DOI: 10.1097/jcma.0000000000000014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND The mechanisms of acetazolamide (ACZ) in the prophylaxis of acute mountain sickness (AMS) remain unclear. This study evaluated the changes in physiological variables of sleep and heart rate variability (HRV) in subjects with earlier history of AMS who underwent prophylactic treatment of ACZ. METHODS Nonacclimatized healthy subjects were transported using a bus from 555 m to 3150 m within 3 hours. Polysomnography (PSG) was performed 3 days before ascent (T0), for two consecutive nights at 3150 m (T1 and T2), and 2 days after descent (T3). HRV was measured before sleep and after awakening from T0 to T3. AMS was diagnosed using a self-reported Lake Louise score questionnaire. Subjects found confirmed to have AMS were enrolled in this study. The physiological variables and HRV were compared in AMS subjects without (control group) and with prophylactic ACZ (prophylactic ACZ group). RESULTS Thirteen AMS subjects were enrolled. The PSG results were analyzed in eight and HRV were analyzed in nine of the 13 subjects. The prophylactic use of ACZ in the subjects with a history of AMS significantly improved sleep efficiency (p = 0.012) and awakening percentages (p = 0.017) at T1, significantly higher levels of arterial oxygen saturation (SaO2) and lower values of partial pressure end-tidal carbon dioxide tension (PETCO2) at four time points. Furthermore, they had a higher rapid eye movement sleep percentage (p = 0.05) at T2. Prophylactic ACZ treatment significantly increased the normalized unit of high frequency at T1 after awakening (p = 0.028). CONCLUSION Significantly higher quality of sleep, higher SaO2 during sleep, and lower PETCO2 at high altitude were found in the subjects with a history of AMS using prophylactic ACZ before rapid ascent. ACZ may accelerate the acclimatization process for rapid ascents to high altitudes by increasing parasympathetic tone based on HRV analyses.
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Affiliation(s)
- Pin-Hsi Hung
- Institute of Emergency and Critical Care Medicine, National Yang-Ming University, Taipei, Taiwan, ROC
- Department of Ear-Nose-Throat, Taipei City Hospital, Yangming Branch, Taipei, Taiwan, ROC
| | - Fang-Chi Lin
- Department of Chest Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- Department of Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan, ROC
| | - Han-Chen Tsai
- Department of Nursing, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - Heng-Sheng Chao
- Department of Chest Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- Department of Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan, ROC
| | - Chung-Wei Chou
- Department of Chest Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
- Department of Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan, ROC
| | - Shi-Chuan Chang
- Institute of Emergency and Critical Care Medicine, National Yang-Ming University, Taipei, Taiwan, ROC
- Department of Chest Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
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Hamm W, von Stülpnagel L, Klemm M, Baylacher M, Rizas KD, Bauer A, Brunner S. Deceleration Capacity of Heart Rate After Acute Altitude Exposure. High Alt Med Biol 2018; 19:299-302. [DOI: 10.1089/ham.2018.0041] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Wolfgang Hamm
- Medical Department I, Cardiology, Ludwig-Maximilian University Munich, Munich, Germany
- German Cardiovascular Research Center (DZHK), Partner Site: Munich Heart Alliance, Munich, Germany
| | - Lukas von Stülpnagel
- Medical Department I, Cardiology, Ludwig-Maximilian University Munich, Munich, Germany
- German Cardiovascular Research Center (DZHK), Partner Site: Munich Heart Alliance, Munich, Germany
| | - Mathias Klemm
- Medical Department I, Cardiology, Ludwig-Maximilian University Munich, Munich, Germany
- German Cardiovascular Research Center (DZHK), Partner Site: Munich Heart Alliance, Munich, Germany
| | - Monika Baylacher
- Medical Department I, Cardiology, Ludwig-Maximilian University Munich, Munich, Germany
| | - Konstantinos D. Rizas
- Medical Department I, Cardiology, Ludwig-Maximilian University Munich, Munich, Germany
- German Cardiovascular Research Center (DZHK), Partner Site: Munich Heart Alliance, Munich, Germany
| | - Axel Bauer
- Medical Department I, Cardiology, Ludwig-Maximilian University Munich, Munich, Germany
- German Cardiovascular Research Center (DZHK), Partner Site: Munich Heart Alliance, Munich, Germany
| | - Stefan Brunner
- Medical Department I, Cardiology, Ludwig-Maximilian University Munich, Munich, Germany
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Muza SR. Wearable physiological sensors and real-time algorithms for detection of acute mountain sickness. J Appl Physiol (1985) 2018; 124:557-563. [DOI: 10.1152/japplphysiol.00367.2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
This is a minireview of potential wearable physiological sensors and algorithms (process and equations) for detection of acute mountain sickness (AMS). Given the emerging status of this effort, the focus of the review is on the current clinical assessment of AMS, known risk factors (environmental, demographic, and physiological), and current understanding of AMS pathophysiology. Studies that have examined a range of physiological variables to develop AMS prediction and/or detection algorithms are reviewed to provide insight and potential technological roadmaps for future development of real-time physiological sensors and algorithms to detect AMS. Given the lack of signs and nonspecific symptoms associated with AMS, development of wearable physiological sensors and embedded algorithms to predict in the near term or detect established AMS will be challenging. Prior work using [Formula: see text], HR, or HRv has not provided the sensitivity and specificity for useful application to predict or detect AMS. Rather than using spot checks as most prior studies have, wearable systems that continuously measure SpO2 and HR are commercially available. Employing other statistical modeling approaches such as general linear and logistic mixed models or time series analysis to these continuously measured variables is the most promising approach for developing algorithms that are sensitive and specific for physiological prediction or detection of AMS.
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Affiliation(s)
- Stephen R. Muza
- Strategic Science Management Office, US Army Research Institute of Environmental Medicine, Natick, Massachusetts
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