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Shaw DM, Harrell JW. Integrating physiological monitoring systems in military aviation: a brief narrative review of its importance, opportunities, and risks. ERGONOMICS 2023; 66:2242-2254. [PMID: 36946542 DOI: 10.1080/00140139.2023.2194592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 03/18/2023] [Indexed: 06/18/2023]
Abstract
Military pilots risk their lives during training and operations. Advancements in aerospace engineering, flight profiles, and mission demands may require the pilot to test the safe limits of their physiology. Monitoring pilot physiology (e.g. heart rate, oximetry, and respiration) inflight is in consideration by several nations to inform pilots of reduced performance capacity and guide future developments in aircraft and life-support system design. Numerous challenges, however, prevent the immediate operationalisation of physiological monitoring sensors, particularly their unreliability in the aerospace environment and incompatibility with pilot clothing and protective equipment. Human performance and behaviour are also highly variable and measuring these in controlled laboratory settings do not mirror the real-world conditions pilots must endure. Misleading or erroneous predictive models are unacceptable as these could compromise mission success and lose operator trust. This narrative review provides an overview of considerations for integrating physiological monitoring systems within the military aviation environment.Practitioner summary: Advancements in military technology can conflictingly enhance and compromise pilot safety and performance. We summarise some of the opportunities, limitations, and risks of integrating physiological monitoring systems within military aviation. Our intent is to catalyse further research and technological development.Abbreviations: AGS: anti-gravity suit; AGSM: anti-gravity straining manoeuvre; A-LOC: almost loss of consciousness; CBF: cerebral blood flow; ECG: electrocardiogram; EEG: electroencephalogram; fNIRS: functional near-infrared spectroscopy; G-forces: gravitational forces; G-LOC: gravity-induced loss of consciousness; HR: heart rate; HRV: heart rate variability; LSS: life-support system; NATO: North Atlantic Treaty Organisation; PE: Physiological Episode; PCO2: partial pressure of carbon dioxide; PO2: partial pressure of oxygen; OBOGS: on board oxygen generating systems; SpO2: peripheral blood haemoglobin-oxygen saturation; STANAG: North Atlantic Treaty Organisation Standardisation Agreement; UPE: Unexplained Physiological Episode; WBV: whole body vibration.
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Affiliation(s)
- David M Shaw
- Aviation Medicine Unit, Royal New Zealand Air Force Base Auckland, Auckland, New Zealand
- School of Sport, Exercise and Nutrition, Massey University, Auckland, New Zealand
| | - John W Harrell
- 711th Human Performance Wing, Air Force Research Laboratory, Wright-Patterson Air Force Base, Dayton, OH, USA
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Ahmadian M, Ghasemi M, Nasrollahi Borujeni N, Afshan S, Fallah M, Ayaseh H, Pahlavan M, Nabavi Chashmi SM, Haeri T, Imani F, Zahedmanesh F, Akbari A, Nasiri K, Dabidi Roshan V. Does wearing a mask while exercising amid COVID-19 pandemic affect hemodynamic and hematologic function among healthy individuals? Implications of mask modality, sex, and exercise intensity. PHYSICIAN SPORTSMED 2022; 50:257-268. [PMID: 33902400 DOI: 10.1080/00913847.2021.1922947] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
OBJECTIVES We investigated how wearing a mask - and its modality (surgical vs. N95) - affect hemodynamic and hematologic function in males and females across two exercise intensities (submaximal (SUB) and maximal (MAX)). METHODS 144 individuals participated in the present study and were randomly allocated to three mask groups of 48 (N95, SURGICAL, and NO MASK) with two exercise subgroups for each mask group (MAX, n = 24; SUB, n = 24) for both sexes. Participants in each experimental group (N95SUB, N95MAX; SURSUB, SURMAX; SUB, MAX) were assessed for their hemodynamic and hematologic function at baseline and during recovery after exercise. RESULTS No significant differences were noted for either hemodynamic or hematologic function at post-exercise as compared to baseline with regard to mask modality (P > 0.05). Heart rate (HR) for maximal intensity were significantly greater at 1 min post-exercise in N95 as compared to SURGICAL (P < 0.05). No differences were noted for hemodynamic and hematologic function with N95 and SURGICAL compared to NOMASK for either intensity (P > 0.05). Females showed significantly greater HR values at 1 min post-exercise in N95 as compared to NO MASK, but no significant differences were noted for hematological function between sexes (P > 0.05). CONCLUSION Our findings show that wearing a face mask (N95/surgical) while exercising has no detrimental effects on hemodynamic/hematologic function in both males and females, and suggest that wearing a mask, particularly a surgical mask, while exercising during the ongoing pandemic is safe and poses no risk to individual's health. Future studies examining physiological responses to chronic exercise with masks are warranted.
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Affiliation(s)
- Mehdi Ahmadian
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
| | - Mohammad Ghasemi
- Department of Exercise Physiology, Faculty of Sport Science, University of Mazandaran, Babolsar, Iran
| | | | - Samaneh Afshan
- Department of Exercise Physiology, Faculty of Sport Science, University of Mazandaran, Babolsar, Iran
| | - Masoumeh Fallah
- Department of Exercise Physiology, Faculty of Sport Science, University of Mazandaran, Babolsar, Iran
| | - Hamed Ayaseh
- Department of Exercise Physiology, Faculty of Sport Science, University of Mazandaran, Babolsar, Iran
| | - Mohammad Pahlavan
- Department of Exercise Physiology, Faculty of Sport Science, University of Mazandaran, Babolsar, Iran
| | | | - Tahereh Haeri
- Department of Exercise Physiology, Faculty of Sport Science, University of Mazandaran, Babolsar, Iran
| | - Fattaneh Imani
- Department of Exercise Physiology, Faculty of Sport Science, University of Mazandaran, Babolsar, Iran
| | - Foruzan Zahedmanesh
- Department of Exercise Physiology, Faculty of Sport Science, University of Mazandaran, Babolsar, Iran
| | - Abolfazl Akbari
- Department of Physiology, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
| | - Khadijeh Nasiri
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
| | - Valiollah Dabidi Roshan
- Department of Exercise Physiology, Faculty of Sport Science, University of Mazandaran, Babolsar, Iran.,Athletic Performance and Health Research Center, Department of Exercise Physiology, Faculty of Sport Science, University of Mazandaran, Babolsar, Iran
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Nira Mat Isar NE, Zikri Abdul Halim MH, Ong MLY. Acute massage stimulates parasympathetic activation after a single exhaustive muscle contraction exercise. J Bodyw Mov Ther 2022; 30:105-111. [DOI: 10.1016/j.jbmt.2022.02.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 10/04/2021] [Accepted: 02/04/2022] [Indexed: 11/26/2022]
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Ivonina NI, Fokin AA, Roshchevskaya IM. Body Surface Potential Mapping During Heart Ventricular Repolarization in Male Swimmers and Untrained Persons Under Hypoxic and Hypercapnic Hypoxia. High Alt Med Biol 2021; 22:308-316. [PMID: 34314614 DOI: 10.1089/ham.2020.0103] [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
Ivonina, Natalya I., Andrey A. Fokin, and Irina M. Roshchevskaya. Body surface potential mapping during heart ventricular repolarization in male swimmers and untrained persons under hypoxic and hypercapnic hypoxia. High Alt Med Biol. 00:000-000, 2021. Background: In swimmers, as a result of prolonged breath-holding during swimming, first hypoxic hypoxia (HH) and then hypercapnic hypoxia (HCH) occurs, which may influence the electrical activity of the heart (EAH). What type of normobaric hypoxia more strongly affects the EAH-normocapnic HH or HCH? Methods: The electrical activity of swimmers' hearts (n = 7) and untrained persons (n = 10) was studied by using electrocardiography (ECG) and body surface potential mapping (BSPM) during the period of ventricular repolarization at baseline, at normocapnic HH, at HCH, and in the recovery period. Results: HH led to more significant changes in the EAH in all participants in comparison with HCH. There was no change in the amplitude of T waveECG at hypoxic and HCH, but a change in the amplitude of the minimum was noted in BSPM. The minimum in athletes changed by the end of the exposure (from -0.40 ± 0.12 mV to -0.26 ± 0.11 mV, p = 0.001); in the control, it decreased earlier (after 8 minutes of exposure to HH, the amplitude of the minimum was -0.24 ± 0.08 mV, p = 0.026). With HH, the duration of the QT interval in athletes was shortened due to the shortening of the J-Tpeak (from 250 to 188 ms, p = 0.001) and the Tpeak-Tend (from 98 to 86 ms) intervals. In controls, the decrease in the QT interval was due to the J-Tpeak shortening only (from 280 to 200 ms, p = 0.026). Conclusions: In the study of the effect of hypoxia on the EAH during ventricular repolarization, the use of the BSPM has proven to be more informative than the use of traditional ECG. When using potential mapping, more significant changes in ventricular repolarization at HH than at HCH were revealed, whereas the parameters changed less in swimmers compared with the baseline than in controls during both exposures.
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Affiliation(s)
- Natalya I Ivonina
- Department of Comparative Cardiology of the Federal Research Centre "Komi Science Centre of the Ural Branch of the Russian Academy of Sciences," Syktyvkar, Russian Federation
| | - Andrey A Fokin
- Department of Comparative Cardiology of the Federal Research Centre "Komi Science Centre of the Ural Branch of the Russian Academy of Sciences," Syktyvkar, Russian Federation
| | - Irina M Roshchevskaya
- Federal State Budgetary Institution "Research Zakusov Institute of Pharmacology," Moscow, Russian Federation
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Gultyaeva VV, Uryumtsev DY, Zinchenko MI, Melnikov VN, Balioz NV, Krivoschekov SG. Cardiorespiratory Coordination in Hypercapnic Test Before and After High-Altitude Expedition. Front Physiol 2021; 12:673570. [PMID: 34108888 PMCID: PMC8181754 DOI: 10.3389/fphys.2021.673570] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 04/16/2021] [Indexed: 12/12/2022] Open
Abstract
Coordination of cardiovascular and respiratory systems enables a wide range of human adaptation and depends upon the functional state of an individual organism. Hypoxia is known to elicit changes in oxygen and carbon dioxide sensitivity, while training alters cardiorespiratory coordination (CRC). The delayed effect of high altitude (HA) acclimatization on CRC in mountaineers remains unknown. The objective of this study was to compare CRC in acute hypercapnia in mountaineers before and after a HA expedition. Nine trained male mountaineers were investigated at sea level before (Pre-HA) and after a 20-day sojourn at altitudes of 4,000–7,000 m (Post-HA) in three states (Baseline, Hypercapnic Rebreathing, and Recovery). A principal component (PC) analysis was performed to evaluate the CRC. The number of mountaineers with one PC increased Post-HA (nine out of nine), compared to Pre-HA (five out of nine) [Chi-square (df = 1) = 5.14, P = 0.023]; the percentage of total variance explained by PC1 increased [Pre-HA median 65.6 (Q1 64.9/Q3 74.9), Post-HA 75.6 (73.3/77.9), P = 0.028]. Post-HA, the loadings of the expired fraction of O2, CO2, and ventilation onto PC1 did not change, and the loading of heart rate increased [Pre-HA 0.64 (0.45/0.68) and Post-HA 0.76 (0.65/0.82), P = 0.038]. During the Recovery, the percentage of total variance explained by PC1 was higher than during the Baseline. Post-HA, there was a high correlation between the Exercise addiction scores and the eigenvalues of PC1 (r = 0.9, P = 0.001). Thus, acute hypercapnic exposure reveals the Post-HA increase in cardiorespiratory coordination, which is highly related to the level of exercise addiction.
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Affiliation(s)
- Valentina V Gultyaeva
- Laboratory of Functional Reserves of Human Organism, Scientific Research Institute of Neurosciences and Medicine, Novosibirsk, Russia
| | - Dmitriy Y Uryumtsev
- Laboratory of Functional Reserves of Human Organism, Scientific Research Institute of Neurosciences and Medicine, Novosibirsk, Russia
| | - Margarita I Zinchenko
- Laboratory of Functional Reserves of Human Organism, Scientific Research Institute of Neurosciences and Medicine, Novosibirsk, Russia
| | - Vladimir N Melnikov
- Laboratory of Functional Reserves of Human Organism, Scientific Research Institute of Neurosciences and Medicine, Novosibirsk, Russia
| | - Natalia V Balioz
- Laboratory of Functional Reserves of Human Organism, Scientific Research Institute of Neurosciences and Medicine, Novosibirsk, Russia
| | - Sergey G Krivoschekov
- Laboratory of Functional Reserves of Human Organism, Scientific Research Institute of Neurosciences and Medicine, Novosibirsk, Russia
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Lan L, Cen Y, Jiang L, Miao H, Lu W. Risk Factors for the Development of Intraoperative Hypoxia in Patients Undergoing Nonintubated Video-Assisted Thoracic Surgery: A Retrospective Study from a Single Center. Med Sci Monit 2021; 27:e928965. [PMID: 33901163 PMCID: PMC8086517 DOI: 10.12659/msm.928965] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Background Nonintubated video-assisted thoracic surgery (NIVATS) has been demonstrated to be safe and effective in patients. However, the risk factors for intraoperative hypoxia are unclear. This retrospective study aimed to identify the risk factors for the development of intraoperative hypoxia in patients undergoing NIVATS. Material/Methods The study included patients who underwent NIVATS between January 2011 and December 2018. Intraoperative hypoxia was defined as SpO2 ≤93%. Risk factors for hypoxia were identified by binary logistic regression analysis, and the characteristic distribution of patients with and without hypoxia was elaborated. Results Of 2742 included patients, age, anesthesia method, the technical level of surgeons, stair-climbing ability, and type of thoracic procedure were associated with intraoperative hypoxia (P<0.05). The characteristics of patients with hypoxia were older age (P=0.011), higher body mass index and revised cardiac risk index level (P=0.033 and P=0.031), and lower composition of stair-climbing ≥22 m (P<0.001). These patients also had more anatomical lung surgery and mediastinal mass resection (P=0.033) and more epidural anesthesia (P=0.005). The surgeries were more likely to be performed by surgeons with less than 10 years of VATS training (P=0.009) and to have increased intraoperative maximum end-expiratory carbon dioxide partial pressure (P<0.001). These patients had a longer Intensive Care Unit stay (P<0.001), duration of chest-tube drainage (P=0.019), and postoperative hospitalization (P=0.003). Conclusions The current study suggests that old age and stair-climbing ability of patients, anesthesia method, thoracic procedures, and surgeon experience are risk factors for intraoperative hypoxia in patients undergoing NIVATS.
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Affiliation(s)
- Lan Lan
- Department of Anesthesiology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China (mainland)
| | - Yanyi Cen
- Department of Anesthesiology, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China (mainland)
| | - Long Jiang
- Department of Cardiothoracic Surgery, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China (mainland).,Guangzhou Institute of Respiratory Disease and China State Key Laboratory of Respiratory Disease, Guangzhou, Guangdong, China (mainland)
| | - Huazhang Miao
- Department of Healthcare, Guangdong Women and Children Hospital, Guangzhou, Guangdong, China (mainland)
| | - Weixiang Lu
- Department of Cardiothoracic Surgery, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China (mainland).,Guangzhou Institute of Respiratory Disease and China State Key Laboratory of Respiratory Disease, Guangzhou, Guangdong, China (mainland)
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Plant LD, Xiong D, Romero J, Dai H, Goldstein SAN. Hypoxia Produces Pro-arrhythmic Late Sodium Current in Cardiac Myocytes by SUMOylation of Na V1.5 Channels. Cell Rep 2021; 30:2225-2236.e4. [PMID: 32075761 PMCID: PMC7054841 DOI: 10.1016/j.celrep.2020.01.025] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 12/03/2019] [Accepted: 01/07/2020] [Indexed: 01/08/2023] Open
Abstract
Acute cardiac hypoxia produces life-threatening elevations in late sodium current (ILATE) in the human heart. Here, we show the underlying mechanism: hypoxia induces rapid SUMOylation of NaV1.5 channels so they reopen when normally inactive, late in the action potential. NaV1.5 is SUMOylated only on lysine 442, and the mutation of that residue, or application of a deSUMOylating enzyme, prevents hypoxic reopenings. The time course of SUMOylation of single channels in response to hypoxia coincides with the increase in ILATE, a reaction that is complete in under 100 s. In human cardiac myocytes derived from pluripotent stem cells, hypoxia-induced ILATE is confirmed to be SUMO-dependent and to produce action potential prolongation, the pro-arrhythmic change observed in patients. The cardiac channel NaV1.5 passes pro-arrhythmic late sodium currents in response to hypoxia. Plant et al. demonstrate the pathophysiological mechanism to be rapid, hypoxia-induced monoSUMOylation of NaV1.5 channels. Blocking SUMOylation of lysine442 prevents hypoxia-induced late currents and attendant prolongation of the action potential in human cardiomyocytes derived from pluripotent stem cells.
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Affiliation(s)
- Leigh D Plant
- Department of Pharmaceutical Sciences, Northeastern University, 360 Huntington Avenue, Boston, MA 02115, USA.
| | - Dazhi Xiong
- Departments of Pediatrics and Physiology & Biophysics, University of California, Irvine, 1001 Health Sciences Road, Irvine Hall, Irvine, CA 92697, USA
| | - Jesus Romero
- Departments of Pediatrics and Physiology & Biophysics, University of California, Irvine, 1001 Health Sciences Road, Irvine Hall, Irvine, CA 92697, USA
| | - Hui Dai
- Departments of Pediatrics and Physiology & Biophysics, University of California, Irvine, 1001 Health Sciences Road, Irvine Hall, Irvine, CA 92697, USA
| | - Steve A N Goldstein
- Departments of Pediatrics and Physiology & Biophysics, University of California, Irvine, 1001 Health Sciences Road, Irvine Hall, Irvine, CA 92697, USA.
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Martino PF, Miller DP, Miller JR, Allen MT, Cook-Snyder DR, Handy JD, Servatius RJ. Cardiorespiratory Response to Moderate Hypercapnia in Female College Students Expressing Behaviorally Inhibited Temperament. Front Neurosci 2020; 14:588813. [PMID: 33281546 PMCID: PMC7691270 DOI: 10.3389/fnins.2020.588813] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 10/26/2020] [Indexed: 11/19/2022] Open
Abstract
Behaviorally inhibited (BI) temperament is marked by heightened behavioral sensitivity to environmental threats. The degree to which threat sensitivity is reflected in cardiorespiratory responses has been relatively unexplored. Female college students were exposed to modest hypercapnia (7.0% CO2) or ambient air (AA) while engaging in a computerized task with cued reinforcement features. All physiological variables except for blood pressure were processed in 4 min epochs corresponding to pre-exposure, exposure, and post-exposure. Primary respiratory measures were respiratory frequency (fb), tidal volume (VT), and minute ventilation (VE). Electrocardiograms (ECGs) were processed using ARTiiFACT software with resultant heart rate variability (HRV) measures in the frequency domain and time domain. Consistent with the literature, modest hypercapnia increased VT, Fb, and VE. No differences in respiratory parameters were detected between BI and non-behaviorally inhibited individuals (NI). For HRV in the time domain, RMSSD and NN50 values increased during CO2 inhalation which then returned to pre-exposure levels after CO2 cessation. Hypercapnia increased high frequency (HF) power which then recovered. BI exhibited reduced low frequency (LF) power during the pre-exposure period. For NI, LF power reduced over the subsequent phases ameliorating differences between BI and NI. Hypercapnia improved the task performance of BI. This is the largest study of female reactivity to hypercapnia and associated HRV to date. In general, hypercapnia increased time domain HRV and HF power, suggesting a strong vagal influence. Those expressing BI exhibited similar respiratory and HRV reactivity to NI despite inherently reduced LF power. Although 7% CO2 represents a mild challenge to the respiratory and cardiovascular systems, it is nonetheless sufficient to explore inherent difference in stress reactivity in those vulnerable to develop anxiety disorders.
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Affiliation(s)
- Paul F Martino
- Biology Department, Carthage College, Kenosha, WI, United States.,Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Daniel P Miller
- Neuroscience Department, Carthage College, Kenosha, WI, United States
| | - Justin R Miller
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Michael T Allen
- School of Psychological Sciences, College of Education and Behavioral Sciences, University of Northern Colorado, Greeley, CO, United States
| | - Denise R Cook-Snyder
- Biology Department, Carthage College, Kenosha, WI, United States.,Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Justin D Handy
- Naval Submarine Medical Research Laboratory, Groton, CT, United States
| | - Richard J Servatius
- United States Department of Veterans Affairs, Syracuse VA Medical Center, Syracuse, NY, United States.,Department of Psychiatry, State University of New York Upstate Medical University, Syracuse, NY, United States
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Lee S, Li G, Liu T, Tse G. COVID-19: Electrophysiological mechanisms underlying sudden cardiac death during exercise with facemasks. Med Hypotheses 2020; 144:110177. [PMID: 33254499 PMCID: PMC7417258 DOI: 10.1016/j.mehy.2020.110177] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 08/09/2020] [Indexed: 02/06/2023]
Abstract
The mandatory use of facemasks is a public health measure implemented by various countries in response to the novel coronavirus disease 19 (COVID-19) pandemic. However, there have been case reports of sudden cardiac death (SCD) with the wearing of facemasks during exercise. In this paper, we hypothesize that exercise with facemasks may increase the risk of ventricular tachycardia/ventricular fibrillation (VT/VF) leading to SCD via the development of acute and/or intermittent hypoxia and hypercapnia. We discuss the potential underlying mechanisms including increases in adrenergic stimulation and oxidative stress leading to electrophysiological abnormalities that promote arrhythmias via non-reentrant and reentrant mechanisms. Given the interplay of multiple variables contributing to the increased arrhythmic risk, we advise avoidance of a facemask during high intensity exercise, or if wearing of a mask is mandatory, exercise intensity should remain low to avoid precipitation of lethal arrhythmias. However, we cannot exclude the possibility of an arrhythmic substrate even with low intensity exercise especially in those with established chronic cardiovascular disease in whom baseline electrophysiological abnormalities may be found.
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Affiliation(s)
- Sharen Lee
- Laboratory of Cardiovascular Physiology, Li Ka Shing Institute of Health Sciences, Hong Kong, China
| | - Guoliang Li
- Department of Cardiovascular Medicine, The First Affiliated Hospital of Xi'an Jiaotong University, 277 Yanta West Road, Xi'an 710061, China
| | - Tong Liu
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin 300211, China
| | - Gary Tse
- Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Department of Cardiology, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin 300211, China.
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Uryumtsev DY, Gultyaeva VV, Zinchenko MI, Baranov VI, Melnikov VN, Balioz NV, Krivoschekov SG. Effect of Acute Hypoxia on Cardiorespiratory Coherence in Male Runners. Front Physiol 2020; 11:630. [PMID: 32714198 PMCID: PMC7340006 DOI: 10.3389/fphys.2020.00630] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Accepted: 05/18/2020] [Indexed: 02/04/2023] Open
Abstract
Understanding the mechanisms of oxygen supply regulation, which involves the respiratory and cardiovascular systems, during human adaptation to intense physical activity, accompanied by hypoxemia, is important for the management of a training process. The objectives of this study were to investigate the cardiorespiratory coherence (CRC) changes in the low-frequency band in response to hypoxic exposure and to verify a dependence of these changes upon sports qualification level in athletes. Twenty male runners aged 17-25 years were exposed to acute normobaric hypoxia (10% O2) for 10 min. Respiration, gas exchange, and heart rate were measured at baseline, during hypoxia, and after the exposure. To evaluate cardiorespiratory coupling, squared coherence was calculated based on 5-s averaged time series of heart and respiratory rhythms. Based on sports qualification level achieved over 4 years after the experimental testing, athletes were retrospectively divided into two groups, one high level (HLG, n = 10) and the other middle level (MLG, n = 10). No differences in anthropometric traits were observed between the groups. In the pooled group, acute hypoxia significantly increased CRC at frequencies 0.030-0.045 Hz and 0.075 Hz. In response to hypoxia, oxygen consumption decreased in HLG, and carbon dioxide production and ventilation increased in MLG. At 0.070-0.080 Hz frequencies in hypoxia, the CRC in HLG was higher than in MLG. Thus, highly qualified athletes enhance intersystem integration in response to hypoxia. This finding can be a physiological sign for the prognosis of qualification level in runners.
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Affiliation(s)
| | - Valentina V. Gultyaeva
- Laboratory of Functional Reserves of Organism, Scientific Research Institute of Physiology and Basic Medicine, Novosibirsk, Russia
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Determining differences between critical closing pressure and resistance-area product: responses of the healthy young and old to hypocapnia. Pflugers Arch 2019; 471:1117-1126. [DOI: 10.1007/s00424-019-02290-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 05/31/2019] [Accepted: 06/05/2019] [Indexed: 10/26/2022]
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12
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Hermand E, Pichon A, Lhuissier FJ, Richalet JP. Low-frequency ventilatory oscillations in hypoxia are a major contributor to the low-frequency component of heart rate variability. Eur J Appl Physiol 2019; 119:1769-1777. [PMID: 31154522 DOI: 10.1007/s00421-019-04166-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 04/19/2019] [Accepted: 05/23/2019] [Indexed: 12/23/2022]
Abstract
PURPOSE Heart rate variability (HRV) may be influenced by several factors, such as environment (hypoxia, hyperoxia, hypercapnia) or physiological demand (exercise). In this retrospective study, we tested the hypothesis that inter-beat (RR) intervals in healthy subjects exercising under various environmental stresses exhibit oscillations at the same frequency than ventilatory oscillations. METHODS Spectra from RR intervals and ventilation ([Formula: see text]E) were collected from 37 healthy young male subjects who participated in 5 previous studies focused on ventilatory oscillations (or periodic breathing) during exercise in hypoxia, hyperoxia and hypercapnia. Bland and Altman test and multivariate regressions were then performed to compare respective frequencies and changes in peak powers of the two signals. RESULTS Fast Fourier analysis of RR and [Formula: see text]E signals showed that RR was oscillating at the same frequency than periodic breathing, i.e., ~ 0.09 Hz (11 s). During exercise, in these various conditions, the difference between minimum and maximum HRV peak power was positively correlated to the same change in ventilation peak power (P < 0.05). Low-frequency (LF) peak power was correlated to tidal volume (P < 0.01) and breathing frequency (P < 0.001). CONCLUSIONS This study suggests that low-frequency ventilatory oscillations in hypoxia are a major contributor to the LF band power of heart rate variability. CLINICAL TRIAL REG. NO.: NCT02201875.
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Affiliation(s)
- Eric Hermand
- Laboratoire HAVAE 'Handicap, Activité, Vieillissement, Autonomie, Environnement', E6310, Université de Limoges, Faculté Des Sciences Et Techniques, 123 avenue Albert Thomas, 87060, Limoges Cedex, France.
- Sorbonne Paris Cité, Laboratoire "Hypoxie & Poumon", E2363, Université Paris 13, Bobigny, France.
| | - Aurélien Pichon
- Laboratoire MOVE, Université de Poitiers, E6314, Poitiers, France
| | - François J Lhuissier
- Sorbonne Paris Cité, Laboratoire "Hypoxie & Poumon", E2363, Université Paris 13, Bobigny, France
- Assistance Publique-Hôpitaux de Paris, Hôpital Avicenne, Service de Physiologie, Explorations Fonctionnelles Et Médecine du Sport, 93009, Bobigny, France
| | - Jean-Paul Richalet
- Sorbonne Paris Cité, Laboratoire "Hypoxie & Poumon", E2363, Université Paris 13, Bobigny, France
- Département Médical, Institut National de L'Expertise Et de La Performance, 75012, Paris, France
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13
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McKeown DJ, Simmonds MJ, Kavanagh JJ. Reduced blood oxygen levels induce changes in low-threshold motor unit firing that align with the individual’s tolerance to hypoxia. J Neurophysiol 2019; 121:1664-1671. [DOI: 10.1152/jn.00071.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study aimed to quantify how acute hypoxia impacts firing characteristics of biceps brachii motor units (MUs) during sustained isometric elbow flexions. MU data were extracted from surface electromyography (EMG) during 25% maximal voluntary contractions (MVC) in 10 healthy subjects (age 22 ± 1 yr). Blood oxygen saturation (SpO2) was then stabilized at 80% by reducing 1% of the fraction of inspired oxygen every 3 min for 35 min. MU data were once again collected 1 h and 2 h following the 35-min desaturation phase. Although MVC remained unaffected during 2 h of 80% SpO2, subject-specific changes in MU firing rate were observed. Four of 10 subjects exhibited a decrease in firing rate 1 h postdesaturation (12 ± 11%) and 2 h postdesaturation (16 ± 12%), whereas 6 of 10 subjects exhibited an increase in firing rate 1 h (9 ± 6%) and 2 h (9 ± 4%) postdesaturation. These bidirectional changes in firing rate were strongly correlated to the desaturation phase and the subjects’ SpO2 sensitivity to oxygen availability, where subjects who had decreased firing rates reached the target SpO2 20 min into the desaturation phase ( R2 = 0.90–0.98) and those who had increased firing rates reached the target SpO2 35 min into the desaturation phase ( R2 = 0.87–0.98). It is unlikely that a single mechanism accounted for these subject-specific changes in firing rate. Instead, differences in intrinsic properties of the neurons, afferent input to the motoneurons, neuromodulators, and sympathetic nerve activity may exist between groups. NEW & NOTEWORTHY The mechanisms of compromised motor control when exposed to hypoxia are largely unknown. The current study examined how severe acute hypoxia affects motor unit firing rate during sustained isometric contractions of the bicep brachii. The response to hypoxia was different across subjects, where motor unit firing rate increased for some individuals and decreased for others. This bidirectional change in firing rate was associated with how fast subjects desaturated during hypoxic exposure.
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Affiliation(s)
- Daniel J. McKeown
- School of Allied Health Sciences, Menzies Health Institute Queensland, Griffith University, Gold Coast Campus, Queensland, Australia
| | - Michael J. Simmonds
- School of Allied Health Sciences, Menzies Health Institute Queensland, Griffith University, Gold Coast Campus, Queensland, Australia
| | - Justin J. Kavanagh
- School of Allied Health Sciences, Menzies Health Institute Queensland, Griffith University, Gold Coast Campus, Queensland, Australia
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14
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Lindsey BG, Nuding SC, Segers LS, Morris KF. Carotid Bodies and the Integrated Cardiorespiratory Response to Hypoxia. Physiology (Bethesda) 2019; 33:281-297. [PMID: 29897299 DOI: 10.1152/physiol.00014.2018] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Advances in our understanding of brain mechanisms for the hypoxic ventilatory response, coordinated changes in blood pressure, and the long-term consequences of chronic intermittent hypoxia as in sleep apnea, such as hypertension and heart failure, are giving impetus to the search for therapies to "erase" dysfunctional memories distributed in the carotid bodies and central nervous system. We review current network models, open questions, sex differences, and implications for translational research.
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Affiliation(s)
- Bruce G Lindsey
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
| | - Sarah C Nuding
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
| | - Lauren S Segers
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
| | - Kendall F Morris
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida , Tampa, Florida
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15
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Bourdillon N, Yazdani S, Subudhi AW, Lovering AT, Roach RC, Vesin JM, Kayser B. AltitudeOmics: Baroreflex Sensitivity During Acclimatization to 5,260 m. Front Physiol 2018; 9:767. [PMID: 29977210 PMCID: PMC6021743 DOI: 10.3389/fphys.2018.00767] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 05/31/2018] [Indexed: 11/13/2022] Open
Abstract
Introduction: Baroreflex sensitivity (BRS) is essential to ensure rapid adjustment to variations in blood pressure (BP). Little is known concerning the adaptive responses of BRS during acclimatization to high altitude at rest and during exercise. Methods: Twenty-one healthy sea-level residents were tested near sea level (SL, 130 m), the 1st (ALT1) and 16th day (ALT16) at 5,260 m using radial artery catheterization. BRS was calculated using the sequence method (direct interpretation of causal link between BP and heartrate). At rest, subjects breathed a hyperoxic mixture (250 mmHg O2, end tidal) to isolate the preponderance of CO2 chemoreceptors. End-tidal CO2 varied from 20 to 50 mmHg to assess peripheral chemoreflex. Rebreathing provoked incremental increase in CO2, increasing BP to assess baroreflex. During incremental cycling exercise to exhaustion, subjects breathed room air. Results: Resting BRS decreased in ALT1 which was exacerbated in ALT16. This decrease in ALT1 was reversible upon additional inspired CO2, but not in ALT16. BRS decrease during exercise was greater and occurred at lower workloads in ALT1 compared to SL. At ALT16, this decrease returned toward SL values. Discussion/Conclusion: This study is the first to report attenuated BRS in acute hypoxia, exacerbated in chronic hypoxia. In ALT1, hypocapnia triggered BRS reduction whilst in ALT16 resetting of chemoreceptor triggered BRS reduction. The exercise BRS resetting was impaired in ALT1 but normalized in ALT16. These BRS decreases indicate decreased control of BP and may explain deteriorations of cardiovascular status during exposure to high altitude.
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Affiliation(s)
- Nicolas Bourdillon
- Institute of Sports Sciences of the University of Lausanne, Lausanne, Switzerland
| | - Sasan Yazdani
- Applied Signal Processing Group, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Andrew W Subudhi
- Department of Biology, University of Colorado, Colorado Springs, CO, United States.,Altitude Research Center, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Andrew T Lovering
- Department of Human Physiology, University of Oregon, Eugene, OR, United States
| | - Robert C Roach
- Altitude Research Center, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Jean-Marc Vesin
- Applied Signal Processing Group, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Bengt Kayser
- Institute of Sports Sciences of the University of Lausanne, Lausanne, Switzerland
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