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The effects of normobaric and hypobaric hypoxia on cognitive performance and physiological responses: A crossover study. PLoS One 2022; 17:e0277364. [DOI: 10.1371/journal.pone.0277364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 10/25/2022] [Indexed: 11/12/2022] Open
Abstract
This partially randomised controlled, crossover study sought to investigate the effects of normobaric hypoxia (NH) and hypobaric hypoxia (HH) on cognitive performance, the physiological response at rest and after a 3-min step-test. Twenty healthy participants (10 females and 10 males, 27.6±6.2yrs, 73.6±13.7kg, 175.3±8.9cm) completed a cognitive performance test, followed by the modified Harvard-step protocol, in four environments: normobaric normoxia (NN; PiO2: 146.0±1.5mmHg), NH (PiO2: 100.9±1.3mmHg), HH at the first day of ascent (HH1: PiO2 = 105.6±0.4mmHg) and HH after an overnight stay (HH2: PiO2 = 106.0±0.5mmHg). At rest and/or exercise, SpO2, NIRS, and cardiovascular and perceptual data were collected. The cerebral tissue oxygenation index and the cognitive performance (throughput, accuracy, and reaction time) were not different between the hypoxic conditions (all p>0.05). In NH, SpO2 was higher compared to HH1 (ΔSpO2 NH vs HH1: 1.7±0.5%, p = 0.003) whilst heart rate (ΔHR NH vs HH2: 5.8±2.6 bpm, p = 0.03) and sympathetic activation (ΔSNSi NH vs HH2: 0.8±0.4, p = 0.03) were lower in NH compared to HH2. Heart rate (ΔHR HH1 vs HH2: 6.9±2.6 bpm, p = 0.01) and sympathetic action (ΔSNSi HH1 vs HH2: 0.9±0.4, p = 0.02) were both lower in HH1 compared to HH2. In conclusion, cognitive performance and cerebral oxygenation didn’t differ between the hypoxic conditions. SpO2 was only higher in NH compared to HH1. In HH2, heart rate and sympathetic activation were higher compared to both NH and HH1. These conclusions account for a PiO2 between 100–106 mmHg.
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Ellenberger C, Pelosi P, de Abreu MG, Wrigge H, Diaper J, Hagerman A, Adam Y, Schultz MJ, Licker M. Distribution of ventilation and oxygenation in surgical obese patients ventilated with high versus low positive end-expiratory pressure: A substudy of a randomised controlled trial. Eur J Anaesthesiol 2022; 39:875-884. [PMID: 36093886 PMCID: PMC9553219 DOI: 10.1097/eja.0000000000001741] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
BACKGROUND Intra-operative ventilation using low/physiological tidal volume and positive end-expiratory pressure (PEEP) with periodic alveolar recruitment manoeuvres (ARMs) is recommended in obese surgery patients. OBJECTIVES To investigate the effects of PEEP levels and ARMs on ventilation distribution, oxygenation, haemodynamic parameters and cerebral oximetry. DESIGN A substudy of a randomised controlled trial. SETTING Tertiary medical centre in Geneva, Switzerland, between 2015 and 2018. PATIENTS One hundred and sixty-two patients with a BMI at least 35 kg per square metre undergoing elective open or laparoscopic surgery lasting at least 120 min. INTERVENTION Patients were randomised to PEEP of 4 cmH 2 O ( n = 79) or PEEP of 12 cmH 2 O with hourly ARMs ( n = 83). MAIN OUTCOME MEASURES The primary endpoint was the fraction of ventilation in the dependent lung as measured by electrical impedance tomography. Secondary endpoints were the oxygen saturation index (SaO 2 /FIO 2 ratio), respiratory and haemodynamic parameters, and cerebral tissue oximetry. RESULTS Compared with low PEEP, high PEEP was associated with smaller intra-operative decreases in dependent lung ventilation [-11.2%; 95% confidence interval (CI) -8.7 to -13.7 vs. -13.9%; 95% CI -11.7 to -16.5; P = 0.029], oxygen saturation index (-49.6%; 95% CI -48.0 to -51.3 vs. -51.3%; 95% CI -49.6 to -53.1; P < 0.001) and a lower driving pressure (-6.3 cmH 2 O; 95% CI -5.7 to -7.0). Haemodynamic parameters did not differ between the groups, except at the end of ARMs when arterial pressure and cardiac index decreased on average by -13.7 mmHg (95% CI -12.5 to -14.9) and by -0.54 l min -1 m -2 (95% CI -0.49 to -0.59) along with increased cerebral tissue oximetry (3.0 and 3.2% on left and right front brain, respectively). CONCLUSION In obese patients undergoing abdominal surgery, intra-operative PEEP of 12 cmH 2 O with periodic ARMs, compared with intra-operative PEEP of 4 cmH 2 O without ARMs, slightly redistributed ventilation to dependent lung zones with minor improvements in peripheral and cerebral oxygenation. TRIAL REGISTRATION NCT02148692, https://clinicaltrials.gov/ct2.
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Affiliation(s)
- Christoph Ellenberger
- From the Department of Anaesthesia, Pharmacology, Intensive Care and Emergency Medicine, University Hospital of Geneva, rue Gabriel-Perret-Gentil (CE, JD, AH, YA, ML), Faculty of Medicine, University of Geneva, Geneva, Switzerland (CE, ML), Department of Surgical Sciences and Integrated Diagnostics, University of Genoa (PP), Anaesthesia and Intensive Care, San Martino Policlinico Hospital, IRCCS for Oncology and Neurosciences, Genoa, Italy (PP), Pulmonary Engineering Group, Department of Anaesthesiology and Intensive Care Medicine, University Hospital Carl Gustav Carus, Dresden, Germany (MGdA), Department of Outcomes Research (MGdA), Department of Intensive Care and Resuscitation, Anesthesiology Institute, Cleveland Clinic, Cleveland, Ohio, USA (MGdA), Department of Anaesthesiology, Intensive Care and Emergency Medicine, Pain Therapy, Bergmannstrost Hospital (HW), Medical Faculty, Martin-Luther-University Halle-Wittenberg, Halle, Germany (HW), Department of Intensive Care & Laboratory of Experimental Intensive Care and Anesthesiology, Amsterdam University Medical Centers, Amsterdam, The Netherlands (MJS)
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Harbour E, Stöggl T, Schwameder H, Finkenzeller T. Breath Tools: A Synthesis of Evidence-Based Breathing Strategies to Enhance Human Running. Front Physiol 2022; 13:813243. [PMID: 35370762 PMCID: PMC8967998 DOI: 10.3389/fphys.2022.813243] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 01/28/2022] [Indexed: 01/23/2023] Open
Abstract
Running is among the most popular sporting hobbies and often chosen specifically for intrinsic psychological benefits. However, up to 40% of runners may experience exercise-induced dyspnoea as a result of cascading physiological phenomena, possibly causing negative psychological states or barriers to participation. Breathing techniques such as slow, deep breathing have proven benefits at rest, but it is unclear if they can be used during exercise to address respiratory limitations or improve performance. While direct experimental evidence is limited, diverse findings from exercise physiology and sports science combined with anecdotal knowledge from Yoga, meditation, and breathwork suggest that many aspects of breathing could be improved via purposeful strategies. Hence, we sought to synthesize these disparate sources to create a new theoretical framework called “Breath Tools” proposing breathing strategies for use during running to improve tolerance, performance, and lower barriers to long-term enjoyment.
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Affiliation(s)
- Eric Harbour
- Department of Sport and Exercise Science, University of Salzburg, Salzburg, Austria
- *Correspondence: Eric Harbour,
| | - Thomas Stöggl
- Department of Sport and Exercise Science, University of Salzburg, Salzburg, Austria
- Red Bull Athlete Performance Center, Salzburg, Austria
| | - Hermann Schwameder
- Department of Sport and Exercise Science, University of Salzburg, Salzburg, Austria
| | - Thomas Finkenzeller
- Department of Sport and Exercise Science, University of Salzburg, Salzburg, Austria
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Irisin Is Correlated with Blood Pressure in Obstructive Sleep Apnea Patients. Int J Hypertens 2021; 2021:4717349. [PMID: 34804606 PMCID: PMC8601862 DOI: 10.1155/2021/4717349] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 10/27/2021] [Indexed: 01/05/2023] Open
Abstract
Background Despite approximately 95% primary cases of hypertension, secondary hypertension seems to be common with resistant forms. Notably, obstructive sleep apnea (OSA) is known as a common cause of secondary hypertension and has a major characteristic of obesity. Irisin acts as a link between muscles and adipose tissues in obesity, playing an essential role in human blood pressure (BP) regulation. However, whether irisin is associated with secondary hypertension caused by OSA and how it takes effect essentially have not been elucidated. Purpose To investigate the changes of irisin and its relationship with BP in OSA. Methods 72 snoring patients finished Epworth Sleep Scale (ESS) evaluation before polysomnography (PSG). BP was the average of three brachial BP values by mercury sphygmomanometer. Serum irisin level was determined by enzyme-linked immunosorbent assay (ELISA). Results were analyzed by SPSS software. Results Irisin was higher in the severe and quite severe group than that in control and nonsevere groups (p < 0.05). For BP, significant differences were found between the control group and the other three groups (p < 0.05) and between the quite severe and the other three groups (p ≤ 0.001). Positive correlations were found between irisin and apnea-hypopnea index (AHI), AHI and BP, and irisin level and BP. Negative correlations were between irisin and SpO2 nadir and SpO2 nadir and BP. Positive correlation still existed between AHI and irisin even after adjusting for some obesity-related variables. Conclusions Irisin may serve as a potential biomarker for severity of OSA independently of obesity and imply the development of hypertension.
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Rupp T, Maufrais C, Walther G, Esteve F, Macdonald JH, Bouzat P, Verges S. MEDEX 2015: Prophylactic Effects of Positive Expiratory Pressure in Trekkers at Very High Altitude. Front Physiol 2021; 12:710622. [PMID: 34621182 PMCID: PMC8490760 DOI: 10.3389/fphys.2021.710622] [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: 05/16/2021] [Accepted: 08/31/2021] [Indexed: 11/13/2022] Open
Abstract
Purpose: Positive expiratory pressure (PEP) breathing has been shown to increase arterial oxygenation during acute hypoxic exposure but the underlying mechanisms and consequences on symptoms during prolonged high-altitude exposure remain to be elucidated. Methods: Twenty-four males (41 ± 16 years) were investigated, at sea level and at 5,085 m after 18 days of trekking from 570 m. Participants breathed through a face-mask with PEP = 0 cmH2O (PEP0, 0-45th min) and with PEP = 10 cmH2O (PEP10, 46-90th min). Arterial (SpO2), quadriceps and prefrontal (near infrared spectroscopy) oxygenation was measured continuously. Middle cerebral artery blood velocity (MCAv, transcranial Doppler), cardiac function (2D-echocardiography), extravascular lung water accumulation (UsLC, thoracic ultrasound lung comets) and acute mountain sickness (Lake Louise score, LLS) were assessed during PEP0 and PEP10. Results: At 5,085 m with PEP0, SpO2 was 78 ± 4%, UsLC was 8 ± 5 (a.u.) and the LLS was 2.3 ± 1.7 (all P < 0.05 versus sea level). At 5,085 m, PEP10 increased significantly SpO2 (+9 ± 5%), quadriceps (+2 ± 2%) and prefrontal cortex (+2 ± 2%) oxygenation (P < 0.05), and decreased significantly MCAv (-16 ± 14 cm.s-1) and cardiac output (-0.7 ± 1.2 L.min-1) together with a reduced stroke volume (-9 ± 15 mL, all P < 0.05) and no systemic hypotension. PEP10 decreased slightly the number of UsLC (-1.4 ± 2.7, P = 0.04) while the incidence of acute mountain sickness (LLS ≥ 3) fell from 42% with PEP0 to 25% after PEP10 (P = 0.043). Conclusion: PEP10 breathing improved arterial and tissue oxygenation and symptoms of acute mountain sickness after trekking to very high altitude, despite reduced cerebral perfusion and cardiac output. Further studies are required to establish whether PEP-breathing prophylactic mechanisms also occur in participants with more severe acute mountain sickness.
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Affiliation(s)
- Thomas Rupp
- Inter-University Laboratory of Human Movement Science (LIBM), University Savoie Mont Blanc, Chambéry, France
| | - Claire Maufrais
- Laboratoire de Pharm-Ecologie Cardiorespiratoire (LAPEC EA4278), Avignon University, Avignon, France.,HP2 Laboratory, INSERM, Grenoble Alpes University, Grenoble, France
| | - Guillaume Walther
- Laboratoire de Pharm-Ecologie Cardiorespiratoire (LAPEC EA4278), Avignon University, Avignon, France
| | - François Esteve
- RSRM EA7442, ID17-ESRF, Grenoble Alpes University, Grenoble, France
| | - Jamie Hugo Macdonald
- Extremes Research Group, School of Sport, Health and Exercise Sciences, Bangor University, Bangor, United Kingdom
| | - Pierre Bouzat
- Pôle Anesthésie Réanimation, Grenoble Alpes University Hospital, Grenoble, France
| | - Samuel Verges
- HP2 Laboratory, INSERM, Grenoble Alpes University, Grenoble, France
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Carr J, Stone R, Tymko C, Tymko K, Coombs GB, Hoiland RL, Howe CA, Tymko MM, Ainslie PN, Patrician A. Global REACH 2018: The Effect of an Expiratory Resistance Mask with Dead Space on Sleep and Acute Mountain Sickness During Acute Exposure to Hypobaric Hypoxia. High Alt Med Biol 2020; 21:297-302. [DOI: 10.1089/ham.2019.0124] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Affiliation(s)
- Jay Carr
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia–Okanagan Campus, Kelowna, Canada
| | - Rachel Stone
- Department of Kinesiology, University of Windsor, Windsor, Canada
| | - Courtney Tymko
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia–Okanagan Campus, Kelowna, Canada
| | - Kaitlyn Tymko
- Department of Kinesiology, University of Manitoba, Winnipeg, Canada
| | - Geoff B. Coombs
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia–Okanagan Campus, Kelowna, Canada
| | - Ryan L. Hoiland
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia–Okanagan Campus, Kelowna, Canada
- Department of Anaesthesiology, Pharmacology, and Therapeutics, Vancouver General Hospital, University of British Columbia, Vancouver, Canada
| | - Connor A. Howe
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia–Okanagan Campus, Kelowna, Canada
| | - Michael M. Tymko
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia–Okanagan Campus, Kelowna, Canada
| | - Philip N. Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia–Okanagan Campus, Kelowna, Canada
| | - Alexander Patrician
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia–Okanagan Campus, Kelowna, Canada
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Cardio-respiratory, oxidative stress and acute mountain sickness responses to normobaric and hypobaric hypoxia in prematurely born adults. Eur J Appl Physiol 2020; 120:1341-1355. [PMID: 32270264 DOI: 10.1007/s00421-020-04366-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 04/04/2020] [Indexed: 10/24/2022]
Abstract
PURPOSE We compared the effects of hypobaric and normobaric hypoxia on select cardio-respiratory responses, oxidative stress and acute mountain sickness (AMS) severity in prematurely born individuals, known to exhibit blunted hypoxic ventilatory response. METHODS Sixteen prematurely born but otherwise healthy males underwent two 8-h hypoxic exposures under: (1) hypobaric hypoxic [HH; terrestrial altitude 3840 m; PiO2:90.2 (0.5) mmHg; BP: 478 (2) mmHg] and (2) normobaric hypoxic [NH; PiO2:90.6 (0.9) mmHg; FiO2:0.142 (0.001)] condition. Resting values of capillary oxyhemoglobin saturation (SpO2), heart rate (HR) and blood pressure were measured before and every 2 h during the exposures. Ventilatory responses and middle cerebral artery blood flow velocity (MCAv) were assessed at rest and during submaximal cycling before and at 4 and 8 h. Plasmatic levels of selected oxidative stress and antioxidant markers and AMS symptoms were also determined at these time points. RESULTS HH resulted in significantly lower resting (P = 0.010) and exercise (P = 0.004) SpO2 as compared to NH with no significant differences in the ventilatory parameters, HR or blood pressure. No significant differences between conditions were found in resting or exercising MCAv and measured oxidative stress markers. Significantly lower values of ferric-reducing antioxidant power (P = 0.037) were observed during HH as opposed to NH. AMS severity was higher at 8 h compared to baseline (P = 0.002) with no significant differences between conditions. CONCLUSION These data suggest that, in prematurely born adults, 8-h exposure to hypobaric, as opposed to normobaric hypoxia, provokes greater reductions in systemic oxygenation and antioxidant capacity. Further studies investigating prolonged hypobaric exposures in this population are warranted. REGISTRATION NCT02780908 (ClinicalTrials.gov).
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Millet GP, Debevec T. Rebuttal from Grégoire P. Millet and Tadej Debevec. J Physiol 2020; 598:901-902. [PMID: 32053210 DOI: 10.1113/jp279425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Grégoire P Millet
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Tadej Debevec
- Faculty of Sport, University of Ljubljana, Ljubljana, Slovenia.,Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia.,School of Life sciences, Faculty of Medicine and Health Sciences, Nottingham University, Nottingham, UK
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Richalet JP. CrossTalk opposing view: Barometric pressure, independent of P O 2 , is not the forgotten parameter in altitude physiology and mountain medicine. J Physiol 2020; 598:897-899. [PMID: 32053235 DOI: 10.1113/jp279160] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Affiliation(s)
- Jean-Paul Richalet
- Université Paris 13, INSERM 1272 Hypoxie et poumon, Bobigny, France.,INSEP, Pôle medical, Paris, France
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Millet GP, Debevec T. CrossTalk proposal: Barometric pressure, independent of , is the forgotten parameter in altitude physiology and mountain medicine. J Physiol 2020; 598:893-896. [DOI: 10.1113/jp278673] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
| | - Tadej Debevec
- Faculty of SportUniversity of Ljubljana Ljubljana Slovenia
- Department of AutomationBiocybernetics and RoboticsJozef Stefan Institute Ljubljana Slovenia
- School of Life sciencesFaculty of Medicine and Health SciencesNottingham University Nottingham UK
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