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Miyatsu T, Smith BM, Koutnik AP, Pirolli P, Broderick TJ. Resting-state heart rate variability after stressful events as a measure of stress tolerance among elite performers. Front Physiol 2023; 13:1070285. [PMID: 36685178 PMCID: PMC9848589 DOI: 10.3389/fphys.2022.1070285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 12/12/2022] [Indexed: 01/06/2023] Open
Abstract
Introduction: A common trait of elite performers is their ability to perform well when stressed by strong emotions such as fear. Developing objective measures of stress response that reliably predict performance under stress could have far-reaching implications in selection and training of elite individuals and teams. Prior data suggests that (i) Heart rate and heart rate variability (HR/HRV) are associated with stress reaction, (ii) Higher basal sympathetic tone prior to stressful events is associated with higher performance, and (iii) Elite performers tend to exhibit greater increase in parasympathetic tone after a stressful event. Methods: The current study assesses the predictive utility of post-stressful event HR/HRV measures, an under-studied time point in HR/HRV research, in the context of military personnel selection. Specifically, we examined the relationship between a comprehensive set of HR/HRV measures and established questionnaires related to stress tolerance, experimental evaluation of executive function during stress induction, and ecologically valid selection assessment data from a week-long Special Operations Forces selection course (N = 30). Results: We found that post-stressful event HR/HRV measures generally had strong correlations with the neuroticism facet of the NEO personality inventory as well as the general and distress facets of the defensive reactivity questionnaire. HR/HRV measures correlated reliably with a change in executive function measured as a decrease in verbal fluency with exposure to a well-validated stressor. Finally, we observed a divergent pattern of correlation among elite and non-elite SOF candidates. Specifically, among elite candidates, parasympathetic nervous system (PNS) measures correlated positively and sympathetic nervous system (SNS) measures correlated negatively with evaluation of stress tolerance by experts and peers. This pattern was not present in non-elite candidates. Discussion: Our findings demonstrate that post-stressful event HR/HRV data provide an objective non-invasive method to measure the recovery and arousal state in direct reaction to the stressful event and can be used as metrics of stress tolerance that could enhance selection of elite individuals and teams.
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Affiliation(s)
- Toshiya Miyatsu
- Healthspan Resilience & Performance, Florida Institute for Human and Machine Cognition, Pensacola, FL, United States,*Correspondence: Toshiya Miyatsu,
| | - Briana M. Smith
- Healthspan Resilience & Performance, Florida Institute for Human and Machine Cognition, Pensacola, FL, United States,Department of Bioengineering, University of Washington, Seattle, WA, United States
| | - Andrew P. Koutnik
- Healthspan Resilience & Performance, Florida Institute for Human and Machine Cognition, Pensacola, FL, United States
| | - Peter Pirolli
- Healthspan Resilience & Performance, Florida Institute for Human and Machine Cognition, Pensacola, FL, United States
| | - Timothy J. Broderick
- Healthspan Resilience & Performance, Florida Institute for Human and Machine Cognition, Pensacola, FL, United States
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Dean JB, Stavitzski NM. The O2-sensitive brain stem, hyperoxic hyperventilation, and CNS oxygen toxicity. Front Physiol 2022; 13:921470. [PMID: 35957982 PMCID: PMC9360621 DOI: 10.3389/fphys.2022.921470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 06/27/2022] [Indexed: 11/13/2022] Open
Abstract
Central nervous system oxygen toxicity (CNS-OT) is a complex disorder that presents, initially, as a sequence of cardio-respiratory abnormalities and nonconvulsive signs and symptoms (S/Sx) of brain stem origin that culminate in generalized seizures, loss of consciousness, and postictal cardiogenic pulmonary edema. The risk of CNS-OT and its antecedent “early toxic indications” are what limits the use of hyperbaric oxygen (HBO2) in hyperbaric and undersea medicine. The purpose of this review is to illustrate, based on animal research, how the temporal pattern of abnormal brain stem responses that precedes an “oxtox hit” provides researchers a window into the early neurological events underlying seizure genesis. Specifically, we focus on the phenomenon of hyperoxic hyperventilation, and the medullary neurons presumed to contribute in large part to this paradoxical respiratory response; neurons in the caudal Solitary complex (cSC) of the dorsomedial medulla, including putative CO2 chemoreceptor neurons. The electrophysiological and redox properties of O2-/CO2-sensitive cSC neurons identified in rat brain slice experiments are summarized. Additionally, evidence is summarized that supports the working hypothesis that seizure genesis originates in subcortical areas and involves cardio-respiratory centers and cranial nerve nuclei in the hind brain (brainstem and cerebellum) based on, respectively, the complex temporal pattern of abnormal cardio-respiratory responses and various nonconvulsive S/Sx that precede seizures during exposure to HBO2.
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Baran R, Marchal S, Garcia Campos S, Rehnberg E, Tabury K, Baselet B, Wehland M, Grimm D, Baatout S. The Cardiovascular System in Space: Focus on In Vivo and In Vitro Studies. Biomedicines 2021; 10:59. [PMID: 35052739 PMCID: PMC8773383 DOI: 10.3390/biomedicines10010059] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 12/24/2021] [Accepted: 12/25/2021] [Indexed: 12/13/2022] Open
Abstract
On Earth, humans are subjected to a gravitational force that has been an important determinant in human evolution and function. During spaceflight, astronauts are subjected to several hazards including a prolonged state of microgravity that induces a myriad of physiological adaptations leading to orthostatic intolerance. This review summarises all known cardiovascular diseases related to human spaceflight and focusses on the cardiovascular changes related to human spaceflight (in vivo) as well as cellular and molecular changes (in vitro). Upon entering microgravity, cephalad fluid shift occurs and increases the stroke volume (35-46%) and cardiac output (18-41%). Despite this increase, astronauts enter a state of hypovolemia (10-15% decrease in blood volume). The absence of orthostatic pressure and a decrease in arterial pressures reduces the workload of the heart and is believed to be the underlying mechanism for the development of cardiac atrophy in space. Cellular and molecular changes include altered cell shape and endothelial dysfunction through suppressed cellular proliferation as well as increased cell apoptosis and oxidative stress. Human spaceflight is associated with several cardiovascular risk factors. Through the use of microgravity platforms, multiple physiological changes can be studied and stimulate the development of appropriate tools and countermeasures for future human spaceflight missions in low Earth orbit and beyond.
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Affiliation(s)
- Ronni Baran
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, 8000 Aarhus, Denmark; (R.B.); (D.G.)
| | - Shannon Marchal
- Department of Astronomy, Catholic University of Leuven, 3000 Leuven, Belgium;
- Radiobiology Unit, Belgian Nuclear Research Centre (SCK CEN), Boeretang 200, 2400 Mol, Belgium; (E.R.); (K.T.); (B.B.)
| | - Sebastian Garcia Campos
- Department of Microgravity and Translational Regenerative Medicine, Otto von Guericke University, Universitätsplatz 2, 39106 Magdeburg, Germany; (S.G.C.); (M.W.)
- Research Group ‘Magdeburger Arbeitsgemeinschaft für Forschung unter Raumfahrt- und Schwerelosigkeitsbedingungen’ (MARS), Otto von Guericke University, Universitätsplatz 2, 39106 Magdeburg, Germany
| | - Emil Rehnberg
- Radiobiology Unit, Belgian Nuclear Research Centre (SCK CEN), Boeretang 200, 2400 Mol, Belgium; (E.R.); (K.T.); (B.B.)
- Department of Molecular Biotechnology, Ghent University, 9000 Ghent, Belgium
| | - Kevin Tabury
- Radiobiology Unit, Belgian Nuclear Research Centre (SCK CEN), Boeretang 200, 2400 Mol, Belgium; (E.R.); (K.T.); (B.B.)
- Department of Biomedical Engineering, University of South Carolina, Columbia, SC 29208, USA
| | - Bjorn Baselet
- Radiobiology Unit, Belgian Nuclear Research Centre (SCK CEN), Boeretang 200, 2400 Mol, Belgium; (E.R.); (K.T.); (B.B.)
| | - Markus Wehland
- Department of Microgravity and Translational Regenerative Medicine, Otto von Guericke University, Universitätsplatz 2, 39106 Magdeburg, Germany; (S.G.C.); (M.W.)
- Research Group ‘Magdeburger Arbeitsgemeinschaft für Forschung unter Raumfahrt- und Schwerelosigkeitsbedingungen’ (MARS), Otto von Guericke University, Universitätsplatz 2, 39106 Magdeburg, Germany
| | - Daniela Grimm
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, 8000 Aarhus, Denmark; (R.B.); (D.G.)
- Department of Microgravity and Translational Regenerative Medicine, Otto von Guericke University, Universitätsplatz 2, 39106 Magdeburg, Germany; (S.G.C.); (M.W.)
- Research Group ‘Magdeburger Arbeitsgemeinschaft für Forschung unter Raumfahrt- und Schwerelosigkeitsbedingungen’ (MARS), Otto von Guericke University, Universitätsplatz 2, 39106 Magdeburg, Germany
| | - Sarah Baatout
- Department of Astronomy, Catholic University of Leuven, 3000 Leuven, Belgium;
- Radiobiology Unit, Belgian Nuclear Research Centre (SCK CEN), Boeretang 200, 2400 Mol, Belgium; (E.R.); (K.T.); (B.B.)
- Department of Molecular Biotechnology, Ghent University, 9000 Ghent, Belgium
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