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Yang S, Wu YR, Zhan Z, Pan YH, Jiang JF. State- and frequency-dependence in autonomic rebalance mediated by intradermal auricular electroacupuncture stimulation. Front Neurosci 2024; 18:1367266. [PMID: 38846714 PMCID: PMC11153749 DOI: 10.3389/fnins.2024.1367266] [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: 01/08/2024] [Accepted: 05/09/2024] [Indexed: 06/09/2024] Open
Abstract
Background Vagus nerve stimulation (VNS) improves diseases such as refractory epilepsy and treatment-resistant depression, likely by rebalancing the autonomic nervous system (ANS). Intradermal auricular electro-acupuncture stimulation (iaES) produces similar effects. The aim of this study was to determine the effects of different iaES frequencies on the parasympathetic and sympathetic divisions in different states of ANS imbalance. Methods We measured heart rate variability (HRV) and heart rate (HR) of non-modeled (normal) rats with the treatment of various frequencies to determine the optimal iaES frequency. The optimized iaES frequency was then applied to ANS imbalance model rats to elucidate its effects. Results 30 Hz and 100 Hz iaES clearly affected HRV and HR in normal rats. 30 Hz iaES increased HRV, and decreased HR. 100 Hz iaES decreased HRV, and increased HR. In sympathetic excited state rats, 30 Hz iaES increased HRV. 100 Hz iaES increased HRV, and decreased HR. In parasympathetic excited state rats, 30 Hz and 100 Hz iaES decreased HRV. In sympathetic inhibited state rats, 30 Hz iaES decreased HRV, while 100 Hz iaES decreased HR. In parasympathetic inhibited rats, 30 Hz iaES decreased HR and 100 Hz iaES increased HRV. Conclusion 30 Hz and 100 Hz iaES contribute to ANS rebalance by increasing vagal and sympathetic activity with different amplifications. The 30 Hz iaES exhibited positive effects in all the imbalanced states. 100 Hz iaES suppressed the sympathetic arm in sympathetic excitation and sympathetic/parasympathetic inhibition and suppressed the vagal arm and promoted the sympathetic arm in parasympathetic excitation and normal states.
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Affiliation(s)
| | | | | | | | - Jin-Feng Jiang
- Key Laboratory of Acupuncture and Medicine Research of Ministry of Education, Nanjing University of Chinese Medicine, Nanjing, China
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Giunta S, Xia S, Pelliccioni G, Olivieri F. Autonomic nervous system imbalance during aging contributes to impair endogenous anti-inflammaging strategies. GeroScience 2024; 46:113-127. [PMID: 37821752 PMCID: PMC10828245 DOI: 10.1007/s11357-023-00947-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 09/13/2023] [Indexed: 10/13/2023] Open
Abstract
Inflammaging refers to the age-related low grade, sterile, chronic, systemic, and long-lasting subclinical, proinflammatory status, currently recognized as the main risk factor for development and progression of the most common age-related diseases (ARDs). Extensive investigations were focused on a plethora of proinflammatory stimuli that can fuel inflammaging, underestimating and partly neglecting important endogenous anti-inflammaging mechanisms that could play a crucial role in such age-related proinflammatory state. Studies on autonomic nervous system (ANS) functions during aging highlighted an imbalance toward an overactive sympathetic nervous system (SNS) tone, promoting proinflammatory conditions, and a diminished parasympathetic nervous system (PNS) activity, playing anti-inflammatory effects mediated by the so called cholinergic anti-inflammatory pathway (CAP). At the molecular level, CAP is characterized by signals communicated via the vagus nerve (with the possible involvement of the splenic nerves) through acetylcholine release to downregulate the inflammatory actions of macrophages, key players of inflammaging. Notably, decreased vagal function and increased burden of activated/senescent macrophages (macrophaging) probably precede the development of several age-related risk factors and diseases, while increased vagal function and reduced macrophaging could be associated with relevant reduction of risk profiles. Hypothalamic-pituitary-adrenal axis (HPA axis) is another pathway related to ANS promoting some anti-inflammatory response mainly through increased cortisol levels. In this perspective review, we highlighted that CAP and HPA, representing broadly "anti-inflammaging" mechanisms, have a reduced efficacy and lose effectiveness in aged people, a phenomenon that could contribute to fuel inflammaging. In this framework, strategies aimed to re-balance PNS/SNS activities could be explored to modulate systemic inflammaging especially at an early subclinical stage, thus increasing the chances to reach the extreme limit of human lifespan in healthy status.
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Affiliation(s)
- Sergio Giunta
- Casa Di Cura Prof. Nobili (Gruppo Garofalo (GHC)), Castiglione Dei Pepoli, Bologna, Italy
| | - Shijin Xia
- Department of Geriatrics, Shanghai Institute of Geriatrics, Huadong Hospital, Fudan University, Shanghai, China
| | | | - Fabiola Olivieri
- Department of Clinical and Molecular Sciences, DISCLIMO, Università Politecnica Delle Marche, Via Tronto 10/A, 60126, Ancona, Italy.
- Clinical Laboratory and Molecular Diagnostic, IRCCS INRCA, Ancona, Italy.
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3
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Nicolini P, Malfatto G, Lucchi T. Heart Rate Variability and Cognition: A Narrative Systematic Review of Longitudinal Studies. J Clin Med 2024; 13:280. [PMID: 38202287 PMCID: PMC10780278 DOI: 10.3390/jcm13010280] [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: 11/05/2023] [Revised: 12/23/2023] [Accepted: 12/27/2023] [Indexed: 01/12/2024] Open
Abstract
BACKGROUND Heart rate variability (HRV) is a reliable and convenient method to assess autonomic function. Cross-sectional studies have established a link between HRV and cognition. Longitudinal studies are an emerging area of research with important clinical implications in terms of the predictive value of HRV for future cognition and in terms of the potential causal relationship between HRV and cognition. However, they have not yet been the objective of a systematic review. Therefore, the aim of this systematic review was to investigate the association between HRV and cognition in longitudinal studies. METHODS The review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The Embase, PsycINFO and PubMed databases were searched from the earliest available date to 26 June 2023. Studies were included if they involved adult human subjects and evaluated the longitudinal association between HRV and cognition. The risk of bias was assessed with the Newcastle-Ottawa Scale for Cohort Studies. The results were presented narratively. RESULTS Of 14,359 records screened, 12 studies were included in this systematic review, with a total of 24,390 participants. Two thirds of the studies were published from 2020 onwards. All studies found a longitudinal relationship between HRV and cognition. There was a consistent association between higher parasympathetic nervous system (PNS) activity and better cognition, and some association between higher sympathetic nervous system activity and worse cognition. Also, higher PNS activity persistently predicted better executive functioning, while data on episodic memory and language were more scant and/or controversial. CONCLUSIONS Our results support the role of HRV as a biomarker of future cognition and, potentially, as a therapeutic target to improve cognition. They will need confirmation by further, more comprehensive studies also including unequivocal non-HRV sympathetic measures and meta-analyses.
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Affiliation(s)
- Paola Nicolini
- Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Geriatric Unit, Internal Medicine Department, 20122 Milan, Italy;
| | - Gabriella Malfatto
- Istituto Auxologico Italiano IRCCS, Department of Cardiovascular, Neural and Metabolic Sciences, Ospedale San Luca, 20149 Milan, Italy;
| | - Tiziano Lucchi
- Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Geriatric Unit, Internal Medicine Department, 20122 Milan, Italy;
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4
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Su Y, Wang F, Wang M, He S, Yang X, Luan Z. Effects of blood flow restriction training on muscle fitness and cardiovascular risk of obese college students. Front Physiol 2024; 14:1252052. [PMID: 38235388 PMCID: PMC10791898 DOI: 10.3389/fphys.2023.1252052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 12/12/2023] [Indexed: 01/19/2024] Open
Abstract
Purpose: The aim of this study was to investigate the effect of blood flow restriction (BFR) combined with low-intensity resistance training (RT) on cardiovascular risk factors in obese individuals. Methods: Twenty-six male obese college students were recruited and randomly assigned to a control group (CON, n = 8), a low-intensity RT group (RT, n = 9), and a combined BFR training and low-intensity RT group (BFRT, n = 9). Results: The subjects in BFRT group showed significant reductions in body fat percentage and waist-to-hip ratio and a significant increase in lean mass and muscle mass; the peak torque, peak power, and endurance ratio of knee extensors and elbow flexors were significantly upregulated; the root mean square (RMS) for the medial femoral muscle, lateral femoral muscle and biceps significantly increased; the diastolic blood pressure (DBP) showed a significant decrease. The BFRT group also showed significant up-regulations in RMS of the difference between the adjacent R-R intervals (RMSSD), high-frequency power (HF) of parasympathetic modulatory capacity, the standard deviation of R-R intervals (SDNN) of overall heart rate variability (HRV) changes and low-frequency power (LF) of predominantly sympathetic activity. In addition, glycated hemoglobin (HbA1C), insulin resistance index (HOMA-IR) and fasting blood glucose (FBG) were all significantly downregulated in BFRT group. In parallel, low-density lipoprotein (LDL-C) significantly reduced while high-density lipoprotein (HDL-C) significantly increased in BFRT group. Conclusion: BFR combined with low-intensity RT training effectively improved body composition index, increased muscle mass, improved neuromuscular activation, enhanced muscle strength and endurance, which in turn improved abnormal glucolipid metabolism and enhanced cardiac autonomic regulation.
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Affiliation(s)
- Yanhong Su
- Key Laboratory of Sports Human Science in Liaoning Province, College of Physical Education, Liaoning Normal University, Dalian, China
| | - Fuqing Wang
- Key Laboratory of Sports Human Science in Liaoning Province, College of Physical Education, Liaoning Normal University, Dalian, China
| | - Meng Wang
- Key Laboratory of Sports Human Science in Liaoning Province, College of Physical Education, Liaoning Normal University, Dalian, China
| | - Shiyong He
- Key Laboratory of Sports Human Science in Liaoning Province, College of Physical Education, Liaoning Normal University, Dalian, China
| | - Xiaolei Yang
- Key Laboratory of Sports Human Science in Liaoning Province, College of Physical Education, Liaoning Normal University, Dalian, China
| | - Zhilin Luan
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, China
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5
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Bizanti A, Zhang Y, Toledo Z, Bendowski KT, Harden SW, Mistareehi A, Chen J, Gozal D, Heal M, Christie R, Hunter PJ, Paton JFR, Cheng ZJ. Chronic intermittent hypoxia remodels catecholaminergic nerve innervation in mouse atria. J Physiol 2024; 602:49-71. [PMID: 38156943 PMCID: PMC10842556 DOI: 10.1113/jp284961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 10/04/2023] [Indexed: 01/03/2024] Open
Abstract
Chronic intermittent hypoxia (CIH, a model for sleep apnoea) is a major risk factor for several cardiovascular diseases. Autonomic imbalance (sympathetic overactivity and parasympathetic withdrawal) has emerged as a causal contributor of CIH-induced cardiovascular disease. Previously, we showed that CIH remodels the parasympathetic pathway. However, whether CIH induces remodelling of the cardiac sympathetic innervation remains unknown. Mice (male, C57BL/6J, 2-3 months) were exposed to either room air (RA, 21% O2 ) or CIH (alternating 21% and 5.7% O2 , every 6 min, 10 h day-1 ) for 8-10 weeks. Flat-mounts of their left and right atria were immunohistochemically labelled for tyrosine hydroxylase (TH, a sympathetic marker). Using a confocal microscope (or fluorescence microscope) and Neurlocudia 360 digitization and tracing system, we scanned both the left and right atria and quantitatively analysed the sympathetic axon density in both groups. The segmentation data was mapped onto a 3D mouse heart scaffold. Our findings indicated that CIH significantly remodelled the TH immunoreactive (-IR) innervation of the atria by increasing its density at the sinoatrial node, the auricles and the major veins attached to the atria (P < 0.05, n = 7). Additionally, CIH increased the branching points of TH-IR axons and decreased the distance between varicosities. Abnormal patterns of TH-IR axons around intrinsic cardiac ganglia were also found following CIH. We postulate that the increased sympathetic innervation may further amplify the effects of enhanced CIH-induced central sympathetic drive to the heart. Our work provides an anatomical foundation for the understanding of CIH-induced autonomic imbalance. KEY POINTS: Chronic intermittent hypoxia (CIH, a model for sleep apnoea) causes sympathetic overactivity, cardiovascular remodelling and hypertension. We determined the effect of CIH on sympathetic innervation of the mouse atria. In vivo CIH for 8-10 weeks resulted in an aberrant axonal pattern around the principal neurons within intrinsic cardiac ganglia and an increase in the density, branching point, tortuosity of catecholaminergic axons and atrial wall thickness. Utilizing mapping tool available from NIH (SPARC) Program, the topographical distribution of the catecholaminergic innervation of the atria were integrated into a novel 3D heart scaffold for precise anatomical distribution and holistic quantitative comparison between normal and CIH mice. This work provides a unique neuroanatomical understanding of the pathophysiology of CIH-induced autonomic remodelling.
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Affiliation(s)
- Ariege Bizanti
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - Yuanyuan Zhang
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - Zulema Toledo
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - Kohlton T Bendowski
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - Scott W Harden
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - Anas Mistareehi
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - Jin Chen
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - David Gozal
- Joan C. Edwards School of medicine, Marshall University, Huntington, WV, USA
| | - Maci Heal
- MBF Bioscience, Williston, Vermont, USA
| | - Richard Christie
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Peter J Hunter
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Julian F R Paton
- Department Physiology, Manaaki Manawa-the Centre for Heart Research, University of Auckland, Auckland, New Zealand
| | - Zixi Jack Cheng
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
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6
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Shively CA, Frye BM, Negrey JD, Johnson CSC, Sutphen CL, Molina AJA, Yadav H, Snyder-Mackler N, Register TC. The interactive effects of psychosocial stress and diet composition on health in primates. Neurosci Biobehav Rev 2023; 152:105320. [PMID: 37453725 PMCID: PMC10424262 DOI: 10.1016/j.neubiorev.2023.105320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 07/07/2023] [Accepted: 07/12/2023] [Indexed: 07/18/2023]
Abstract
Social disadvantage and diet composition independently impact myriad dimensions of health. They are closely entwined, as social disadvantage often yields poor diet quality, and may interact to fuel differential health outcomes. This paper reviews effects of psychosocial stress and diet composition on health in nonhuman primates and their implications for aging and human health. We examined the effects of social subordination stress and Mediterranean versus Western diet on multiple systems. We report that psychosocial stress and Western diet have independent and additive adverse effects on hypothalamic-pituitary-adrenal and autonomic nervous system reactivity to psychological stressors, brain structure, and ovarian function. Compared to the Mediterranean diet, the Western diet resulted in accelerated aging, nonalcoholic fatty liver disease, insulin resistance, gut microbial changes associated with increased disease risk, neuroinflammation, neuroanatomical perturbations, anxiety, and social isolation. This comprehensive, multisystem investigation lays the foundation for future investigations of the mechanistic underpinnings of psychosocial stress and diet effects on health, and advances the promise of the Mediterranean diet as a therapeutic intervention on psychosocial stress.
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Affiliation(s)
- Carol A Shively
- Department of Pathology, Comparative Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, USA.
| | - Brett M Frye
- Department of Pathology, Comparative Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, USA; Department of Biology, Emory and Henry College, Emory, VA, USA
| | - Jacob D Negrey
- Department of Pathology, Comparative Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | | | - Courtney L Sutphen
- Department of Pathology, Comparative Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | | | - Hariom Yadav
- Center for Microbiome Research, Microbiomes Institute, University of South Florida, Tampa, FL, USA
| | - Noah Snyder-Mackler
- Center for Evolution and Medicine, Arizona State University, Tempe, AZ, USA; School of Life Sciences, Arizona State University, Tempe, AZ, USA; School for Human Evolution and Social Change, Arizona State University, Tempe, AZ, USA
| | - Thomas C Register
- Department of Pathology, Comparative Medicine, Wake Forest University School of Medicine, Winston-Salem, NC, USA
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7
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Colas C, Le Berre Y, Fanget M, Savall A, Killian M, Goujon I, Labeix P, Bayle M, Féasson L, Roche F, Hupin D. Physical Activity in Long COVID: A Comparative Study of Exercise Rehabilitation Benefits in Patients with Long COVID, Coronary Artery Disease and Fibromyalgia. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:6513. [PMID: 37569053 PMCID: PMC10418371 DOI: 10.3390/ijerph20156513] [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: 06/30/2023] [Revised: 07/24/2023] [Accepted: 08/01/2023] [Indexed: 08/13/2023]
Abstract
Exercise in long COVID is poorly studied. Nevertheless, exerciserehabilitation could improve cardiorespiratory, muscular and autonomic functions. We aimed to investigate improvement in physical and autonomic performances of long COVID patients (n = 38) after a 4-week exercise rehabilitation program (3 sessions/week) compared to two control groups composed of coronary artery disease (n = 38) and fibromyalgia patients (n = 38), two populations for whom exercise benefits are well known. Efficacy of exercise training was assessed by a cardiopulmonary exercise test, a handgrip force test, and a supine heart rate variability recording at rest before and after the rehabilitation program. Cardiorespiratory and muscular parameters were enhanced after exercise rehabilitation in the three groups (p < 0.001). No significant difference was observed for the autonomic variables. Through this comparative study with control groups, we confirm and reinforce the interest of caring for long COVID patients without post-exertional symptom exacerbation by exercise rehabilitation of both strength and endurance training, by personalizing the program to the patient and symptoms.
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Affiliation(s)
- Claire Colas
- Department of Clinical and Exercise Physiology, University Hospital Center of Saint-Etienne, 42000 Saint-Etienne, France
- INSERM, U1059, DVH Team, SAINBIOSE, Jean Monnet University, 42000 Saint-Etienne, France
| | - Yann Le Berre
- Department of Clinical and Exercise Physiology, University Hospital Center of Saint-Etienne, 42000 Saint-Etienne, France
- Jacques Lisfranc Medicine Faculty, Jean Monnet University, 42000 Saint-Etienne, France
| | - Marie Fanget
- Department of Clinical and Exercise Physiology, University Hospital Center of Saint-Etienne, 42000 Saint-Etienne, France
- INSERM, U1059, DVH Team, SAINBIOSE, Jean Monnet University, 42000 Saint-Etienne, France
| | - Angélique Savall
- INSERM, U1059, DVH Team, SAINBIOSE, Jean Monnet University, 42000 Saint-Etienne, France
- Department of Education and Research in General Practice, Jean Monnet University, 42000 Saint-Etienne, France
| | - Martin Killian
- Department of Internal Medicine, University Hospital Center of Saint-Etienne, 42000 Saint-Etienne, France
- CIRI-Centre International de Recherche en Infectiologie, Team GIMAP, Jean Monnet University, Claude Bernard Lyon 1 University, Inserm, U1111, CNRS, UMR530, 42000 Saint-Etienne, France
- CIC 1408 Inserm, University Hospital Centre of Saint-Etienne, 42000 Saint-Etienne, France
| | - Ivan Goujon
- Department of Clinical and Exercise Physiology, University Hospital Center of Saint-Etienne, 42000 Saint-Etienne, France
| | - Pierre Labeix
- Department of Clinical and Exercise Physiology, University Hospital Center of Saint-Etienne, 42000 Saint-Etienne, France
- INSERM, U1059, DVH Team, SAINBIOSE, Jean Monnet University, 42000 Saint-Etienne, France
| | - Manon Bayle
- Department of Clinical and Exercise Physiology, University Hospital Center of Saint-Etienne, 42000 Saint-Etienne, France
| | - Léonard Féasson
- Department of Clinical and Exercise Physiology, University Hospital Center of Saint-Etienne, 42000 Saint-Etienne, France
- Inter-University Laboratory of Human Movement Biology, EA 7424, Jean Monnet University, 42000 Saint-Etienne, France
| | - Frederic Roche
- Department of Clinical and Exercise Physiology, University Hospital Center of Saint-Etienne, 42000 Saint-Etienne, France
- INSERM, U1059, DVH Team, SAINBIOSE, Jean Monnet University, 42000 Saint-Etienne, France
| | - David Hupin
- Department of Clinical and Exercise Physiology, University Hospital Center of Saint-Etienne, 42000 Saint-Etienne, France
- INSERM, U1059, DVH Team, SAINBIOSE, Jean Monnet University, 42000 Saint-Etienne, France
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8
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Millet GY, Bertrand MF, Lapole T, Féasson L, Rozand V, Hupin D. Measuring objective fatigability and autonomic dysfunction in clinical populations: How and why? Front Sports Act Living 2023; 5:1140833. [PMID: 37065809 PMCID: PMC10101442 DOI: 10.3389/fspor.2023.1140833] [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: 01/09/2023] [Accepted: 03/13/2023] [Indexed: 04/18/2023] Open
Abstract
Fatigue is a major symptom in many diseases, often among the most common and severe ones and may last for an extremely long period. Chronic fatigue impacts quality of life, reduces the capacity to perform activities of daily living, and has socioeconomical consequences such as impairing return to work. Despite the high prevalence and deleterious consequences of fatigue, little is known about its etiology. Numerous causes have been proposed to explain chronic fatigue. They encompass psychosocial and behavioral aspects (e.g., sleep disorders) and biological (e.g., inflammation), hematological (e.g., anemia) as well as physiological origins. Among the potential causes of chronic fatigue is the role of altered acute fatigue resistance, i.e. an increased fatigability for a given exercise, that is related to physical deconditioning. For instance, we and others have recently evidenced that relationships between chronic fatigue and increased objective fatigability, defined as an abnormal deterioration of functional capacity (maximal force or power), provided objective fatigability is appropriately measured. Indeed, in most studies in the field of chronic diseases, objective fatigability is measured during single-joint, isometric exercises. While those studies are valuable from a fundamental science point of view, they do not allow to test the patients in ecological situations when the purpose is to search for a link with chronic fatigue. As a complementary measure to the evaluation of neuromuscular function (i.e., fatigability), studying the dysfunction of the autonomic nervous system (ANS) is also of great interest in the context of fatigue. The challenge of evaluating objective fatigability and ANS dysfunction appropriately (i.e.,. how?) will be discussed in the first part of the present article. New tools recently developed to measure objective fatigability and muscle function will be presented. In the second part of the paper, we will discuss the interest of measuring objective fatigability and ANS (i.e. why?). Despite the beneficial effects of physical activity in attenuating chronic fatigue have been demonstrated, a better evaluation of fatigue etiology will allow to personalize the training intervention. We believe this is key in order to account for the complex, multifactorial nature of chronic fatigue.
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Affiliation(s)
- Guillaume Y. Millet
- Université Jean Monnet Saint-Etienne, Université Savoie Mont-Blanc, Inter-university Laboratory of Human Movement Biology, F-42023, Saint-Etienne, Lyon, France
- Institut Universitaire de France (IUF), Paris, France
- Correspondence: Guillaume Y. Millet
| | - Mathilde F. Bertrand
- Université Jean Monnet Saint-Etienne, Université Savoie Mont-Blanc, Inter-university Laboratory of Human Movement Biology, F-42023, Saint-Etienne, Lyon, France
| | - Thomas Lapole
- Université Jean Monnet Saint-Etienne, Université Savoie Mont-Blanc, Inter-university Laboratory of Human Movement Biology, F-42023, Saint-Etienne, Lyon, France
| | - Léonard Féasson
- Université Jean Monnet Saint-Etienne, Université Savoie Mont-Blanc, Inter-university Laboratory of Human Movement Biology, F-42023, Saint-Etienne, Lyon, France
- Service de physiologie clinique et de l'exercice, CHU de Saint-Étienne, Saint-Étienne, France
- Centre Référent Maladies Neuromusculaires rares - Euro-NmD, CHU de Saint-Étienne, Saint-Étienne, France
| | - Vianney Rozand
- Université Jean Monnet Saint-Etienne, Université Savoie Mont-Blanc, Inter-university Laboratory of Human Movement Biology, F-42023, Saint-Etienne, Lyon, France
| | - David Hupin
- Service de physiologie clinique et de l'exercice, CHU de Saint-Étienne, Saint-Étienne, France
- Jean Monnet University Saint-Etienne, Mines Saint-Etienne, University hospital of Saint-Etienne, INSERM, SAINBIOSE, U1059, DVH team, Saint-Etienne, France
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