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Kiperman T, Ma K. Circadian Clock in Muscle Disease Etiology and Therapeutic Potential for Duchenne Muscular Dystrophy. Int J Mol Sci 2024; 25:4767. [PMID: 38731986 PMCID: PMC11083552 DOI: 10.3390/ijms25094767] [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: 03/07/2024] [Revised: 04/20/2024] [Accepted: 04/25/2024] [Indexed: 05/13/2024] Open
Abstract
Circadian clock and clock-controlled output pathways exert temporal control in diverse aspects of skeletal muscle physiology, including the maintenance of muscle mass, structure, function, and metabolism. They have emerged as significant players in understanding muscle disease etiology and potential therapeutic avenues, particularly in Duchenne muscular dystrophy (DMD). This review examines the intricate interplay between circadian rhythms and muscle physiology, highlighting how disruptions of circadian regulation may contribute to muscle pathophysiology and the specific mechanisms linking circadian clock dysregulation with DMD. Moreover, we discuss recent advancements in chronobiological research that have shed light on the circadian control of muscle function and its relevance to DMD. Understanding clock output pathways involved in muscle mass and function offers novel insights into the pathogenesis of DMD and unveils promising avenues for therapeutic interventions. We further explore potential chronotherapeutic strategies targeting the circadian clock to ameliorate muscle degeneration which may inform drug development efforts for muscular dystrophy.
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Affiliation(s)
| | - Ke Ma
- Department of Diabetes Complications & Metabolism, Arthur Riggs Diabetes & Metabolism Research Institute, Beckman Research Institute of City of Hope, Duarte, CA 91010, USA;
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2
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Benchetrit S, Badariotti JI, Corbett J, Costello JT. The effects of sleep deprivation and extreme exertion on cognitive performance at the world-record breaking Suffolk Back Yard Ultra-marathon. PLoS One 2024; 19:e0299475. [PMID: 38483945 PMCID: PMC10939274 DOI: 10.1371/journal.pone.0299475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 02/09/2024] [Indexed: 03/17/2024] Open
Abstract
Using a prospective observational design, this study investigated the hypothesis that competing in the Suffolk Back Yard Ultra-marathon, would result in impaired cognitive performance and examined whether pre-race sleep patterns could mitigate this. Fifteen runners (1 female) volunteered to undertake this study and eleven males were included in the final analysis. Before the race and after withdrawal participants completed the following cognitive performance tasks: 2 Choice Reaction Time (2CRT), Stroop, and the Tower Puzzle. Pre-race sleep strategies were subjectively recorded with a 7-day sleep diary. Following race withdrawal, reaction time increased (Δ 77±68 ms; p = 0.004) in the 2CRT and executive function was impaired in the Stroop task (Interference score Δ -4.3±5.6 a.u.; p = 0.028). Decision making was not affected in the Tower Puzzle task. There was a significant correlation between the pre-race 7-day average sleep scores and both 2CRT Δ throughput (r = 0.61; p = 0.045) and 2CRT Δ RT (r = -0.64; p = 0.034). This study supports the hypothesis that running an ultra-marathon, which includes at least one night of sleep deprivation, impairs cognitive performance and provides novel evidence suggesting good sleep quality, in the week prior to an ultra-marathon, could minimise these effects.
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Affiliation(s)
- Sandy Benchetrit
- Extreme Environments Thematic Research Group, School of Sport, Health & Exercise Science, University of Portsmouth, Portsmouth, United Kingdom
- Gloucestershire Hospitals NHS Foundation Trust, Gloucestershire Royal Hospital, Gloucester, United Kingdom
| | - Juan I. Badariotti
- Extreme Environments Thematic Research Group, School of Sport, Health & Exercise Science, University of Portsmouth, Portsmouth, United Kingdom
| | - Jo Corbett
- Extreme Environments Thematic Research Group, School of Sport, Health & Exercise Science, University of Portsmouth, Portsmouth, United Kingdom
| | - Joseph T. Costello
- Extreme Environments Thematic Research Group, School of Sport, Health & Exercise Science, University of Portsmouth, Portsmouth, United Kingdom
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Marvin G, Schram B, Orr R, Canetti EFD. Occupation-Induced Fatigue and Impacts on Emergency First Responders: A Systematic Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:7055. [PMID: 37998287 PMCID: PMC10671419 DOI: 10.3390/ijerph20227055] [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: 09/04/2023] [Revised: 11/06/2023] [Accepted: 11/09/2023] [Indexed: 11/25/2023]
Abstract
Fatigue in emergency first responders (EFRs) is known to affect performance abilities and safety outcomes for both patients and EFRs. The primary aim of this review was to determine the main contributors to occupation-induced fatigue in EFRs and its subsequent impacts. Following the PRIMSA checklist, academic databases (Medline, Embase, CINAHL, and SPORTDiscus) were searched using key terms with results subjected to inclusion and exclusion criteria. Populations of interest were firefighters, paramedics, or emergency call centre personnel. Of the 5633 records identified, 43 studies, which reported on 186 unique measures from a total population of 6373 participants, informed the review. Synthesis revealed fatigue was caused by lack of sleep during the shift and consistent poor sleep quality which negatively impacted cognitive function, alertness, and physical and mental health while increasing safety-compromising behaviours and injuries. Both subjective and objective assessments of fatigue are necessary for effective risk management in EFRs. EFRs that are consistently fatigued are at a greater risk of poor physical and mental health, reduced cognitive function, and increased injuries. No studies reported on fatigue in emergency call centre personnel, highlighting a literature gap. Funding was provided by the Australian Capital Territory Emergency Services Agency. Preregistration was filed in OSF: osf.io/26f3s.
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Affiliation(s)
- Graham Marvin
- Tactical Research Unit, Faculty of Health Sciences & Medicine, Bond University, Robina, QLD 4226, Australia
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4
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Saddoud A, Rekik G, Belkhir Y, Kammoun N, Hidouri S, Chlif M, Jarraya M. One night of total sleep deprivation impairs decision-making skills, anaerobic performances, mood states, and perceptual responses in elite Kung-Fu athletes. BIOL RHYTHM RES 2022. [DOI: 10.1080/09291016.2022.2090673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Anis Saddoud
- High Institute of Sport and Physical Education of Sfax, University of Sfax, Sfax, Tunisia
- Research Laboratory: Education, Motricité, Sport Et Santé (EM2S, LR19JS01), High Institute of Sport and Physical Education of Sfax, University of Sfax, Sfax, Tunisia
| | - Ghazi Rekik
- Research Laboratory: Education, Motricité, Sport Et Santé (EM2S, LR19JS01), High Institute of Sport and Physical Education of Sfax, University of Sfax, Sfax, Tunisia
- Tanyu Research Laboratory, Taipei, Taiwan
| | - Yosra Belkhir
- Research Laboratory: Education, Motricité, Sport Et Santé (EM2S, LR19JS01), High Institute of Sport and Physical Education of Sfax, University of Sfax, Sfax, Tunisia
- High Institute of Sport and Physical Education of Ksar-Saïd, University of Manouba, Tunis, Tunisia
- Department of Physical Education, Al-Udhailiyah Primary School for Girls, Al-Farwaniyah, Kuwait
| | - Noureddine Kammoun
- High Institute of Sport and Physical Education of Sfax, University of Sfax, Sfax, Tunisia
| | - Sami Hidouri
- High Institute of Sport and Physical Education of Sfax, University of Sfax, Sfax, Tunisia
| | - Mehdi Chlif
- High Institute of Sport and Physical Education of Sfax, University of Sfax, Sfax, Tunisia
- Research Laboratory: Sports Performance Optimization, National Center of Medicine and Science in Sports (NCMSS), Tunis, Tunisia
- EA 3300 “APS and Motor Patterns: Adaptations-Rehabilitation”, Picardie Jules Verne University, Amiens, France
| | - Mohamed Jarraya
- High Institute of Sport and Physical Education of Sfax, University of Sfax, Sfax, Tunisia
- Research Laboratory: Education, Motricité, Sport Et Santé (EM2S, LR19JS01), High Institute of Sport and Physical Education of Sfax, University of Sfax, Sfax, Tunisia
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Douglas CM, Hesketh SJ, Esser KA. Time of Day and Muscle Strength: A Circadian Output? Physiology (Bethesda) 2021; 36:44-51. [PMID: 33325817 DOI: 10.1152/physiol.00030.2020] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
For more than 20 years, physiologists have observed a morning-to-evening increase in human muscle strength. Recent data suggest that time-of-day differences are the result of intrinsic, nonneural, muscle factors. We evaluate circadian clock data sets from human and mouse circadian studies and highlight possible mechanisms through which the muscle circadian clock may contribute to time-of-day muscle strength outcomes.
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Affiliation(s)
- Collin M Douglas
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, FloridaMyology Institute, University of Florida, Gainesville, Florida
| | - Stuart J Hesketh
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, FloridaMyology Institute, University of Florida, Gainesville, Florida
| | - Karyn A Esser
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, FloridaMyology Institute, University of Florida, Gainesville, Florida
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Can High Altitude Exacerbate a Remittent Alcohol Use Disorder in a Patient With a History of Panic Attacks? ADDICTIVE DISORDERS & THEIR TREATMENT 2020. [DOI: 10.1097/adt.0000000000000183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Moore BA, Brock MS, Brager A, Collen J, LoPresti M, Mysliwiec V. Posttraumatic Stress Disorder, Traumatic Brain Injury, Sleep, and Performance in Military Personnel. Sleep Med Clin 2020; 15:87-100. [DOI: 10.1016/j.jsmc.2019.11.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Graham SM, Martindale RJJ, McKinley M, Connaboy C, Andronikos G, Susmarski A. The examination of mental toughness, sleep, mood and injury rates in an Arctic ultra-marathon. Eur J Sport Sci 2020; 21:100-106. [PMID: 32089095 DOI: 10.1080/17461391.2020.1733670] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
There is scarcity of research examining the physiological and psychological effects of ultra-endurance racing on athletes in extreme conditions. The purpose of the current study was to identify common injury patterns and illness, profile mood states and sleep patterns and finally examine the relationships between mental toughness, sleep, mood and injury rates during a 120 mile, three-day Arctic ultra-marathon. Twelve participants (3 females, 9 males) with a mean age of 42 ± 5.35 yrs participated in the study. Mental toughness was measured using the MT18 questionnaire. Injuries were clinically assessed and recorded each day. Temperatures ranged from -20 to -6 degrees Celsius throughout the race. Sleep quantity and mood state were recorded using the BRUMS questionnaire. 10 out of the 12 participants experienced injuries; almost half of the participants had injuries that carried over a number of days. Mean sleep duration over the three days was 4.07 h, with an average of 0.78 injuries per day. Significant changes in mood were recorded across the three days, specifically a reduction in vigour (p = .029) and increase in fatigue (p = .014). Neither sleep quantity nor mental toughness was correlated with injury rate. Interestingly, sleep quantity was not related to changes in mood, as previously shown in ultra-marathons. Mental toughness had a moderate negative correlation (p < 0.01) with depression (-.623), reduced anger (-.616), confusion (-.558), increased vigour (.497) and tension (-.420) during the race. Success in this type of event involves significant psychological and physiological preparation to minimize the effects of sleep deprivation and avoidance of injuries.
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Affiliation(s)
- Scott Murray Graham
- School of Applied Sciences, Edinburgh Napier University, Edinburgh, Scotland.,School of Medicine, University of St. Andrews, St Andrews, Scotland
| | | | - Mairi McKinley
- School of Medicine, University of St. Andrews, St Andrews, Scotland
| | - Chris Connaboy
- Neuromuscular Research Laboratory, Warrior Human Performance Research Center, Department of Sports Medicine and Nutrition, University of Pittsburgh, Pittsburgh, PA, USA
| | - Georgios Andronikos
- School of Applied Sciences, Edinburgh Napier University, Edinburgh, Scotland
| | - Adam Susmarski
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
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Cullen T, Thomas G, Wadley AJ, Myers T. The effects of a single night of complete and partial sleep deprivation on physical and cognitive performance: A Bayesian analysis. J Sports Sci 2019; 37:2726-2734. [PMID: 31608829 DOI: 10.1080/02640414.2019.1662539] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
This study investigated the effects of complete and partial sleep deprivation on multiple aspects of athletic performance. Ten males completed a cognitive function test, maximal handgrip strength, countermovement jump (CMJ) and a 15 min all out cycling test to assess aerobic performance. These tests were performed following 3 different sleep conditions; normal sleep (CON), a 4 hr sleep opportunity (PART) and complete sleep deprivation (DEP). Data were analysed using a Bayesian multi-level regression model to provide probabilities of impairment (p = %). Aerobic performance, CMJ and handgrip strength were impaired by 11.4% (p = 100%), 10.9% (p = 100%) and 6% (p = 97%) following DEP, while aerobic performance and CMJ were highly likely impaired by 4.1% (p = 90%) and 5.2% (p = 94%) following PART. Cognitive reaction time was not impacted by PART or DEP. In contrast the accuracy of responses was highly likely impaired by 2% (91) following DEP, while there was less certainty of impaired accuracy following PART (-1%, p = 73). Multiple aspects of physical and cognitive performance were impacted by sleep deprivation. The greatest detrimental effects were seen for aerobic performance and CMJ. Partial sleep deprivation equating to 4 hrs of sleep causes subtle, but potentially important negative impairments on athletic performance.
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Affiliation(s)
- Tom Cullen
- Centre for Sport Exercise and Life Sciences, Coventry University, Coventry, UK
- School of Sport & Exercise Science, University of Worcester, Worcester, UK
| | - Gavin Thomas
- School of Sport & Exercise Science, University of Worcester, Worcester, UK
| | - Alex J. Wadley
- National Centre for Sport and Exercise Medicine, School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
- University Hospitals of Leicester NHS Trust, Leicester, UK
| | - Tony Myers
- Sport, Physical Activity and Health Research Centre, Newman University, Birmingham, UK
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Grandou C, Wallace L, Fullagar HHK, Duffield R, Burley S. The Effects of Sleep Loss on Military Physical Performance. Sports Med 2019; 49:1159-1172. [DOI: 10.1007/s40279-019-01123-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Effects of High vs. Low Glycemic Index of Post-Exercise Meals on Sleep and Exercise Performance: A Randomized, Double-Blind, Counterbalanced Polysomnographic Study. Nutrients 2018; 10:nu10111795. [PMID: 30453682 PMCID: PMC6267571 DOI: 10.3390/nu10111795] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Revised: 10/29/2018] [Accepted: 11/14/2018] [Indexed: 02/02/2023] Open
Abstract
The aim of the current study was to investigate the effect of the glycemic index of post-exercise meals on sleep quality and quantity, and assess whether those changes could affect the next day’s exercise performance. Following a baseline/familiarization phase, 10 recreationally trained male volunteers (23.2 ± 1.8 years) underwent two double-blinded, randomized, counterbalanced crossover trials. In both trials, participants performed sprint interval training (SIT) in the evening. Post-exercise, participants consumed a meal with a high (HGI) or low (LGI) glycemic index. Sleep parameters were assessed by a full night polysomnography (PSG). The following morning, exercise performance was evaluated by the countermovement jump (CMJ) test, a visual reaction time (VRT) test and a 5-km cycling time trial (TT). Total sleep time (TST) and sleep efficiency were greater in the HGI trial compared to the LGI trial (p < 0.05), while sleep onset latency was shortened by four-fold (p < 0.05) and VRT decreased by 8.9% (p < 0.05) in the HGI trial compared to the LGI trial. The performance in both 5-km TT and CMJ did not differ between trials. A moderate to strong correlation was found between the difference in TST and the VRT between the two trials (p < 0.05). In conclusion, this is the first study to show that a high glycemic index meal, following a single spring interval training session, can improve both sleep duration and sleep efficiency, while reducing in parallel sleep onset latency. Those improvements in sleep did not affect jumping ability and aerobic endurance performance. In contrast, the visual reaction time performance increased proportionally to sleep improvements.
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Keramidas ME, Gadefors M, Nilsson LO, Eiken O. Physiological and psychological determinants of whole-body endurance exercise following short-term sustained operations with partial sleep deprivation. Eur J Appl Physiol 2018; 118:1373-1384. [PMID: 29687266 PMCID: PMC6028900 DOI: 10.1007/s00421-018-3869-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 04/16/2018] [Indexed: 11/26/2022]
Abstract
Purpose The study examined the effects of short-term field-based military training with partial sleep deprivation on whole-body endurance performance in well-trained individuals. Methods Before and after a 2-day sustained operations (SUSOPS), 14 cadets performed a 15-min constant-load cycling at 65% of peak power output (PPO; CLT65), followed by an exhaustive constant-load trial at 85% of PPO (CLT85). Physiological [oxygen uptake (\documentclass[12pt]{minimal}
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\begin{document}$$\dot {V}$$\end{document}V˙O2), heart rate (HR), mean arterial pressure (MAP), cardiac output (CO), and regional oxygenation (TOI) in the frontal cerebral cortex and vastus lateralis muscle] and psychological [effort perception (RPE), affective valence (FS), and perceived activation (FAS)] variables were monitored during exercise. Results SUSOPS reduced time to exhaustion in CLT85 by 29.1% (p = 0.01). During the CLT65 trial, SUSOPS potentiated the exercise-induced elevations in \documentclass[12pt]{minimal}
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\begin{document}$$\dot {V}$$\end{document}V˙O2 and HR (p < 0.05), and blunted MAP (p = 0.001). CO did not differ between trials. Yet, towards the end of both CLT85 trials, CO tended to decline (p ≤ 0.08); a response that occurred at an earlier stage in the SUSOPS trial. During CLT65, SUSOPS altered neither cerebral nor muscle TOI. The SUSOPS CLT85 trial, however, was terminated at similar leg-muscle deoxygenation (p > 0.05) and lower prefrontal cortex deoxygenation (p < 0.01). SUSOPS increased RPE at submaximal intensities (p = 0.05), and suppressed FAS and FS throughout (p < 0.01). Conclusions The present findings indicate, therefore, that a brief period of military sustained operations with partial sleep deprivation augment cardiorespiratory and psychological strain, limiting high-intensity endurance capacity.
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Affiliation(s)
- Michail E Keramidas
- Department of Environmental Physiology, Swedish Aerospace Physiology Center, Royal Institute of Technology-KTH, Berzelius väg 13, 171 65, Solna, Sweden.
| | | | | | - Ola Eiken
- Department of Environmental Physiology, Swedish Aerospace Physiology Center, Royal Institute of Technology-KTH, Berzelius väg 13, 171 65, Solna, Sweden
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Martínez-Navarro I, Chiva-Bartoll O, Hernando B, Collado E, Porcar V, Hernando C. Hydration Status, Executive Function, and Response to Orthostatism After a 118-km Mountain Race: Are They Interrelated? J Strength Cond Res 2018; 32:441-449. [DOI: 10.1519/jsc.0000000000001614] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Fowler PM, Paul DJ, Tomazoli G, Farooq A, Akenhead R, Taylor L. Evidence of sub-optimal sleep in adolescent Middle Eastern academy soccer players which is exacerbated by sleep intermission proximal to dawn. Eur J Sport Sci 2017. [DOI: 10.1080/17461391.2017.1341553] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Peter M. Fowler
- ASPETAR – Orthopaedic and Sports Medicine Hospital, Athlete Health and Performance Research Centre, Doha, Qatar
| | - Darren J. Paul
- Football Excellence Project, ASPETAR – Orthopaedic and Sports Medicine Hospital, Doha, Qatar
| | - Gustavo Tomazoli
- Football Excellence Project, ASPETAR – Orthopaedic and Sports Medicine Hospital, Doha, Qatar
| | - Abdulaziz Farooq
- ASPETAR – Orthopaedic and Sports Medicine Hospital, Athlete Health and Performance Research Centre, Doha, Qatar
| | - Richard Akenhead
- Football Excellence Project, ASPETAR – Orthopaedic and Sports Medicine Hospital, Doha, Qatar
| | - Lee Taylor
- ASPETAR – Orthopaedic and Sports Medicine Hospital, Athlete Health and Performance Research Centre, Doha, Qatar
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
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Lucas SJE, Helge JW, Schütz UHW, Goldman RF, Cotter JD. Moving in extreme environments: extreme loading; carriage versus distance. EXTREME PHYSIOLOGY & MEDICINE 2016; 5:6. [PMID: 27110357 PMCID: PMC4840901 DOI: 10.1186/s13728-016-0047-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/02/2016] [Accepted: 04/01/2016] [Indexed: 12/17/2022]
Abstract
This review addresses human capacity for movement in the context of extreme loading and with it the combined effects of metabolic, biomechanical and gravitational stress on the human body. This topic encompasses extreme duration, as occurs in ultra-endurance competitions (e.g. adventure racing and transcontinental races) and expeditions (e.g. polar crossings), to the more gravitationally limited load carriage (e.g. in the military context). Juxtaposed to these circumstances is the extreme metabolic and mechanical unloading associated with space travel, prolonged bedrest and sedentary lifestyle, which may be at least as problematic, and are therefore included as a reference, e.g. when considering exposure, dangers and (mal)adaptations. As per the other reviews in this series, we describe the nature of the stress and the associated consequences; illustrate relevant regulations, including why and how they are set; present the pros and cons for self versus prescribed acute and chronic exposure; describe humans' (mal)adaptations; and finally suggest future directions for practice and research. In summary, we describe adaptation patterns that are often U or J shaped and that over time minimal or no load carriage decreases the global load carrying capacity and eventually leads to severe adverse effects and manifest disease under minimal absolute but high relative loads. We advocate that further understanding of load carrying capacity and the inherent mechanisms leading to adverse effects may advantageously be studied in this perspective. With improved access to insightful and portable technologies, there are some exciting possibilities to explore these questions in this context.
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Affiliation(s)
- Samuel J. E. Lucas
- />School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT UK
- />Department of Physiology, University of Otago, Dunedin, New Zealand
| | - Jørn W. Helge
- />Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Uwe H. W. Schütz
- />Department of Diagnostic and Interventional Radiology, University Hospital of Ulm, Ulm, Germany
- />Orthopaedic Consulting Office at the Green Tower and Medical Pain Centre Lake Constance–Upper Swabia, Ravensburg, Germany
| | | | - James D. Cotter
- />School of Physical Education, Sport and Exercise Sciences, University of Otago, Dunedin, New Zealand
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Tonacci A, Billeci L, Tartarisco G, Mastorci F, Borghini A, Mrakic-Sposta S, Moretti S, Vezzoli A, Faraguna U, Pioggia G, Guido G, Pratali L. A Novel Application for Cognitive Evaluation in Mountain Ultramarathons: Olfactory Assessment. Wilderness Environ Med 2016; 27:131-5. [PMID: 26948560 DOI: 10.1016/j.wem.2015.11.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 11/26/2015] [Accepted: 11/30/2015] [Indexed: 10/22/2022]
Abstract
OBJECTIVE Olfactory function, a cognitive impairment biomarker, was evaluated in mountain ultramarathon (MUM) runners during the Tor des Géants race (332.5 km with an overall altitude gain of 24,000 m; altitude range 330-3296 m above the sea). METHODS An Odor Identification Test was administered before (T0; n = 53), at 148.7 kms (T1; n = 32) and after the race (T2; n = 28). The effect of dehydration and sleep deprivation on olfactory function was assessed. Olfactory function was also assessed in non-MUM athletes and sedentary controls (C) at rest. RESULTS A majority of the athletes completed the olfactory test at all time intervals. Olfactory function decreased throughout the race (T0: 13.8 ± 1.9, T1: 13.7 ± 1.6, T2: 13.1 ± 1.8; T0 vs T2 P = .01). There was no relationship with race time or sleep deprivation on the sense of smell throughout the competition. However, there was a combined effect with decreased olfaction during the second half of the race, while a poor relationship was seen between olfaction and total body water at midterm (T1: rs = -0.427; P = .019), but not at baseline or after the race. MUM athletes had similar olfactory scores to C (13.8 ± 1.9 vs 13.7 ± 1.4) and non-MUM (13.8 ± 1.9 vs 13.9 ± 1.6) athletes. CONCLUSIONS This pilot study showed the feasibility of olfactory evaluation as a minimally invasive cognitive impairment assessment. The test can be used in logistically difficult environments, adding scientific value to this promising method. Although olfaction decreased after prolonged physical activity, further studies are warranted to make the relationship between cognition and external factors (eg, sleep deprivation, dehydration) more clear.
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Affiliation(s)
- Alessandro Tonacci
- Institute of Clinical Physiology, National Research Council of Italy (IFC-CNR), Pisa, Italy (Drs Tonacci, Billeci, Mastorci, and Pratali; and Mr Borghini).
| | - Lucia Billeci
- Institute of Clinical Physiology, National Research Council of Italy (IFC-CNR), Pisa, Italy (Drs Tonacci, Billeci, Mastorci, and Pratali; and Mr Borghini)
| | - Gennaro Tartarisco
- Institute of Clinical Physiology, National Research Council of Italy (IFC-CNR), Messina Unit, Messina, Italy (Drs Tartarisco and Pioggia)
| | - Francesca Mastorci
- Institute of Clinical Physiology, National Research Council of Italy (IFC-CNR), Pisa, Italy (Drs Tonacci, Billeci, Mastorci, and Pratali; and Mr Borghini)
| | - Andrea Borghini
- Institute of Bioimaging and Molecular Physiology, National Research Council of Italy, Segrate (MI), Italy (Drs Mrakic-Sposta, Moretti, and Vezzoli)
| | - Simona Mrakic-Sposta
- Institute of Bioimaging and Molecular Physiology, National Research Council of Italy, Segrate (MI), Italy (Drs Mrakic-Sposta, Moretti, and Vezzoli)
| | - Sarah Moretti
- Institute of Bioimaging and Molecular Physiology, National Research Council of Italy, Segrate (MI), Italy (Drs Mrakic-Sposta, Moretti, and Vezzoli)
| | - Alessandra Vezzoli
- Institute of Bioimaging and Molecular Physiology, National Research Council of Italy, Segrate (MI), Italy (Drs Mrakic-Sposta, Moretti, and Vezzoli)
| | - Ugo Faraguna
- Department of Translational Research on New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy (Dr Faraguna); IRCCS Stella Maris Scientific Institute, Calambrone, Pisa, Italy (Dr Faraguna)
| | - Giovanni Pioggia
- Institute of Clinical Physiology, National Research Council of Italy (IFC-CNR), Messina Unit, Messina, Italy (Drs Tartarisco and Pioggia)
| | - Giardini Guido
- Neurology and Neurophysiology Dept. Mountain Medicine Center Valle d'Aosta Regional Hospital, Aosta, Italy (Dr Giardini)
| | - Lorenza Pratali
- Institute of Clinical Physiology, National Research Council of Italy (IFC-CNR), Pisa, Italy (Drs Tonacci, Billeci, Mastorci, and Pratali; and Mr Borghini)
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17
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Sleepiness, attention and risk of accidents in powered two-wheelers. Sleep Med Rev 2016; 25:40-51. [DOI: 10.1016/j.smrv.2015.01.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 01/20/2015] [Accepted: 01/21/2015] [Indexed: 11/18/2022]
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18
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Ghayour Najafabadi M, Rahbar Nikoukar L, Memari A, Ekhtiari H, Beygi S. Does Ramadan Fasting Adversely Affect Cognitive Function in Young Females? SCIENTIFICA 2015; 2015:432428. [PMID: 26697263 PMCID: PMC4677254 DOI: 10.1155/2015/432428] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 11/15/2015] [Accepted: 11/16/2015] [Indexed: 06/05/2023]
Abstract
We examined the effects of Ramadan fasting on cognitive function in 17 female athletes. Data were obtained from participants of two fasting (n = 9) and nonfasting (n = 8) groups at three periods of the study (before Ramadan, at the third week in Ramadan, and after Ramadan). Digit span test (DST) and Stroop color test were employed to assess short-term memory and inhibition/cognitive flexibility at each time point. There were no significant changes for DST and Stroop task 1 in both groups, whereas Stroop task 2 and task 3 showed significant improvements in Ramadan condition (p < 0.05). Interference indices did not change significantly across the study except in post-Ramadan period of fasting group (p < 0.05). Group × week interaction was significant only for error numbers (p < 0.05). Athletes in nonfasting showed a significant decrease in number of errors in Ramadan compared to baseline (p < 0.05). The results suggest that Ramadan fasting may not adversely affect cognitive function in female athletes.
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Affiliation(s)
- Mahboubeh Ghayour Najafabadi
- Neuroscience Institute, Sports Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
- Faculty of Sports Sciences and Physical Education, University of Tehran, Tehran, Iran
| | - Laya Rahbar Nikoukar
- Neuroscience Institute, Sports Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Amir Memari
- Neuroscience Institute, Sports Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Hamed Ekhtiari
- Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Tehran, Iran
- Translational Neuroscience Program, Institute for Cognitive Science Studies, Tehran, Iran
| | - Sara Beygi
- Neuroscience Institute, Sports Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
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19
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Fullagar HHK, Skorski S, Duffield R, Hammes D, Coutts AJ, Meyer T. Sleep and athletic performance: the effects of sleep loss on exercise performance, and physiological and cognitive responses to exercise. Sports Med 2015; 45:161-86. [PMID: 25315456 DOI: 10.1007/s40279-014-0260-0] [Citation(s) in RCA: 410] [Impact Index Per Article: 45.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Although its true function remains unclear, sleep is considered critical to human physiological and cognitive function. Equally, since sleep loss is a common occurrence prior to competition in athletes, this could significantly impact upon their athletic performance. Much of the previous research has reported that exercise performance is negatively affected following sleep loss; however, conflicting findings mean that the extent, influence, and mechanisms of sleep loss affecting exercise performance remain uncertain. For instance, research indicates some maximal physical efforts and gross motor performances can be maintained. In comparison, the few published studies investigating the effect of sleep loss on performance in athletes report a reduction in sport-specific performance. The effects of sleep loss on physiological responses to exercise also remain equivocal; however, it appears a reduction in sleep quality and quantity could result in an autonomic nervous system imbalance, simulating symptoms of the overtraining syndrome. Additionally, increases in pro-inflammatory cytokines following sleep loss could promote immune system dysfunction. Of further concern, numerous studies investigating the effects of sleep loss on cognitive function report slower and less accurate cognitive performance. Based on this context, this review aims to evaluate the importance and prevalence of sleep in athletes and summarises the effects of sleep loss (restriction and deprivation) on exercise performance, and physiological and cognitive responses to exercise. Given the equivocal understanding of sleep and athletic performance outcomes, further research and consideration is required to obtain a greater knowledge of the interaction between sleep and performance.
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Affiliation(s)
- Hugh H K Fullagar
- Institute of Sport and Preventive Medicine, Saarland University, GEB. B82, 66123, Saarbrucken, Germany,
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20
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Poussel M, Laroppe J, Hurdiel R, Girard J, Poletti L, Thil C, Didelot A, Chenuel B. Sleep Management Strategy and Performance in an Extreme Mountain Ultra-marathon. Res Sports Med 2015; 23:330-6. [PMID: 26020095 DOI: 10.1080/15438627.2015.1040916] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
We intended to assess the relationship between sleep strategies and performance during the North-Face Ultra-Trail du Mont-Blanc 2013, to test the hypothesis that sleep management can influence athletic performance. Almost all runners specifically adopted sleep management strategies before the race. Among the finishers 72% didn't sleep at all during the race and 28% took a least one break for sleep. Non-sleepers completed the race faster than the sleepers (P = 0.0008). Race time was positively correlated with drowsiness (P < 0.0001) and negatively correlated with the number participations in this race (P = 0.0039). Runners who adopted a sleep management strategy based on increased sleep time before the race completed the race faster (P = 0.0258). Most finishers seemed to be aware of the importance of developing sleep management strategies and increasing sleep time some nights before the race appeared to be the most relevant strategy to improve performance.
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Affiliation(s)
- Mathias Poussel
- a Department of Pulmonary Function Testing and Exercise Testing, CHU Nancy, Nancy, F-54000, France and EA 3450 DevAH - Development, Adaptation and Disadvantage, Cardiorespiratory regulations and motor control , Université de Lorraine , Nancy , F-54000 , France
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21
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Hurdiel R, Pezé T, Daugherty J, Girard J, Poussel M, Poletti L, Basset P, Theunynck D. Combined effects of sleep deprivation and strenuous exercise on cognitive performances during The North Face® Ultra Trail du Mont Blanc® (UTMB®). J Sports Sci 2014; 33:670-4. [PMID: 25333827 DOI: 10.1080/02640414.2014.960883] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
This study investigated the effects of combined sleep deprivation and strenuous exercise on cognitive and neurobehavioral performance among long-distance runners completing one of the most difficult ultramarathons in the world. Seventeen runners participated. Each had a wrist-worn actigraph throughout the race to record their sleep time. In addition, each individual's performance in 10-min response-time tests before and after the race was recorded and a questionnaire enabled participants to report any difficulties they experienced during the competition. During race completion times of 27 to 44 h, combined acute lack of sleep (12 ± 17 min of rest during the race) and strenuous exercise (168.0 km) had marked adverse effects on cognitive performances ranging from mere lengthening of response time to serious symptoms such as visual hallucinations. This study suggests that regardless of rest duration and time in race, cognitive performances of ultramarathoners are adversely affected.
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Affiliation(s)
- Rémy Hurdiel
- a Laboratoire URePSSS-ReLACS , Université du Littoral Côte d'Opale , Dunkerque , France
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22
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Prolonged sleep deprivation and continuous exercise: effects on melatonin, tympanic temperature, and cognitive function. BIOMED RESEARCH INTERNATIONAL 2014; 2014:781863. [PMID: 25110695 PMCID: PMC4109589 DOI: 10.1155/2014/781863] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 06/10/2014] [Accepted: 06/15/2014] [Indexed: 11/18/2022]
Abstract
The purpose of this study was to examine tympanic temperature, melatonin, and cognitive function during a 36-hour endurance event. Nine male and three female participants took part in a 36-hour sustained endurance event without sleep (N = 12, mean age = 31.8 ± 5.0 yrs). Participants were stopped for data collection at checkpoints throughout the 36-hour event. Tympanic temperature was assessed, a psychomotor vigilance test (PVT) was administered, and saliva samples were collected. Salivary melatonin was determined via immunoassay. During the 36 hours of competition, melatonin levels were negatively correlated with the day of the race (rs = −0.277, P = 0.039) and positively associated with nighttime (rs = 0.316, P = 0.021). Significant main effects of tympanic temperature (P < 0.001), day of the competition (P = 0.018), and a tympanic temperature ∗ day of competition interaction (P < 0.001) were used to predict minor lapses in attention. No associations between melatonin levels and cognitive function were observed (P > 0.05). During the event tympanic temperature declined and was associated with an increase in lapses in attention. With sustained endurance events becoming more popular future research is warranted to evaluate the physiological impact of participation.
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23
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Sleep and exercise: a reciprocal issue? Sleep Med Rev 2014; 20:59-72. [PMID: 25127157 DOI: 10.1016/j.smrv.2014.06.008] [Citation(s) in RCA: 374] [Impact Index Per Article: 37.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 06/17/2014] [Accepted: 06/20/2014] [Indexed: 12/18/2022]
Abstract
Sleep and exercise influence each other through complex, bilateral interactions that involve multiple physiological and psychological pathways. Physical activity is usually considered as beneficial in aiding sleep although this link may be subject to multiple moderating factors such as sex, age, fitness level, sleep quality and the characteristics of the exercise (intensity, duration, time of day, environment). It is therefore vital to improve knowledge in fundamental physiology in order to understand the benefits of exercise on the quantity and quality of sleep in healthy subjects and patients. Conversely, sleep disturbances could also impair a person's cognitive performance or their capacity for exercise and increase the risk of exercise-induced injuries either during extreme and/or prolonged exercise or during team sports. This review aims to describe the reciprocal fundamental physiological effects linking sleep and exercise in order to improve the pertinent use of exercise in sleep medicine and prevent sleep disorders in sportsmen.
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24
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Breslin G, Murphy MH, Kremer J, McClean C, Davison G. Providing Sport Psychology Support to an Athlete in a Unique, Ultra-Endurance Event. JOURNAL OF SPORT PSYCHOLOGY IN ACTION 2014. [DOI: 10.1080/21520704.2014.892911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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25
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McLellan TM. Protein supplementation for military personnel: a review of the mechanisms and performance outcomes. J Nutr 2013; 143:1820S-1833S. [PMID: 24027180 DOI: 10.3945/jn.113.176313] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Protein supplement use is common among athletes, active adults, and military personnel. This review provides a summary of the evidence base that either supports or refutes the ergogenic effects associated with different mechanisms that have been proposed to support protein supplementation. It was clear that if carbohydrate delivery was optimal either during or after an acute bout of exercise that additional protein will not increase exercise capacity. Evidence was also weak to substantiate use of protein supplements to slow the increase in brain serotonin and onset of central fatigue. It was also evident that additional research is warranted to test whether the benefits of protein supplements for enhancing recovery of fluid balance after exercise will affect subsequent work in the heat. In contrast, with repeated exercise, use of protein supplementation was associated with reductions in muscle soreness and often a faster recovery of muscle function due to reductions in protein degradation. There was also good supportive evidence for long-term benefits of protein supplementation for gains in muscle mass and strength through accelerated rates of protein synthesis, as long as the training stimulus was of sufficient intensity, frequency, and duration. However, studies have not examined the impact of protein supplements under the combined stress of a military environment that includes repeated bouts of exercise with little opportunity for feeding and recovery, lack of sleep, and exposure to extreme environments. Both additional laboratory and field research is warranted to help provide evidence-based guidance for the choice of protein supplements to enhance soldier performance.
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26
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Morrison SA, Cheung SS, Hurst RD, Cotter JD. Cognitive function and blood-brain barrier permeability during exercise in the heat: Effect of fitness and bovine colostrum supplementation. J Therm Biol 2013. [DOI: 10.1016/j.jtherbio.2013.05.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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27
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Evans MB, Hoar SD, Gebotys RJ, Marchesin CA. Endurance athletes' coping function use during competitive suffering episodes. Eur J Sport Sci 2013; 14:368-75. [PMID: 24003768 DOI: 10.1080/17461391.2013.832803] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Endurance athletes who realise that they are falling short of important personal goals during competition are expected to experience competitive suffering. As a negative affective state with implications for performance and personal experiences, it is important to understand how endurance athletes cope with competitive suffering. Thus, the purpose of this study was to investigate differences in athletes' momentary coping function use over time during a competitive suffering episode. Twenty-six runners (mean age: 35.8 years) completed a 5-km running time trial that evoked an experience of competitive suffering using false failure-oriented feedback. Momentary assessments of goal attainment feelings and coping function use were completed immediately following the running time trial using video-mediated recall. Pooled time series analysis was used to predict coping function use across several points in time (i.e. earlier and later stages of a competitive suffering episode) and at different ratings of goal attainment feelings. Analyses revealed that negative feelings about goal attainment moderately predicted problem-focused coping use, and strongly predicted emotion-focused coping use. Although it was not predicted by goal attainment feelings, avoidance coping use was decreased over time throughout suffering episodes. Overall, this study supports propositions that the coping process is continually adapted to competitive demands and identifies the roles of distinct coping functions within the total coping effort.
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Affiliation(s)
- Michael Blair Evans
- a Department of Psychology , Wilfrid Laurier University , Waterloo , ON , Canada
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28
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Rüst CA, Knechtle B, Knechtle P, Lepers R, Rosemann T, Onywera V. European athletes dominate performances in Double Iron ultra-triathlons--a retrospective data analysis from 1985 to 2010. Eur J Sport Sci 2012; 14 Suppl 1:S39-50. [PMID: 24111900 DOI: 10.1080/17461391.2011.641033] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
We investigated the participation and performance trends of ultra-endurance triathletes from all nationalities competing in a Double Iron ultra-triathlon (7.6-km swim, 360-km cycle and 84.4-km run) from 1985 to 2010. A total of 1854 athletes participated in 92 Double Iron ultra-triathlons. The majority of the winners came from Europe with 72 victories, followed by North America with 17 victories. The race time for the European ultra-triathletes was 1340 (s=95.3) min, decreasing highly significantly (r (2)=0.28; P<0.0001) across the years. North American ultra-triathletes finished the races within 1556 (s=124.5) min; their race time showed no changes across the years (r (2)=0.045; P=0.07). The race time for the Europeans was highly significantly faster compared to the North Americans (P<0.0001). Future studies should investigate each country in Europe and North America in order to find the country with the largest participation of athletes and their best performance.
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Affiliation(s)
- Christoph Alexander Rüst
- a Institute of General Practice and for Health Services Research, University of Zurich , Zürich , Switzerland
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29
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Lucas SJE, Ainslie PN, Murrell CJ, Thomas KN, Franz EA, Cotter JD. Effect of age on exercise-induced alterations in cognitive executive function: relationship to cerebral perfusion. Exp Gerontol 2012; 47:541-51. [PMID: 22230488 DOI: 10.1016/j.exger.2011.12.002] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Revised: 12/06/2011] [Accepted: 12/12/2011] [Indexed: 11/29/2022]
Abstract
Regular exercise improves the age-related decline in cerebral blood flow (CBF) and is associated with improved cognitive function; however, less is known about the direct relationship between CBF and cognitive function. We examined the influence of healthy aging on the capability of acute exercise to improve cognition, and whether exercise-induced improvements in cognition are related to CBF and cortical hemodynamics. Middle cerebral artery blood flow velocity (MCAv; Doppler) and cortical hemodynamics (NIRS) were measured in 13 young (24±5 y) and 9 older (62±3 y) participants at rest and during cycling at 30% and 70% of heart rate range (HRR). Cognitive performance was assessed using a computer-adapted Stroop task (i.e., test of executive function cognition) at rest and during exercise. Average response times on the Stroop task were slower for the older compared to younger group for both simple and difficult tasks (P<0.01). Independent of age, difficult-task response times improved during exercise (P<0.01), with the improvement greater at 70% HRR exercise (P=0.04 vs. 30% HRR). Higher MCAv was correlated with faster response times for simple and difficult tasks at rest (R(2)=0.47 and R(2)=0.47, respectively), but this relation uncoupled progressively during exercise. Exercise-induced increases in MCAv were similar and unaltered during cognitive tasks for both age groups. In contrast, prefrontal cortical hemodynamic NIRS measures [oxyhemoglobin (O(2)Hb) and total hemoglobin (tHb)] were differentially affected by exercise intensity, age and cognitive task; e.g., there were smaller increases in [O(2)Hb] and [tHb] in the older group between exercise intensities (P<0.05). These data indicate that: 1) Regardless of age, cognitive (executive) function is improved while exercising; 2) while MCAv is strongly related to cognition at rest, this relation becomes uncoupled during exercise, and 3) there is dissociation between global CBF and regional cortical oxygenation and NIRS blood volume markers during exercise and engagement of prefrontal cognition.
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Affiliation(s)
- Samuel J E Lucas
- Department of Physiology, University of Otago, Dunedin, New Zealand.
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30
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Murphy MH, Breslin G, Trinick T, McClean C, Moore W, Duly E, Davison GW. The biochemical, physiological and psychological consequences of a "1,000 miles in 1,000 hours" walking challenge. Eur J Appl Physiol 2011; 112:781-8. [PMID: 21603997 DOI: 10.1007/s00421-011-2003-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Accepted: 05/09/2011] [Indexed: 10/18/2022]
Abstract
The combined effects of 42 days of chronic sleep disruption and repeated hourly bouts of physical exertion have not been described. This case study reports the physiological and psychological demands placed on one individual who walked 1 mile in each consecutive hour for a period of 1,000 h (42 days), covering a total distance of 1,000 miles. The participant walked at a mean speed of 1.75 m/s completing each mile in approximately 15 min. Over the course of the challenge, the individual lost 1.6 kg in body weight. Markers of skeletal muscle damage, increased gradually whilst free testosterone levels decreased over the course of the challenge. Stress hormones increased whilst inflammatory markers (CRP) initially rose but then returned towards baseline over the course of the study. Cognitive motor performance measured via reaction time was maintained throughout the 42 days. The participant also displayed mood states typical of an elite athlete at baseline and throughout the challenge. Participation in this novel '1,000 mile 1,000 h' walking challenge evoked considerable physiological stress in a fit, healthy middle-aged participant but did not markedly alter cognitive performance or mood over the 42-day period.
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Affiliation(s)
- M H Murphy
- Sport and Exercise Sciences Research Institute, University of Ulster, Jordanstown, Belfast, BT37 OQB, UK.
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