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Elghobashy ME, Richards AJ, Malekzadeh R, Patel D, Turner LV, Burr JF, Power GA, Laham R, Riddell MC, Cheng AJ. Carbohydrate Ingestion Increases Interstitial Glucose and Mitigates Neuromuscular Fatigue during Single-Leg Knee Extensions. Med Sci Sports Exerc 2024; 56:1495-1504. [PMID: 38595179 DOI: 10.1249/mss.0000000000003440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
INTRODUCTION We aimed to investigate the neuromuscular contributions to enhanced fatigue resistance with carbohydrate (CHO) ingestion and to identify whether fatigue is associated with changes in interstitial glucose levels assessed using a continuous glucose monitor (CGM). METHODS Twelve healthy participants (six males, six females) performed isokinetic single-leg knee extensions (90°·s -1 ) at 20% of the maximal voluntary contraction (MVC) torque until MVC torque reached 60% of its initial value (i.e., task failure). Central and peripheral fatigue were evaluated every 15 min during the fatigue task using the interpolated twitch technique and electrically evoked torque. Using a single-blinded crossover design, participants ingested CHO (85 g sucrose per hour), or a placebo (PLA), at regular intervals during the fatigue task. Minute-by-minute interstitial glucose levels measured via CGM and whole blood glucose readings were obtained intermittently during the fatiguing task. RESULTS CHO ingestion increased time to task failure over PLA (113 ± 69 vs 81 ± 49 min, mean ± SD; P < 0.001) and was associated with higher glycemia as measured by CGM (106 ± 18 vs 88 ± 10 mg·dL -1 , P < 0.001) and whole blood glucose sampling (104 ± 17 vs 89 ± 10 mg·dL -1 , P < 0.001). When assessing the values in the CHO condition at a similar time point to those at task failure in the PLA condition (i.e., ~81 min), MVC torque, percentage voluntary activation, and 10 Hz torque were all better preserved in the CHO versus PLA condition ( P < 0.05). CONCLUSIONS Exogenous CHO intake mitigates neuromuscular fatigue at both the central and peripheral levels by raising glucose concentrations rather than by preventing hypoglycemia.
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Affiliation(s)
- Mohamed E Elghobashy
- Muscle Health Research Centre, School of Kinesiology and Health Science, Faculty of Health, York University, Toronto, Ontario, CANADA
| | - Andrew J Richards
- Muscle Health Research Centre, School of Kinesiology and Health Science, Faculty of Health, York University, Toronto, Ontario, CANADA
| | - Rohin Malekzadeh
- Muscle Health Research Centre, School of Kinesiology and Health Science, Faculty of Health, York University, Toronto, Ontario, CANADA
| | - Disha Patel
- Muscle Health Research Centre, School of Kinesiology and Health Science, Faculty of Health, York University, Toronto, Ontario, CANADA
| | - Lauren V Turner
- Muscle Health Research Centre, School of Kinesiology and Health Science, Faculty of Health, York University, Toronto, Ontario, CANADA
| | - Jamie F Burr
- Department of Human Health and Nutritional Sciences, College of Biological Sciences, University of Guelph, Guelph, Ontario, CANADA
| | - Geoffrey A Power
- Department of Human Health and Nutritional Sciences, College of Biological Sciences, University of Guelph, Guelph, Ontario, CANADA
| | - Robert Laham
- Muscle Health Research Centre, School of Kinesiology and Health Science, Faculty of Health, York University, Toronto, Ontario, CANADA
| | - Michael C Riddell
- Muscle Health Research Centre, School of Kinesiology and Health Science, Faculty of Health, York University, Toronto, Ontario, CANADA
| | - Arthur J Cheng
- Muscle Health Research Centre, School of Kinesiology and Health Science, Faculty of Health, York University, Toronto, Ontario, CANADA
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Oxfeldt M, Marsi D, Christensen PM, Andersen OE, Johansen FT, Bangshaab M, Risikesan J, Jeppesen JS, Hellsten Y, Phillips SM, Melin AK, Ørtenblad N, Hansen M. Low Energy Availability Followed by Optimal Energy Availability Does Not Benefit Performance in Trained Females. Med Sci Sports Exerc 2024; 56:902-916. [PMID: 38181220 DOI: 10.1249/mss.0000000000003370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2024]
Abstract
PURPOSE Short periods of reduced energy availability are commonly undertaken by athletes to decrease body mass, possibly improve the power-to-mass ratio, and enhance physical performance. Our primary aim was to investigate the impact of 10 d of low energy availability (LEA) followed by 2 d of optimal energy availability (OEA) on physical performance parameters in trained females. Second, physiological markers at the whole-body and molecular level related to performance were evaluated. METHODS Thirty young trained eumenorrheic females were matched in pairs based on training history and randomized to a 10-d intervention period of LEA (25 kcal·fat-free mass (FFM) -1 ·d -1 ) or OEA (50 kcal·FFM -1 ·d -1 ) along with supervised exercise training. Before the intervention, participants underwent a 5-d run-in period with OEA + supervised exercise training. After the LEA intervention, 2 d of recovery with OEA was completed. Participants underwent muscle biopsies, blood sampling, physical performance tests, body composition measurements, and resting metabolic rate measurements. A linear mixed model was used with group and time as fixed effects and subject as random effects. RESULTS Compared with OEA, LEA resulted in reduced body mass, muscle glycogen content, repeated sprint ability, 4-min time-trial performance, and rate of force development of the knee extensors (absolute values; P < 0.05). Two days of recovery restored 4-min time-trial performance and partly restored repeated sprint ability, but performance remained inferior to the OEA group. When the performance data were expressed relative to body mass, LEA did not enhance performance. CONCLUSIONS Ten days of LEA resulted in impaired performance (absolute values), with concomitant reductions in muscle glycogen. Two days of recovery with OEA partially restored these impairments, although physical performance (absolute values) was still inferior to being in OEA. Our findings do not support the thesis that LEA giving rise to small reductions in body mass improves the power-to-mass ratio and thus increases physical performance.
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Affiliation(s)
- Mikkel Oxfeldt
- Department of Public Health, Aarhus University, Aarhus C, DENMARK
| | - Daniel Marsi
- Department of Public Health, Aarhus University, Aarhus C, DENMARK
| | | | | | | | | | - Jeyanthini Risikesan
- Department of Child and Adolescent Medicine, Regional Hospital Gødstrup, Gødstrup, DENMARK
| | - Jan S Jeppesen
- Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, DENMARK
| | - Ylva Hellsten
- Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, DENMARK
| | - Stuart M Phillips
- Department of Kinesiology, McMaster University, Hamilton, Ontario, CANADA
| | - Anna K Melin
- Department of Sport Science, Linnaeus University, Växjö/Kalmar, SWEDEN
| | - Niels Ørtenblad
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense M, DENMARK
| | - Mette Hansen
- Department of Public Health, Aarhus University, Aarhus C, DENMARK
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Rollo I, Williams C. Carbohydrate Nutrition and Skill Performance in Soccer. Sports Med 2023; 53:7-14. [PMID: 37421586 PMCID: PMC10721660 DOI: 10.1007/s40279-023-01876-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/08/2023] [Indexed: 07/10/2023]
Abstract
In soccer, players must perform a variety of sport-specific skills usually during or immediately after running, often at sprint speed. The quality of the skill performed is likely influenced by the volume of work done in attacking and defending over the duration of the match. Even the most highly skilful players succumb to the impact of fatigue both physical and mental, which may result in underperforming skills at key moments in a match. Fitness is the platform on which skill is performed during team sport. With the onset of fatigue, tired players find it ever more difficult to successfully perform basic skills. Therefore, it is not surprising that teams spend a large proportion of their training time on fitness. While acknowledging the central role of fitness in team sport, the importance of team tactics, underpinned by spatial awareness, must not be neglected. It is well established that a high-carbohydrate diet before a match and, as a supplement during match play, helps delay the onset of fatigue. There is some evidence that players ingesting carbohydrate can maintain sport-relevant skills for the duration of exercise more successfully compared with when ingesting placebo or water. However, most of the assessments of sport-specific skills have been performed in a controlled, non-contested environment. Although these methods may be judged as not ecologically valid, they do rule out the confounding influences of competition on skill performance. The aim of this brief review is to explore whether carbohydrate ingestion, while delaying fatigue during match play, may also help retain sport soccer-specific skill performance.
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Affiliation(s)
- Ian Rollo
- Gatorade Sports Science Institute, PepsiCo Life Sciences, Global R&D, Leicestershire, UK.
- School of Sports Exercise and Health Sciences, Loughborough University, Loughborough, UK.
| | - Clyde Williams
- School of Sports Exercise and Health Sciences, Loughborough University, Loughborough, UK
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Ashton JS, Roberts JW, Wakefield CJ, MacLaren DPM, Marwood S, Malone JJ. Medium chain triglycerides with a C8:C10 ratio of 30:70 enhances cognitive performance and mitigates the cognitive decline associated with prolonged exercise in young and healthy adults. Physiol Behav 2023; 269:114284. [PMID: 37394051 DOI: 10.1016/j.physbeh.2023.114284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 06/09/2023] [Accepted: 06/27/2023] [Indexed: 07/04/2023]
Abstract
INTRODUCTION Prolonged exercise has been linked to a decline in cognitive function due to a variety of factors, such as a drop in oxygen in the prefrontal cortex and an increase in stress hormones and neurotransmitters. Medium chain triglycerides (MCTs) may possibly offset this decline as they provide energy for the brain via both direct and indirect pathways, alongside promoting chronic physiological adaptations within the brain. METHODS Participants were divided into two groups; MCT (n = 9) and Placebo (n = 10). The MCT gels contained 6 g of MCT with a C8:C10 ratio of 30:70, whereas the placebo gels contained carbohydrates of similar calorific value to the MCT gels. Participants visited the laboratory on three occasions (familiarisation/fitness test, pre-supplementation, post-supplementation), during which they performed a battery of cognitive tasks assessing domains such as processing speed, working memory, selective attention, decision making and coordination, before and after a prolonged bout of exercise (60 mins at 90% gas exchange threshold (GET). A 2-week supplementation period between visits 2 and 3 involved the ingestion of 2 gels per day. RESULTS Exercise resulted in detriments in most cognitive tasks pre-supplementation for both groups, and post-supplementation for the Placebo group (main effect ps< 0.05). Post-supplementation, the effect of exercise was mediated in the MCT group for all cognitive tasks (main effect ps< 0.05), except for the Digit and Spatial Span Backwards test phases (main effect ps> 0.05). Furthermore, MCT supplementation enhanced before-exercise cognitive performance and in some measures, such as working memory, this was maintained after-exercise (interaction effect ps> 0.05). CONCLUSIONS Chronic MCT supplementation enhanced before-exercise cognitive performance and offset the cognitive decline caused by a prolonged bout of exercise. In some cases, improvements in before-exercise cognitive performance were maintained after-exercise.
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Affiliation(s)
- Jake S Ashton
- School of Health and Sport Sciences, Liverpool Hope University, Liverpool, UK.
| | - James W Roberts
- School of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | | | - Don P M MacLaren
- School of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Simon Marwood
- School of Health and Sport Sciences, Liverpool Hope University, Liverpool, UK
| | - James J Malone
- School of Health and Sport Sciences, Liverpool Hope University, Liverpool, UK
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Karpęcka-Gałka E, Mazur-Kurach P, Szyguła Z, Frączek B. Diet, Supplementation and Nutritional Habits of Climbers in High Mountain Conditions. Nutrients 2023; 15:4219. [PMID: 37836503 PMCID: PMC10574574 DOI: 10.3390/nu15194219] [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: 09/07/2023] [Revised: 09/26/2023] [Accepted: 09/27/2023] [Indexed: 10/15/2023] Open
Abstract
Appropriate nutritional preparation for a high-mountain expedition can contribute to the prevention of nutritional deficiencies affecting the deterioration of health and performance. The aim of the study was to analyze the dietary habits, supplementation and nutritional value of diets of high mountain climbers. The study group consisted of 28 men (average age 33.12 ± 5.96 years), taking part in summer mountaineering expeditions at an altitude above 3000 m above sea level, lasting at least 3 weeks. Food groups consumed with low frequency during the expedition include vegetables, fruits, eggs, milk and milk products, butter and cream, fish and meat. The energy demand of the study participants was 4559.5 ± 425 kcal, and the energy supply was 2776.8 ± 878 kcal. The participants provided 79.6 ± 18.5 g of protein (1.1 ± 0.3 g protein/kg bw), 374.0 ± 164.5 g of carbohydrates (5.3 ± 2.5 g/kg bw) and 110.7 ± 31.7 g of fat (1.6 ± 0.5 g/kg bw) in the diet. The climbers' diet was low in calories, the protein supply was too low, and the fat supply was too high. There is a need to develop nutritional and supplementation recommendations that would serve as guidelines for climbers, improving their well-being and exercise capacity in severe high-mountain conditions, which would take their individual taste preferences into account.
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Affiliation(s)
- Ewa Karpęcka-Gałka
- Doctoral School of Physical Culture Sciences, University School of Physical Education in Krakow, Jana Pawla II 78, 31-571 Krakow, Poland
| | - Paulina Mazur-Kurach
- Department of Sports Medicine and Human Nutrition, Institute of Biomedical Sciences, University School of Physical Education in Krakow, Jana Pawla II 78, 31-571 Krakow, Poland; (P.M.-K.); (Z.S.); (B.F.)
| | - Zbigniew Szyguła
- Department of Sports Medicine and Human Nutrition, Institute of Biomedical Sciences, University School of Physical Education in Krakow, Jana Pawla II 78, 31-571 Krakow, Poland; (P.M.-K.); (Z.S.); (B.F.)
| | - Barbara Frączek
- Department of Sports Medicine and Human Nutrition, Institute of Biomedical Sciences, University School of Physical Education in Krakow, Jana Pawla II 78, 31-571 Krakow, Poland; (P.M.-K.); (Z.S.); (B.F.)
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Behrens M, Gube M, Chaabene H, Prieske O, Zenon A, Broscheid KC, Schega L, Husmann F, Weippert M. Fatigue and Human Performance: An Updated Framework. Sports Med 2023; 53:7-31. [PMID: 36258141 PMCID: PMC9807493 DOI: 10.1007/s40279-022-01748-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/24/2022] [Indexed: 01/12/2023]
Abstract
Fatigue has been defined differently in the literature depending on the field of research. The inconsistent use of the term fatigue complicated scientific communication, thereby limiting progress towards a more in-depth understanding of the phenomenon. Therefore, Enoka and Duchateau (Med Sci Sports Exerc 48:2228-38, 2016, [3]) proposed a fatigue framework that distinguishes between trait fatigue (i.e., fatigue experienced by an individual over a longer period of time) and motor or cognitive task-induced state fatigue (i.e., self-reported disabling symptom derived from the two interdependent attributes performance fatigability and perceived fatigability). Thereby, performance fatigability describes a decrease in an objective performance measure, while perceived fatigability refers to the sensations that regulate the integrity of the performer. Although this framework served as a good starting point to unravel the psychophysiology of fatigue, several important aspects were not included and the interdependence of the mechanisms driving performance fatigability and perceived fatigability were not comprehensively discussed. Therefore, the present narrative review aimed to (1) update the fatigue framework suggested by Enoka and Duchateau (Med Sci Sports Exerc 48:2228-38, 2016, [3]) pertaining the taxonomy (i.e., cognitive performance fatigue and perceived cognitive fatigue were added) and important determinants that were not considered previously (e.g., effort perception, affective valence, self-regulation), (2) discuss the mechanisms underlying performance fatigue and perceived fatigue in response to motor and cognitive tasks as well as their interdependence, and (3) provide recommendations for future research on these interactions. We propose to define motor or cognitive task-induced state fatigue as a psychophysiological condition characterized by a decrease in motor or cognitive performance (i.e., motor or cognitive performance fatigue, respectively) and/or an increased perception of fatigue (i.e., perceived motor or cognitive fatigue). These dimensions are interdependent, hinge on different determinants, and depend on body homeostasis (e.g., wakefulness, core temperature) as well as several modulating factors (e.g., age, sex, diseases, characteristics of the motor or cognitive task). Consequently, there is no single factor primarily determining performance fatigue and perceived fatigue in response to motor or cognitive tasks. Instead, the relative weight of each determinant and their interaction are modulated by several factors.
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Affiliation(s)
- Martin Behrens
- Department of Sport Science, Institute III, Otto-Von-Guericke University Magdeburg, Zschokkestraße 32, 39104, Magdeburg, Germany.
- Department of Orthopedics, Rostock University Medical Center, Rostock, Germany.
| | - Martin Gube
- Department of Sport Science, University of Rostock, Rostock, Germany
| | - Helmi Chaabene
- Department of Sports and Health Sciences, Faculty of Human Sciences, University of Potsdam, Potsdam, Germany
| | - Olaf Prieske
- Division of Exercise and Movement, University of Applied Sciences for Sports and Management Potsdam, Potsdam, Germany
| | - Alexandre Zenon
- Institut de Neurosciences Cognitives et Intégratives d'Aquitaine (INCIA)-UMR 5287, CNRS, University of Bordeaux, Bordeaux, France
| | - Kim-Charline Broscheid
- Department of Sport Science, Institute III, Otto-Von-Guericke University Magdeburg, Zschokkestraße 32, 39104, Magdeburg, Germany
| | - Lutz Schega
- Department of Sport Science, Institute III, Otto-Von-Guericke University Magdeburg, Zschokkestraße 32, 39104, Magdeburg, Germany
| | | | - Matthias Weippert
- Department of Sport Science, University of Rostock, Rostock, Germany
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Carbohydrate Mouth Rinse and Spray Improve Prolonged Exercise Performance in Recreationally Trained Male College Students. Sports (Basel) 2022; 10:sports10040051. [PMID: 35447861 PMCID: PMC9033104 DOI: 10.3390/sports10040051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 03/22/2022] [Accepted: 03/23/2022] [Indexed: 02/04/2023] Open
Abstract
Mouth rinsing with a carbohydrate (CHO) solution has emerged as a sports nutrition strategy to increase endurance performance. This study aimed to clarify the effects of two forms of CHO sensing in the mouth (i.e., CHO mouth rinse (CMR) and CHO mouth spray (CMS)) on exercise performance during prolonged exercise, including ultra-high intensity intermittent exercise over time. We conducted the following experimental trials: (1) 6% glucose solution (G), (2) 6% CMR, (3) 6% CMS, and (4) water (WAT). These trials were conducted at least 1 week apart in a randomized crossover design. Eight male college students performed constant-load exercise for 60 min (intensity 40% VO2peak), four sets of the Wingate test (three 30 s Wingate tests with a 4 min recovery between each test), and a constant-load exercise for 30 min (intensity 40% VO2peak). The mean exercise power output (Watt), ratings of perceived exertion, and blood glucose levels were measured. We found that the mean power values of the CMR and CMS in the third and fourth sets was significantly higher than that of WAT (p < 0.05), and that the G trial did not show a significant difference from any other trial. Thus, when compared to G or WAT, CMR and CMS can help improve endurance exercise performance.
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Noakes TD. What Is the Evidence That Dietary Macronutrient Composition Influences Exercise Performance? A Narrative Review. Nutrients 2022; 14:862. [PMID: 35215511 PMCID: PMC8875928 DOI: 10.3390/nu14040862] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 01/25/2022] [Accepted: 01/25/2022] [Indexed: 01/06/2023] Open
Abstract
The introduction of the needle muscle biopsy technique in the 1960s allowed muscle tissue to be sampled from exercising humans for the first time. The finding that muscle glycogen content reached low levels at exhaustion suggested that the metabolic cause of fatigue during prolonged exercise had been discovered. A special pre-exercise diet that maximized pre-exercise muscle glycogen storage also increased time to fatigue during prolonged exercise. The logical conclusion was that the athlete's pre-exercise muscle glycogen content is the single most important acutely modifiable determinant of endurance capacity. Muscle biochemists proposed that skeletal muscle has an obligatory dependence on high rates of muscle glycogen/carbohydrate oxidation, especially during high intensity or prolonged exercise. Without this obligatory carbohydrate oxidation from muscle glycogen, optimum muscle metabolism cannot be sustained; fatigue develops and exercise performance is impaired. As plausible as this explanation may appear, it has never been proven. Here, I propose an alternate explanation. All the original studies overlooked one crucial finding, specifically that not only were muscle glycogen concentrations low at exhaustion in all trials, but hypoglycemia was also always present. Here, I provide the historical and modern evidence showing that the blood glucose concentration-reflecting the liver glycogen rather than the muscle glycogen content-is the homeostatically-regulated (protected) variable that drives the metabolic response to prolonged exercise. If this is so, nutritional interventions that enhance exercise performance, especially during prolonged exercise, will be those that assist the body in its efforts to maintain the blood glucose concentration within the normal range.
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Affiliation(s)
- Timothy David Noakes
- Department of Applied Design, Cape Peninsula University of Technology, Cape Town 8000, South Africa
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Taurine supplementation enhances endurance capacity by delaying blood glucose decline during prolonged exercise in rats. Amino Acids 2022; 54:251-260. [PMID: 35122528 PMCID: PMC8894168 DOI: 10.1007/s00726-021-03110-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 11/22/2021] [Indexed: 11/01/2022]
Abstract
Taurine enhances physical performance; however, the underlying mechanism remains unclear. This study examined the effect of taurine on the overtime dynamics of blood glucose concentration (BGC) during endurance exercise in rats. Male F344 rats were subjected to transient treadmill exercise until exhaustion following 3 weeks of taurine supplementation or non-supplementation (TAU and CON groups). Every 10 min during exercise, BGC was measured in blood collected through cannulation of the jugular vein. Gluconeogenesis-, lipolysis-, and fatty acid oxidation-related factors in the plasma, liver, and skeletal muscles were also analyzed after 120-min run. Exercise time to exhaustion was significantly longer with taurine supplementation. BGC in the two groups significantly increased by 40 min and gradually and significantly decreased toward the respective exhaustion point. The decline in BGC from the peak at 40 min was significantly slower in the TAU group. The time when the once-increased BGC regressed to the 0-time level was significantly and positively correlated with exercise time until exhaustion. At the 120-min point, where the difference in BGC between the two groups was most significant, plasma free fatty acid concentration and acetyl-carnitine and N-acetyltaurine concentrations in skeletal muscle were significantly higher in the TAU group, whereas glycogen and glucogenic amino acid concentrations and G6Pase activity in the liver were not different between the two groups. Taurine supplementation enhances endurance capacity by delaying the decrease in BGC toward exhaustion through increases of lipolysis in adipose tissues and fatty acid oxidation in skeletal muscles during endurance exercise.
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Bourdas DI, Souglis A, Zacharakis ED, Geladas ND, Travlos AK. Meta-Analysis of Carbohydrate Solution Intake during Prolonged Exercise in Adults: From the Last 45+ Years' Perspective. Nutrients 2021; 13:4223. [PMID: 34959776 PMCID: PMC8704222 DOI: 10.3390/nu13124223] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/02/2021] [Accepted: 11/22/2021] [Indexed: 12/17/2022] Open
Abstract
Carbohydrate (CHO) supplementation during prolonged exercise postpones fatigue. However, the optimum administration timing, dosage, type of CHO intake, and possible interaction of the ergogenic effect with athletes' cardiorespiratory fitness (CRF) are not clear. Ninety-six studies (from relevant databases based on predefined eligibility criteria) were selected for meta-analysis to investigate the acute effect of ≤20% CHO solutions on prolonged exercise performance. The between-subject standardized mean difference [SMD = ([mean post-value treatment group-mean post-value control group]/pooled variance)] was assessed. Overall, SMD [95% CI] of 0.43 [0.35, 0.51] was significant (p < 0.001). Subgroup analysis showed that SMD was reduced as the subjects' CRF level increased, with a 6-8% CHO solution composed of GL:FRU improving performance (exercise: 1-4 h); administration during the event led to a superior performance compared to administration before the exercise, with a 6-8% single-source CHO solution increasing performance in intermittent and 'stop and start' sports and an ~6% CHO solution appearing beneficial for 45-60 min exercises, but there were no significant differences between subjects' gender and age groups, varied CHO concentrations, doses, or types in the effect measurement. The evidence found was sound enough to support the hypothesis that CHO solutions, when ingested during endurance exercise, have ergogenic action and a possible crossover interaction with the subject's CRF.
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Affiliation(s)
- Dimitrios I. Bourdas
- Section of Sport Medicine & Biology of Exercise, School of Physical Education and Sports Science, National and Kapodistrian University of Athens, 41 Ethnikis Antistasis, 17237 Athens, Greece;
| | - Athanasios Souglis
- Section of Didactics and Coaching in Sport Games, School of Physical Education & Sport Science, National and Kapodistrian University of Athens, 41 Ethnikis Antistasis, 17237 Athens, Greece; (A.S.); (E.D.Z.)
| | - Emmanouil D. Zacharakis
- Section of Didactics and Coaching in Sport Games, School of Physical Education & Sport Science, National and Kapodistrian University of Athens, 41 Ethnikis Antistasis, 17237 Athens, Greece; (A.S.); (E.D.Z.)
| | - Nickos D. Geladas
- Section of Sport Medicine & Biology of Exercise, School of Physical Education and Sports Science, National and Kapodistrian University of Athens, 41 Ethnikis Antistasis, 17237 Athens, Greece;
| | - Antonios K. Travlos
- Department of Sports Organization and Management, Faculty of Human Movement and Quality of Life Sciences, University of Peloponnese, Efstathiou and Stamatikis Valioti & Plataion Avenue, 23100 Tripoli, Greece;
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Paris HL, Sinai EC, Shei RJ, Keller AM, Mickleborough TD. The influence of carbohydrate ingestion on peripheral and central fatigue during exercise in hypoxia: A narrative review. Eur J Sport Sci 2021; 21:1423-1435. [PMID: 33106121 PMCID: PMC8140067 DOI: 10.1080/17461391.2020.1842512] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Hypoxia impairs aerobic performance by accelerating fatiguing processes. These processes may originate from sites either distal (peripheral) or proximal (central) to the neuromuscular junction, though these are not mutually exclusive. Peripheral mechanisms include decrements in muscle glycogen or fluctuations in intramuscular metabolites, whereas central responses commonly refer to reductions in central motor drive elicited by alterations in blood glucose and neurotransmitter concentrations as well as arterial hypoxemia. Hypoxia may accelerate both peripheral and central pathways of fatigue, with the level of hypoxia strongly dictating the degree and primary locus of impairment. As more people journey to hypoxic settings for work and recreation, developing strategies to improve work capacity in these environments becomes increasingly relevant. Given that sea level performance improves with nutritional interventions such as carbohydrate (CHO) ingestion, a similar strategy may prove effective in delaying fatigue in hypoxia, particularly considering how the metabolic pathways enhanced with CHO supplementation overlap the fatiguing pathways upregulated in hypoxia. Many questions regarding the relationship between CHO, hypoxia, and fatigue remain unanswered, including specifics on when to ingest, what to ingest, and how varying altitudes influence supplementation effectiveness. Therefore, the purpose of this narrative review is to examine the peripheral and central mechanisms contributing to fatigue during aerobic exercise at varying degrees of hypoxia and to assess the role of CHO ingestion in attenuating fatigue onset.
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Affiliation(s)
- Hunter L Paris
- Department of Sports Medicine, Pepperdine University, Malibu, CA, USA
| | - Erin C Sinai
- Department of Sports Medicine, Pepperdine University, Malibu, CA, USA
| | - Ren-Jay Shei
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, and Gregory Fleming James Cystic Fibrosis Research Center, University of Alabama at Birmingham, Birmingham, AL, USA
| | | | - Timothy D Mickleborough
- Department of Kinesiology, School of Public Health-Bloomington, Indiana University, Bloomington, IN, USA
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Liu L, Zhang Y, Liu T, Ke C, Huang J, Fu Y, Lin Z, Chen F, Wu X, Chen Q. Pyrroloquinoline quinone protects against exercise-induced fatigue and oxidative damage via improving mitochondrial function in mice. FASEB J 2021; 35:e21394. [PMID: 33710654 DOI: 10.1096/fj.202001977rr] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 01/08/2021] [Accepted: 01/08/2021] [Indexed: 12/23/2022]
Abstract
Pyrroloquinoline quinone (PQQ) has a variety of biological functions. However, rare attention has been paid to its effects on exercise-induced damage. Here, we assessed the potential protective effects of PQQ against the fatigue and oxidative damage caused by repeated exhaustive exercise, and studied the underlying mechanism. The models for exercise-induced fatigue were established, and the parameters were measured, including the time to exhaustion (TTE), biochemical indicators, the expression of nuclear factor kappa B (NF-κB) and inflammatory cytokines and so on. Besides, the mitochondrial function was evaluated by the morphology, membrane potential, respiratory function, adenosine triphosphate (ATP) levels, and the application of the mitochondrial complex I inhibitor. The results demonstrate that PQQ prolongs TTE, causes the decrease in the activity of serum creatine kinase and lactate dehydrogenase, increases the activity of antioxidant enzymes, inhibits the production of reactive oxygen species (ROS) and malondialdehyde (MDA), and diminishes the over expression of NF-κB (p65) and inflammatory mediators. Furthermore, PQQ preserves normal mitochondrial function. Particularly, PQQ reduces the accumulation of ROS triggered by the mitochondrial complex I inhibitor. These data suggest that PQQ can significantly protect mice from exercise-induced fatigue and oxidative damage by improving mitochondrial function. These data also suggest that PQQ controls mitochondrial activity through directly affecting the NADH dehydrogenase.
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Affiliation(s)
- Lixia Liu
- Fujian Key Laboratory of Innate Immune Biology, Biomedical Research Center of South China, Fujian Normal University, Fuzhou, Funjian, China.,School of Physical Education and Sport Science, Fujian Normal University, Fuzhou, Fujian, China.,The Key Laboratory of General Administration of Sport of China, Fujian Normal University, Fuzhou, Fujian, China.,Fujian Key Laboratory of Sports and Health, Fujian Normal University, Fuzhou, Fujian, China
| | - Yingyong Zhang
- School of Physical Education and Sport Science, Fujian Normal University, Fuzhou, Fujian, China
| | - Tao Liu
- School of Physical Education and Sport Science, Fujian Normal University, Fuzhou, Fujian, China
| | - Chongrong Ke
- College of Life Science, Fujian Normal University, Fuzhou, Fujian, China.,National Engineering Research Center of Industrial Microbiology and Fermentation Technology, Fujian Normal University, Fuzhou, Fujian, China
| | - Jianzhong Huang
- College of Life Science, Fujian Normal University, Fuzhou, Fujian, China.,National Engineering Research Center of Industrial Microbiology and Fermentation Technology, Fujian Normal University, Fuzhou, Fujian, China
| | - Yajuan Fu
- Fujian Key Laboratory of Innate Immune Biology, Biomedical Research Center of South China, Fujian Normal University, Fuzhou, Funjian, China.,College of Life Science, Fujian Normal University, Fuzhou, Fujian, China
| | - Zhang Lin
- Fujian Key Laboratory of Innate Immune Biology, Biomedical Research Center of South China, Fujian Normal University, Fuzhou, Funjian, China.,College of Life Science, Fujian Normal University, Fuzhou, Fujian, China
| | - Fengjuan Chen
- School of Physical Education and Sport Science, Fujian Normal University, Fuzhou, Fujian, China
| | - Xiuqin Wu
- School of Physical Education and Sport Science, Fujian Normal University, Fuzhou, Fujian, China.,The Key Laboratory of General Administration of Sport of China, Fujian Normal University, Fuzhou, Fujian, China
| | - Qi Chen
- Fujian Key Laboratory of Innate Immune Biology, Biomedical Research Center of South China, Fujian Normal University, Fuzhou, Funjian, China.,College of Life Science, Fujian Normal University, Fuzhou, Fujian, China
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Naderi A, Samanipour MH, Sarshin A, Forbes SC, Koozehchian MS, Franchini E, Reale R, Berjisian E, de Oliveira EP, Miraftabi H, Sharafshadeh MS, Rezaei S. Effects of two different doses of carbohydrate ingestion on taekwondo-related performance during a simulated tournament. J Int Soc Sports Nutr 2021; 18:40. [PMID: 34044858 PMCID: PMC8161610 DOI: 10.1186/s12970-021-00434-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 04/20/2021] [Indexed: 12/19/2022] Open
Abstract
Background Carbohydrate (CHO) ingestion enhances exercise performance; however, the efficacy of CHO intake on repeated bouts of exercise simulating a taekwondo tournament is unknown. Therefore, the purpose was to compare the effects of two different doses of CHO on a sports-specific kicking test during a simulated taekwondo tournament compared to placebo (PLA). Methods In a double-blind, randomized-placebo controlled, cross-over trial, eleven junior male professional taekwondo athletes (age: 16 ± 0.8 years, body mass: 55.3 ± 7.3 kg) ingested one of three solutions: (i) high dose (C45): 45 g of CHO (60 g∙h− 1), (ii) low dose (C22.5): 22.5 g of CHO (30 g∙h− 1; both solutions containing 2:1 glucose:fructose), or a PLA immediately following each kicking test. The kicking test was repeated 5 times, separated by 45 mins of rest, simulating a typical taekwondo competition day. Ratings of perceived exertion (RPE) and gastrointestinal discomfort (GI) scores were collected immediately after, and blood glucose before each test. Results The results revealed that C45 and C22.5 did not improve total, successful, or percentage of successful kicks compared to PLA (p > 0.05). Blood glucose was significantly higher following both CHO conditions compared with PLA across all five tests (p < 0.05). There were no differences between treatments or across tests for RPE (p > 0.05). Conclusion CHO intake, independent of the dose, did not alter taekwondo kick performance during a simulated taekwondo tournament.
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Affiliation(s)
- Alireza Naderi
- Department of Sport Physiology, Boroujerd Branch, Islamic Azad University, Boroujerd, Iran.
| | | | - Amir Sarshin
- Department of Exercise Physiology, Karaj Branch, Islamic Azad University, Karaj, Iran
| | - Scott C Forbes
- Faculty of Education, Department of Physical Education Studies, Brandon University, Brandon, MB, R7A6A9, Canada
| | - Majid S Koozehchian
- Department of Kinesiology, Jacksonville State University, Jacksonville, AL, 36265, USA
| | - Emerson Franchini
- School of Physical Education and Sport, University of São Paulo (USP), São Paulo, Brazil
| | - Reid Reale
- UFC Performance Institute, Shanghai, China
| | - Erfan Berjisian
- Department of Exercise Physiology, Faculty of Physical Education and Sport Sciences, Tehran, Iran
| | - Erick P de Oliveira
- Laboratory of Nutrition, Exercise and Health (LaNES), School of Medicine, Federal University of Uberlandia (UFU), Uberlandia, Minas Gerais, Brazil
| | - Hossein Miraftabi
- Department of Exercise Physiology, Faculty of Physical Education and Sport Sciences, Tehran, Iran
| | | | - Sajjad Rezaei
- College of Health and Human Sciences, Charles Darwin University, Darwin, Australia
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Acute Effects of Warm-Up, Exercise and Recovery-Related Strategies on Assessments of Soccer Kicking Performance: A Critical and Systematic Review. Sports Med 2021; 51:661-705. [PMID: 33332012 DOI: 10.1007/s40279-020-01391-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND A number of reviews have collated information on the impact of warming-up, physical exertion and recovery strategies on physical, subjective and physiological markers in soccer players yet none have solely analyzed their potential effects on components of kicking performance. OBJECTIVE To systematically analyse the influence of warm-up, exercise and/or recovery-related strategies on kicking performance in male soccer players and provide a critical appraisal on research paradigm related to kicking testing constraints and data acquisition methods. METHODS A systematic literature search was performed (until July 2020) in PubMed, Web of Science, SPORTDiscus, Scopus and ProQuest. Studies in male soccer populations, which included the effects of warm-up routines, physical exercise and/or recovery-related interventions, reported on comparisons pre-post or between experimental conditions and that computed at least one measure of kicking kinematics and/or performance were considered. Methodological quality and risk of bias were determined for the included studies. Constraints related to kicking testing and data acquisition methods were also summarized and discussed. RESULTS Altogether, 52 studies were included. Of these, 10 examined the respective effects of a warm-up, 34 physical exercise, and 21 recovery-related strategies. The results of eight studies showed that lower limb kinematics, kicking accuracy or ball velocity were improved following warm-ups involving dynamic but not static stretching. Declines in ball velocity occurred notably following intermittent endurance or graded until exhaustion exercise (three studies in both cases) without inclusion of any ball skills. In contrast, conflicting evidence in five studies was observed regarding ball velocity following intermittent endurance exercise interspersed with execution of ball skills. Kicking accuracy was less frequently affected by physical exercise (remained stable across 14 of 19 studies). One investigation indicated that consumption of a carbohydrate beverage pre- and mid-exercise demonstrated benefits in counteracting the potentially deleterious consequences of exercise on ball velocity, while four studies reported conflicting results regarding kicking accuracy. Most evidence synthesized for the interventions demonstrated moderate level (77%) and unclear-to-high risk of bias in at least one item evaluated (98%). The main limitations identified across studies were kicks generally performed over short distances (50%), in the absence of opposition (96%), and following experimental instructions which did not concomitantly consider velocity and accuracy (62%). Also, notational-based metrics were predominantly used to obtain accuracy outcomes (54%). CONCLUSIONS The results from this review can help inform future research and practical interventions in an attempt to measure and optimise soccer kicking performance. However, given the risk of bias and a relative lack of strong evidence, caution is required when applying some of the current findings in practice. PROSPERO ID CRD42018096942.
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15
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Xie Q, Sun Y, Cao L, Chen L, Chen J, Cheng X, Wang C. Antifatigue and antihypoxia activities of oligosaccharides and polysaccharides from Codonopsis pilosula in mice. Food Funct 2021; 11:6352-6362. [PMID: 32608442 DOI: 10.1039/d0fo00468e] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Codonopsis pilosula is a traditional Chinese medicine and food supplement that is widely used in China. This study aimed to investigate the antifatigue and antihypoxia activities of different extracts and fractions from C. pilosula, including ethanol extract (ETH), water extract (WAT), polysaccharides (POL), inulin (INU) and oligosaccharides (OLI). Different extracts and fractions were orally administered to mice at the doses of 0.25, 0.5 and 1.0 g kg-1 once a day for 21 days. Antifatigue activity was assessed through the weight-loaded swimming test on the 21st day, and antihypoxia activity was evaluated through the normobarie hypoxia test on the following day. Finally, biochemical parameters, such as liver glycogen (LG), muscle glycogen (MG), blood urea nitrogen (BUN), lactic dehydrogenase (LDH), malondialdehyde (MDA), and glutathione (GSH) levels, were determined. The results showed that, compared with the control treatment, only POL treatment significantly prolonged the swimming time of the mice. POL groups had the strongest hypoxia tolerance, followed by the OLI and WAT groups. The levels of LG and MG were significantly increased by treatment with POL at the doses of 0.5 and 1.0 g kg-1, whereas BUN and LDH levels in POL groups were significantly lower than those in the control group. MDA under POL and OLI treatment was significantly lower than that under the control treatment. In addition, treatments with POL and OLI, except for treatment with a low dose of OLI, significantly increased GSH levels. In conclusion, POL could efficiently enhance antifatigue and antihypoxia abilities by increasing energy resources, decreasing detrimental metabolite accumulation, and enhancing antioxidant activity. OLI could improve antihypoxia activity by preventing lipid peroxidation and enhancing antioxidant activity.
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Affiliation(s)
- Qi Xie
- Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine; The MOE Key Laboratory for Standardization of Chinese Medicines and The SATCM Key Laboratory for New Resources and Quality Evaluation of Chinese Medicines, Shanghai R&D Center for Standardization of Chinese Medicines, 1200 Cailun Road, Shanghai 201203, China.
| | - Yuting Sun
- Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine; The MOE Key Laboratory for Standardization of Chinese Medicines and The SATCM Key Laboratory for New Resources and Quality Evaluation of Chinese Medicines, Shanghai R&D Center for Standardization of Chinese Medicines, 1200 Cailun Road, Shanghai 201203, China.
| | - Lanlan Cao
- Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine; The MOE Key Laboratory for Standardization of Chinese Medicines and The SATCM Key Laboratory for New Resources and Quality Evaluation of Chinese Medicines, Shanghai R&D Center for Standardization of Chinese Medicines, 1200 Cailun Road, Shanghai 201203, China.
| | - Liangni Chen
- Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine; The MOE Key Laboratory for Standardization of Chinese Medicines and The SATCM Key Laboratory for New Resources and Quality Evaluation of Chinese Medicines, Shanghai R&D Center for Standardization of Chinese Medicines, 1200 Cailun Road, Shanghai 201203, China.
| | - Jie Chen
- Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine; The MOE Key Laboratory for Standardization of Chinese Medicines and The SATCM Key Laboratory for New Resources and Quality Evaluation of Chinese Medicines, Shanghai R&D Center for Standardization of Chinese Medicines, 1200 Cailun Road, Shanghai 201203, China.
| | - Xuemei Cheng
- Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine; The MOE Key Laboratory for Standardization of Chinese Medicines and The SATCM Key Laboratory for New Resources and Quality Evaluation of Chinese Medicines, Shanghai R&D Center for Standardization of Chinese Medicines, 1200 Cailun Road, Shanghai 201203, China.
| | - Changhong Wang
- Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine; The MOE Key Laboratory for Standardization of Chinese Medicines and The SATCM Key Laboratory for New Resources and Quality Evaluation of Chinese Medicines, Shanghai R&D Center for Standardization of Chinese Medicines, 1200 Cailun Road, Shanghai 201203, China.
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16
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Muscle Glycogen Metabolism and High-Intensity Exercise Performance: A Narrative Review. Sports Med 2021; 51:1855-1874. [PMID: 33900579 DOI: 10.1007/s40279-021-01475-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/08/2021] [Indexed: 02/06/2023]
Abstract
Muscle glycogen is the main substrate during high-intensity exercise and large reductions can occur after relatively short durations. Moreover, muscle glycogen is stored heterogeneously and similarly displays a heterogeneous and fiber-type specific depletion pattern with utilization in both fast- and slow-twitch fibers during high-intensity exercise, with a higher degradation rate in the former. Thus, depletion of individual fast- and slow-twitch fibers has been demonstrated despite muscle glycogen at the whole-muscle level only being moderately lowered. In addition, muscle glycogen is stored in specific subcellular compartments, which have been demonstrated to be important for muscle function and should be considered as well as global muscle glycogen availability. In the present review, we discuss the importance of glycogen metabolism for single and intermittent bouts of high-intensity exercise and outline possible underlying mechanisms for a relationship between muscle glycogen and fatigue during these types of exercise. Traditionally this relationship has been attributed to a decreased ATP resynthesis rate due to inadequate substrate availability at the whole-muscle level, but emerging evidence points to a direct coupling between muscle glycogen and steps in the excitation-contraction coupling including altered muscle excitability and calcium kinetics.
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17
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Rollo I, Gonzalez JT, Fuchs CJ, van Loon LJC, Williams C. Primary, Secondary, and Tertiary Effects of Carbohydrate Ingestion During Exercise. Sports Med 2021; 50:1863-1871. [PMID: 32936440 PMCID: PMC8159838 DOI: 10.1007/s40279-020-01343-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The purpose of this current opinion paper is to describe the journey of ingested carbohydrate from 'mouth to mitochondria' culminating in energy production in skeletal muscles during exercise. This journey is conveniently described as primary, secondary, and tertiary events. The primary stage is detection of ingested carbohydrate by receptors in the oral cavity and on the tongue that activate reward and other centers in the brain leading to insulin secretion. After digestion, the secondary stage is the transport of monosaccharides from the small intestine into the systemic circulation. The passage of these monosaccharides is facilitated by the presence of various transport proteins. The intestinal mucosa has carbohydrate sensors that stimulate the release of two 'incretin' hormones (GIP and GLP-1) whose actions range from the secretion of insulin to appetite regulation. Most of the ingested carbohydrate is taken up by the liver resulting in a transient inhibition of hepatic glucose release in a dose-dependent manner. Nonetheless, the subsequent increased hepatic glucose (and lactate) output can increase exogenous carbohydrate oxidation rates by 40-50%. The recognition and successful distribution of carbohydrate to the brain and skeletal muscles to maintain carbohydrate oxidation as well as prevent hypoglycaemia underpins the mechanisms to improve exercise performance.
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Affiliation(s)
- Ian Rollo
- Gatorade Sports Science Institute, PepsiCo Life Sciences, Global R&D, Leicestershire, UK. .,School of Sports Exercise and Health Sciences, Loughborough University, Loughborough, UK.
| | | | - Cas J Fuchs
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Luc J C van Loon
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Clyde Williams
- School of Sports Exercise and Health Sciences, Loughborough University, Loughborough, UK
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18
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Baldassarre R, Ieno C, Bonifazi M, Di Castro A, Gianfelici A, Piacentini MF. Carbohydrate supplementation during a simulated 10-km open water swimming race: effects on physiological, perceptual parameters and performance. Eur J Sport Sci 2021; 22:390-398. [PMID: 33487101 DOI: 10.1080/17461391.2021.1880644] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The aim of the present study was to test the effect of carbohydrate ingestion, simulating a 10-km open water race competition on energy cost (Csw), perceived exertion (RPE), heart rate (HR), stroke rate (SR) and performance. We hypothesized that carbohydrate ingestion would reduce Csw and RPE in elite open water swimmers (OW-swimmers) and improve performance. Eight elite OW-swimmers swam for 3 × 30 min with 20-s of interval necessary to collect data in the swimming flume at a pre-set pace corresponding to their 10-km race pace, followed by a time to exhaustion test (TTE) at 100% of the peak oxygen uptake (V̇O2peak). During the set, OW-swimmers ingested 45-g of carbohydrates (CHO) in 550-mL of water (8% solution) during each of the two intervals or a placebo solution (PLA). HR, RPE, V̇O2 and SR were measured. Shapiro-Wilk test was used to verify the normal distribution of data. Two-way repeated measures ANOVA and t-test was performed (p < 0.05). A significant difference emerged in TTE between the trials (169.00 ± 91.06 s in CHO; 102.31 ± 57.47 s in PLA). HR, RPE and SR increased during the TTE but did not differ between trials. Csw did not show a significant main effect between the two conditions and in time course in both conditions. CHO ingestion significantly increased TTE at 100% of V̇O2peak after 90-min of swimming at 10-km race pace. These findings indicate that CHO intake during a 10-km open water swimming competition should have a beneficial impact on performance in the final part of the race.
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Affiliation(s)
| | - Cristian Ieno
- Department of Movement, Human and Health Sciences, University of Rome Foro Italico, Rome, Italy
| | - Marco Bonifazi
- Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy.,Italian Swimming Federation, Rome, Italy
| | - Andrea Di Castro
- Sport Science Institute, Italian National Olympic Committee, Rome, Italy
| | - Antonio Gianfelici
- Sport Science Institute, Italian National Olympic Committee, Rome, Italy
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Newell ML, Macgregor LJ, Galloway SDR, Hunter AM. Prolonged cycling exercise alters neural control strategy, irrespective of carbohydrate dose ingested. TRANSLATIONAL SPORTS MEDICINE 2021. [DOI: 10.1002/tsm2.187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Michael L. Newell
- School of Sport Science and Physical Activity University of Bedfordshire Bedford England UK
| | - Lewis J. Macgregor
- Faculty of Health Sciences and Sport University of Stirling Stirling Scotland UK
| | | | - Angus M. Hunter
- Faculty of Health Sciences and Sport University of Stirling Stirling Scotland UK
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20
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Beretta-Piccoli M, Cescon C, D’Antona G. Evaluation of performance fatigability through surface EMG in health and muscle disease: state of the art. ARAB JOURNAL OF BASIC AND APPLIED SCIENCES 2020. [DOI: 10.1080/25765299.2020.1862985] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Affiliation(s)
- Matteo Beretta-Piccoli
- Criams-Sport Medicine Centre Voghera, University of Pavia, Pavia, Italy
- Rehabilitation Research Laboratory 2rLab, Department of Business Economics, Health and Social Care, University of Applied, Sciences and Arts of Southern Switzerland, Manno, Switzerland
| | - Corrado Cescon
- Rehabilitation Research Laboratory 2rLab, Department of Business Economics, Health and Social Care, University of Applied, Sciences and Arts of Southern Switzerland, Manno, Switzerland
| | - Giuseppe D’Antona
- Criams-Sport Medicine Centre Voghera, University of Pavia, Pavia, Italy
- Department of Public Health, Experimental and Forensic Medicine, University of Pavia, Pavia, Italy
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21
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Hargreaves M, Spriet LL. Skeletal muscle energy metabolism during exercise. Nat Metab 2020; 2:817-828. [PMID: 32747792 DOI: 10.1038/s42255-020-0251-4] [Citation(s) in RCA: 411] [Impact Index Per Article: 102.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 06/25/2020] [Indexed: 12/12/2022]
Abstract
The continual supply of ATP to the fundamental cellular processes that underpin skeletal muscle contraction during exercise is essential for sports performance in events lasting seconds to several hours. Because the muscle stores of ATP are small, metabolic pathways must be activated to maintain the required rates of ATP resynthesis. These pathways include phosphocreatine and muscle glycogen breakdown, thus enabling substrate-level phosphorylation ('anaerobic') and oxidative phosphorylation by using reducing equivalents from carbohydrate and fat metabolism ('aerobic'). The relative contribution of these metabolic pathways is primarily determined by the intensity and duration of exercise. For most events at the Olympics, carbohydrate is the primary fuel for anaerobic and aerobic metabolism. Here, we provide an overview of exercise metabolism and the key regulatory mechanisms ensuring that ATP resynthesis is closely matched to the ATP demand of exercise. We also summarize various interventions that target muscle metabolism for ergogenic benefit in athletic events.
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Affiliation(s)
- Mark Hargreaves
- Department of Physiology, University of Melbourne, Melbourne, Victoria, Australia.
| | - Lawrence L Spriet
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada.
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22
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Intramuscular Mechanisms Mediating Adaptation to Low-Carbohydrate, High-Fat Diets during Exercise Training. Nutrients 2020; 12:nu12092496. [PMID: 32824957 PMCID: PMC7551624 DOI: 10.3390/nu12092496] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/15/2020] [Accepted: 08/17/2020] [Indexed: 12/01/2022] Open
Abstract
Interest in low-carbohydrate, high-fat (LCHF) diets has increased over recent decades given the theorized benefit of associated intramuscular adaptations and shifts in fuel utilization on endurance exercise performance. Consuming a LCHF diet during exercise training increases the availability of fat (i.e., intramuscular triglyceride stores; plasma free fatty acids) and decreases muscle glycogen stores. These changes in substrate availability increase reliance on fat oxidation for energy production while simultaneously decreasing reliance on carbohydrate oxidation for fuel during submaximal exercise. LCHF diet-mediated changes in substrate oxidation remain even after endogenous or exogenous carbohydrate availability is increased, suggesting that the adaptive response driving changes in fat and carbohydrate oxidation lies within the muscle and persists even when the macronutrient content of the diet is altered. This narrative review explores the intramuscular adaptations underlying increases in fat oxidation and decreases in carbohydrate oxidation with LCHF feeding. The possible effects of LCHF diets on protein metabolism and post-exercise muscle remodeling are also considered.
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23
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Suarsana IN, Utama IH, Kardena IM. Tempe extract reduces cell damage in the liver and kidneys after intensive physical exercise in rats. Vet World 2020; 13:1510-1516. [PMID: 33061220 PMCID: PMC7522934 DOI: 10.14202/vetworld.2020.1510-1516] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Accepted: 06/10/2020] [Indexed: 11/22/2022] Open
Abstract
Background and Aim: Cells of the liver and kidneys are perpetually exposed to free radicals from endogenous and exogenous sources. High-intensity physical exercise can induce oxidative stress. This study aimed to determine the effects of tempe extract on cell damage in the liver and kidneys of rats after intensive physical exercise. Materials and Methods: This study used five experimental groups: T0 (non-exercised control rats), T1 (rats made to exercise by swimming), and T2-T4 (rats made to exercise by swimming treated with 25, 50, and 100 mg/kg body weight tempe extract). The biochemical parameters that were analyzed included blood glucose, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), blood urea nitrogen (BUN), and creatinine levels. The morphology of liver and kidney tissues was histopathologically and immunohistochemically analyzed. Results: Tempe extract treatment reduced cell damage in the liver and kidney tissues of rats, characterized by decreased expression of caspase-3. In addition, the ALT, AST, ALP, creatinine, and BUN levels of rats were significantly lower in tempe extract-treated rats than in rats after swimming exercise alone. Conclusion: Tempe extract is capable of reducing cell damage and apoptosis in the liver and kidney cells of rats after intensive physical exercise and maintaining biochemical properties similar to the normal physiological state.
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Affiliation(s)
- I Nyoman Suarsana
- Laboratory of Biochemistry, Faculty of Veterinary Medicine, Udayana University, Denpasar, Indonesia
| | - Iwan Harjono Utama
- Laboratory of Biochemistry, Faculty of Veterinary Medicine, Udayana University, Denpasar, Indonesia
| | - I Made Kardena
- Laboratory of Pathology, Faculty of Veterinary Medicine, Udayana University, Denpasar, Bali, Indonesia
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Lactobacillus plantarum PS128 Improves Physiological Adaptation and Performance in Triathletes through Gut Microbiota Modulation. Nutrients 2020; 12:nu12082315. [PMID: 32752178 PMCID: PMC7468698 DOI: 10.3390/nu12082315] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/21/2020] [Accepted: 07/28/2020] [Indexed: 02/06/2023] Open
Abstract
A triathlon is an extremely high-intensity exercise and a challenge for physiological adaptation. A triathlete's microbiome might be modulated by diet, age, medical treatments, lifestyle, and exercise, thereby maintaining aerobiosis and optimum health and performance. Probiotics, prebiotics, and synbiotics have been reported to have health-promoting activities (e.g., immunoregulation and cancer prevention). However, few studies have addressed how probiotics affect the microbiota of athletes and how this translates into functional activities. In our previous study, we found that Lactobacillus plantarum PS128 could ameliorate inflammation and oxidative stress, with improved exercise performance. Thus, here we investigate how the microbiota of triathletes are altered by L. plantarum PS128 supplementation, not only for exercise performance but also for possible physiological adaptation. The triathletes were assigned to two groups: an L. plantarum 128 supplement group (LG, 3 × 1010 colony-forming units (CFU)/day) and a placebo group (PG). Both groups continued with their regular exercise training for the next 4 weeks. The endurance performance, body composition, biochemistries, blood cells, microbiota, and associated metabolites were further investigated. PS128 significantly increased the athletes' endurance, by about 130% as compared to the PG group, but there was no significant difference in maximal oxygen consumption (VO2max) and composition between groups. The PS128 supplementation (LG) modulated the athlete's microbiota with both significant decreases (Anaerotruncus, Caproiciproducens, Coprobacillus, Desulfovibrio, Dielma, Family_XIII, Holdemania, and Oxalobacter) and increases (Akkermansia, Bifidobacterium, Butyricimonas, and Lactobacillus), and the LG showed lower diversity when compared to the PG. Also, the short-chain fatty acids (SCFAs; acetate, propionate, and butyrate) of the LG were significantly higher than the PG, which might be a result of a modulation of the associated microbiota. In conclusion, PS128 supplementation was associated with an improvement on endurance running performance through microbiota modulation and related metabolites, but not in maximal oxygen uptake.
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Sánchez-Molina J, Tronero-Aguilera JF, Clemente-Suárez VJ. Psychophysiological respond in a swimming ultra-endurance event. J Sports Med Phys Fitness 2020; 61:140-145. [PMID: 32693561 DOI: 10.23736/s0022-4707.20.11201-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Ultra-endurance events under critical environmental conditions represent unique stress, resulting in acute marked adaptations to the cardiovascular, respiratory, metabolic and neuromuscular systems of the organism. In line with this, no studies in swimming events were found thus far. METHODS This research aimed to analyze the psychophysiological response of swimmers in an ultra-endurance swimming event. Changes in the rate of perceived exertion, blood lactate concentration, 1000m swimming time and cortical arousal were measured in 19 male volunteer swimmers (28.0±5.6 years; 175.0±7.9 cm; 70.1±7.8 kg) in 3 moments during a 24h swimming event. RESULTS We found a significant increase in lactate concentration after series 1, decreasing the values in series 2 and series 3. Cortical arousal decreased significantly in series 3 respect the basal sample. Rate of perceived exertion significantly increased in the swimming ultra-endurance event and 1000m swimming time was maintained during the series analyzed. CONCLUSIONS An ultra-endurance swimming event produced an increase in blood lactate concentration and rated of perceived exertion and a decrease in cortical arousal, not affecting average swimming velocity along the event.
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Affiliation(s)
| | - José F Tronero-Aguilera
- Faculty of Sports Sciences, European University of Madrid, Madrid, Spain.,Research Center in Applied Combat (CESCA), Toledo, Spain
| | - Vicente J Clemente-Suárez
- Faculty of Sports Sciences, European University of Madrid, Madrid, Spain - .,Research Center in Applied Combat (CESCA), Toledo, Spain.,Grupo de Investigación en Cultura, Educación y Sociedad (CULTEDUSOC), Coast University, Barranquilla, Colombia
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26
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Viribay A, Arribalzaga S, Mielgo-Ayuso J, Castañeda-Babarro A, Seco-Calvo J, Urdampilleta A. Effects of 120 g/h of Carbohydrates Intake during a Mountain Marathon on Exercise-Induced Muscle Damage in Elite Runners. Nutrients 2020; 12:E1367. [PMID: 32403259 PMCID: PMC7284742 DOI: 10.3390/nu12051367] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 05/07/2020] [Accepted: 05/09/2020] [Indexed: 12/17/2022] Open
Abstract
Background-exercise-induced muscle damage (EIMD) and internal exercise load are increased after competing in ultraendurance events such as mountain marathons. Adequate carbohydrate (CHO) intake during exercise optimizes athletic performance and could limit EIMD, reduce internal exercise load and, thus, improve recovery. Therefore, the aim of this study was to research into and compare the effects of high CHO intake (120 g/h) in terms of CHO intake recommendation (90 g/h) and regular CHO intake performed by ultraendurance athletes (60 g/h) during a mountain marathon, on exercise load and EIMD markers (creatine kinase (CK), lactate dehydrogenase (LDH), glutamic oxaloacetic transaminase (GOT), urea and creatinine). Materials and Methods-a randomized trial was carried out on 20 male elite runners who had previously undertaken nutritional and gut training, and who consumed different CHO dosages according to experimental (EXP-120 g/h), control (CON-90 g/h) and low CHO intake (LOW-60 g/h) groups during a ~4000 m cumulative slope mountain marathon. EIMD markers were analyzed before the race and 24 h afterwards. Internal exercise load was calculated based on rate of perceived exertion (RPE) during and after the marathon event. Results-internal exercise load during the mountain marathon was significantly lower (p = 0.019; η2p = 0.471) in EXP (3805 ± 281 AU) compared to LOW (4688 ± 705 AU) and CON (4692 ± 716 AU). Moreover, results revealed that the EXP group evidenced significantly lower CK (p = 0.019; η2p = 0.373), LDH (p < 0.001; η2p = 0.615) and GOT (p = 0.003; η2p = 0.500) values 24 h after the mountain marathon race compared to LOW and CON. Along these lines, EIMD and exercise load evidenced a close correlation (R = 0.742; p < 0.001). Conclusion: High CHO intake (120 g/h) during a mountain marathon could limit the EIMD observed by CK, LDH and GOT and internal exercise load compared to CHO ingestion of 60 and 90 g/h.
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Affiliation(s)
- Aitor Viribay
- Glut4Science, Physiology, Nutrition and Sport, 01004 Vitoria-Gasteiz, Spain;
| | - Soledad Arribalzaga
- Institute of Biomedicine (IBIOMED), Physiotherapy Department, University of Leon, Campus de Vegazana, 24071 Leon, Spain;
| | - Juan Mielgo-Ayuso
- Department of Biochemistry Molecular Biology and Physiology, Faculty of Health Sciences, University of Valladolid, 42004 Soria, Spain;
| | - Arkaitz Castañeda-Babarro
- Health, Physical Activity and Sports Science Laboratory, Department of Physical Activity and Sports, Faculty of Psychology and Education, University of Deusto, 48007 Bizkaia, Spain;
| | - Jesús Seco-Calvo
- Institute of Biomedicine (IBIOMED), Physiotherapy Department, University of Leon, Researcher at the Basque Country University, Campus de Vegazana, 24071 Leon, Spain;
| | - Aritz Urdampilleta
- Centro de Investigacion y de Formación ElikaEsport, 08290 Cerdanyola del Valles, Barcelona, Spain
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27
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Koma R, Terasawa N. Pre-Exercise Glucose Ingestion May Improve Endurance Capacity in East Asian Student Athletes with Lower Blood Glucose Response. J Nutr Sci Vitaminol (Tokyo) 2020; 66:150-157. [PMID: 32350176 DOI: 10.3177/jnsv.66.150] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The main purpose of this study was to investigate the influence of pre-exercise glucose ingestion after a 2.5-h fast on the endurance capacity and blood glucose response in East Asian athletes who is expected to have genetically low insulin response. A total of 8 Japanese student athletes ingested 1.5 g/kg body mass of glucose (G trial) or 0.5 g/kg body mass of artificial sweetener dissolved in water (P trial) 30 min before exercise test after consuming a standardized breakfast. The exercise test comprised 40 min cycling exercise at 50% maximal oxygen uptake (VO2max), immediately followed by cycling to exhaustion at 70% VO2max. Before analyzing the data, we grouped the subjects into two groups depending on whether they showed rapid increase in blood glucose at the onset of exercise (increase rate in LOW group is <20% and HIGH group is ≥20%) to evaluate subject's insulin response to glucose feeding. No subjects developed rebound hypoglycemia (<70 mg/dL) in the G trial of both group. Significantly higher blood glucose during exercise was recognized only in the G trial of LOW group. Although no significant difference was observed between the two trials of both group, cycling time to exhaustion in the LOW group tended to increase because of glucose ingestion. These results suggest that pre-exercise ingestion of glucose in East Asian student athletes does not induce rebound hypoglycemia regardless of difference in individual insulin responses. Furthermore, individuals with low insulin responses seem to improve endurance performance with glucose ingestion before exercise.
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Affiliation(s)
- Rikuhide Koma
- School of Regional Development Studies, Graduate School of Human and Socio-Environmental Studies, Kanazawa University
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28
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Li W, Luo C, Huang Y, Zhan J, Lei J, Li N, Huang X, Luo H. Evaluation of antifatigue and antioxidant activities of the marine microalgae Isochrysis galbana in mice. Food Sci Biotechnol 2020; 29:549-557. [PMID: 32296566 PMCID: PMC7142183 DOI: 10.1007/s10068-019-00694-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 09/12/2019] [Accepted: 09/20/2019] [Indexed: 01/28/2023] Open
Abstract
The present work aimed to estimate the possible anti-fatigue effect and potential mechanism of Isochrysis galbana (IG) in mice. The anti-fatigue activity of IG (100, 200, and 400 mg/kg) was elucidated by a weight-loaded forced swimming test, and the potential mechanism was explored by determination of fatigue-related biochemical parameters. The results showed that pretreatment with IG significantly extended the exhaustive swimming time and increased the levels of liver glycogen, muscle glycogen and blood glucose in a dose-dependent manner. Besides, the increased levels of alanine aminotransferase, aspartate aminotransferase, blood lactic acid, lactic dehydrogenase, creatine kinase, and blood urea nitrogen by exhausted swimming, were dramatically attenuated by pretreatment with IG. Furthermore, supplementation with IG significantly enhanced the glutathione peroxidase and superoxide dismutase levels, while attenuated the level of malonaldehyde. Taken together, IG possessed appreciable efficacy to alleviate fatigue, and the mechanism might be associated with favorably modulating the process of energy consumption, metabolism, and attenuating oxidative stress injury.
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Affiliation(s)
- Wenjie Li
- Department of Hematology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, 524001 People’s Republic of China
| | - Chaodan Luo
- Guangdong Provincial Key Laboratory of New Drug Development and Research of Chinese Medicine, Mathematical Engineering Academy of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, 510006 People’s Republic of China
| | - Yongmei Huang
- Marine Biomedical Research Institute, the Key Lab of Zhanjiang for R&D Marine Microbial Resources in the Beibu Gulf Rim, Guangdong Medical University, Zhanjiang, 524023 People’s Republic of China
| | - Jingting Zhan
- Chemistry Teaching and Research Section, the Key Lab of Zhanjiang for R&D Marine Microbial Resources in the Beibu Gulf Rim, Guangdong Medical University, Zhanjiang, 524023 People’s Republic of China
| | - Jinli Lei
- Chemistry Teaching and Research Section, the Key Lab of Zhanjiang for R&D Marine Microbial Resources in the Beibu Gulf Rim, Guangdong Medical University, Zhanjiang, 524023 People’s Republic of China
| | - Ning Li
- Department of Hematology, Affiliated Hospital of Guangdong Medical University, Zhanjiang, 524001 People’s Republic of China
| | - Xiaoqi Huang
- Guangdong Provincial Key Laboratory of New Drug Development and Research of Chinese Medicine, Mathematical Engineering Academy of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, 510006 People’s Republic of China
| | - Hui Luo
- Marine Biomedical Research Institute, the Key Lab of Zhanjiang for R&D Marine Microbial Resources in the Beibu Gulf Rim, Guangdong Medical University, Zhanjiang, 524023 People’s Republic of China
- Chemistry Teaching and Research Section, the Key Lab of Zhanjiang for R&D Marine Microbial Resources in the Beibu Gulf Rim, Guangdong Medical University, Zhanjiang, 524023 People’s Republic of China
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29
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Khong TK, Selvanayagam V, Yusof A. Effect of glucose and sodium chloride mouth rinses on neuromuscular fatigue: a preliminary study. Eur J Sport Sci 2020; 21:224-230. [PMID: 32056510 DOI: 10.1080/17461391.2020.1730980] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Carbohydrate (CHO) mouth rinse has been shown to improve endurance performance and maintain the central drive of contracting muscles. Salt (NaCl) mouth rinse solution, often used in dentistry to desensitise the oral cavity to pain, could also activate cortical areas of the brain. Hence, the objective of this preliminary study was to investigate whether CHO (glucose) and NaCl mouth rinses could attenuate the reduction in maximum voluntary contraction (MVC) and sustained MVC (sMVC) following an endurance exercise (30-minute cycling at 70% VO2max). Ten subjects (male, age: 22 ± 1 years, weight: 65.3 ± 12.4 kg, height: 164.5 ± 7.5 cm, VO2max: 48.3 ± 6.1 mL kg-1 min-1) completed three trials of 30-minute cycling exercise. In a randomised cross-over study, in each trial, the participants rinsed using either water, 6% glucose, or 6% NaCl solution for 5 s immediately prior to and every 10 min during the cycling exercise. The MVC and sMVC were measured pre and post cycling. Analysis of variance showed significant interaction and time effects for MVC, while for sMVC there was a significant interaction with time and group effects. Both MVC and sMVC were higher post cycling in the glucose and NaCl groups compared to the water group, which suggests that activation of glucose and NaCl oral receptors could better preserve post-exercise force production. This is the first study to show that NaCl mouth rinse can produce a comparable effect on glucose. Hence, mouth rinses may be able to activate other distinct pathways that could attenuate fatigue.
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Affiliation(s)
- Teng Keen Khong
- Centre of Sport and Exercise Sciences, University of Malaya, Kuala Lumpur, Malaysia.,Faculty of Applied Sciences, Department of Sports Sciences, Tunku Abdul Rahman University College, Kuala Lumpur, Malaysia
| | - Victor Selvanayagam
- Centre of Sport and Exercise Sciences, University of Malaya, Kuala Lumpur, Malaysia
| | - Ashril Yusof
- Centre of Sport and Exercise Sciences, University of Malaya, Kuala Lumpur, Malaysia
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30
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Zubac D, Šimunič B, Buoite Stella A, Morrison SA. Neuromuscular performance after rapid weight loss in Olympic-style boxers. Eur J Sport Sci 2019; 20:1051-1060. [PMID: 31744401 DOI: 10.1080/17461391.2019.1695954] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Abstract The present study investigated the effect of a 3% rapid weight loss (RWL) procedure on neuromuscular performance in elite, Olympic-style boxers. Nine boxers were randomly assigned to two experimental procedures (RWL and control, in a randomized counter-balance order) to perform 5-s maximum isometric voluntary contractions (MVC) of the dominant leg knee extensors prior to (MVC1), and following (MVC2), a sustained, isometric contraction at 70% MVC until exhaustion. The voluntary activation (VA) was determined using percutaneous muscle stimulation and interpolated twitch technique. High (at 80 Hz) and low (at 20 Hz) frequency tetanic impulses were also delivered before and after the sustained 70% MVC to assess peripheral fatigue. Hydration status, hemodynamic parameters, and lactate concentration were assessed throughout the study. Body-mass was reduced by ∼3% (during RWL) compared to control (p = .001). As a result of the RWL protocol, MVC1 force output was 12% lower and VA deficits of 7% were observed after the fatigue protocol compared to control (p = .001). Following RWL, time to exhaustion for the sustained 70% MVC was 69 ± 20 s compared to 86 ± 34 s for control (p = .020). Peak lactate production was 53% lower in RWL compared to control (p = .001). In conclusion, the 3% RWL procedure translated into significant decline in neuromuscular performance for both brief and sustained contractions in competitive boxers.
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Affiliation(s)
- Damir Zubac
- Faculty of Kinesiology, University of Split, Split, Croatia.,Science and Research Center Koper, Institute for Kinesiology Research, Koper, Slovenia
| | - Boštjan Šimunič
- Science and Research Center Koper, Institute for Kinesiology Research, Koper, Slovenia
| | - Alex Buoite Stella
- Department of Medicine, Surgery, and Health Sciences, University of Trieste, Trieste, Italy
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31
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Salvador AF, McKenna CF, Alamilla RA, Cloud RMT, Keeble AR, Miltko A, Scaroni SE, Beals JW, Ulanov AV, Dilger RN, Bauer LL, Broad EM, Burd NA. Potato ingestion is as effective as carbohydrate gels to support prolonged cycling performance. J Appl Physiol (1985) 2019; 127:1651-1659. [PMID: 31622159 PMCID: PMC6962613 DOI: 10.1152/japplphysiol.00567.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Carbohydrate (CHO) ingestion is an established strategy to improve endurance performance. Race fuels should not only sustain performance but also be readily digested and absorbed. Potatoes are a whole-food-based option that fulfills these criteria, yet their impact on performance remains unexamined. We investigated the effects of potato purée ingestion during prolonged cycling on subsequent performance vs. commercial CHO gel or a water-only condition. Twelve cyclists (70.7 ± 7.7 kg, 173 ± 8 cm, 31 ± 9 yr, 22 ± 5.1% body fat; means ± SD) with average peak oxygen consumption (V̇o2peak) of 60.7 ± 9.0 mL·kg−1·min−1 performed a 2-h cycling challenge (60–85% V̇o2peak) followed by a time trial (TT; 6 kJ/kg body mass) while consuming potato, gel, or water in a randomized-crossover design. The race fuels were administered with [U-13C6]glucose for an indirect estimate of gastric emptying rate. Blood samples were collected throughout the trials. Blood glucose concentrations were higher (P < 0.001) in potato and gel conditions compared with water condition. Blood lactate concentrations were higher (P = 0.001) after the TT completion in both CHO conditions compared with water condition. TT performance was improved (P = 0.032) in both potato (33.0 ± 4.5 min) and gel (33.0 ± 4.2 min) conditions compared with water condition (39.5 ± 7.9 min). Moreover, no difference was observed in TT performance between CHO conditions (P = 1.00). In conclusion, potato and gel ingestion equally sustained blood glucose concentrations and TT performance. Our results support the effective use of potatoes to support race performance for trained cyclists. NEW & NOTEWORTHY The ingestion of concentrated carbohydrate gels during prolonged exercise has been shown to promote carbohydrate availability and improve exercise performance. Our study aim was to expand and diversify race fueling menus for athletes by providing an evidence-based whole-food alternative to the routine ingestion of gels during training and competition. Our work shows that russet potato ingestion during prolonged cycling is as effective as carbohydrate gels to support exercise performance in trained athletes.
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Affiliation(s)
- Amadeo F Salvador
- Department of Kinesiology and Community Health, University of Illinois, Urbana, Illinois
| | - Colleen F McKenna
- Division of Nutritional Sciences, University of Illinois, Urbana, Illinois
| | - Rafael A Alamilla
- Department of Kinesiology and Community Health, University of Illinois, Urbana, Illinois
| | - Ryan M T Cloud
- Department of Kinesiology and Community Health, University of Illinois, Urbana, Illinois
| | - Alexander R Keeble
- Department of Kinesiology and Community Health, University of Illinois, Urbana, Illinois
| | - Adriana Miltko
- Department of Kinesiology and Community Health, University of Illinois, Urbana, Illinois
| | - Susannah E Scaroni
- Division of Nutritional Sciences, University of Illinois, Urbana, Illinois
| | - Joseph W Beals
- Division of Nutritional Sciences, University of Illinois, Urbana, Illinois
| | | | - Ryan N Dilger
- Division of Nutritional Sciences, University of Illinois, Urbana, Illinois.,Department of Animal Sciences, University of Illinois, Urbana, Illinois.,Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana, Illinois
| | - Laura L Bauer
- Department of Animal Sciences, University of Illinois, Urbana, Illinois
| | | | - Nicholas A Burd
- Department of Kinesiology and Community Health, University of Illinois, Urbana, Illinois.,Division of Nutritional Sciences, University of Illinois, Urbana, Illinois
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32
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Clark IE, Vanhatalo A, Thompson C, Joseph C, Black MI, Blackwell JR, Wylie LJ, Tan R, Bailey SJ, Wilkins BW, Kirby BS, Jones AM. Dynamics of the power-duration relationship during prolonged endurance exercise and influence of carbohydrate ingestion. J Appl Physiol (1985) 2019; 127:726-736. [PMID: 31295069 DOI: 10.1152/japplphysiol.00207.2019] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We tested the hypotheses that the parameters of the power-duration relationship, estimated as the end-test power (EP) and work done above EP (WEP) during a 3-min all-out exercise test (3MT), would be reduced progressively after 40 min, 80 min, and 2 h of heavy-intensity cycling and that carbohydrate (CHO) ingestion would attenuate the reduction in EP and WEP. Sixteen participants completed a 3MT without prior exercise (control), immediately after 40 min, 80 min, and 2 h of heavy-intensity exercise while consuming a placebo beverage, and also after 2 h of heavy-intensity exercise while consuming a CHO supplement (60 g/h CHO). There was no difference in EP measured without prior exercise (260 ± 37 W) compared with EP after 40 min (268 ± 39 W) or 80 min (260 ± 40 W) of heavy-intensity exercise; however, after 2 h EP was 9% lower compared with control (236 ± 47 W; P < 0.05). There was no difference in WEP measured without prior exercise (17.9 ± 3.3 kJ) compared with after 40 min of heavy-intensity exercise (16.1 ± 3.3 kJ), but WEP was lower (P < 0.05) than control after 80 min (14.7 ± 2.9 kJ) and 2 h (13.8 ± 2.7 kJ). Compared with placebo, CHO ingestion negated the reduction of EP following 2 h of heavy-intensity exercise (254 ± 49 W) but had no effect on WEP (13.5 ± 3.4 kJ). These results reveal a different time course for the deterioration of EP and WEP during prolonged endurance exercise and indicate that EP is sensitive to CHO availability.NEW & NOTEWORTHY The parameters of the power-duration relationship [critical power (CP) and the curvature constant (W')] have typically been considered to be static. Here we report the time course for reductions in CP and W', as estimated with the 3-min all-out cycle test, during 2 h of heavy-intensity exercise. We also show that carbohydrate ingestion during exercise preserves CP, but not W', without altering muscle glycogen depletion. These results provide new mechanistic and practical insight into the power-duration curve and its relationship to exercise-related fatigue development.
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Affiliation(s)
- Ida E Clark
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - Anni Vanhatalo
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - Christopher Thompson
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - Charlotte Joseph
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - Matthew I Black
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - Jamie R Blackwell
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - Lee J Wylie
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - Rachel Tan
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | - Stephen J Bailey
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
| | | | | | - Andrew M Jones
- Sport and Health Sciences, College of Life and Environmental Sciences, St. Luke's Campus, University of Exeter, Exeter, United Kingdom
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Pedroso JAB, Ramos-Lobo AM, Donato J. SOCS3 as a future target to treat metabolic disorders. Hormones (Athens) 2019; 18:127-136. [PMID: 30414080 DOI: 10.1007/s42000-018-0078-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 10/29/2018] [Indexed: 12/20/2022]
Abstract
The suppressors of cytokine signaling (SOCS) are a group of eight proteins responsible for preventing excessive cytokine signaling. Among this protein family, SOCS3 has received special attention. SOCS3 expression is important to control certain allergy autoimmune diseases. Furthermore, SOCS3 expression is elevated in obesity and it is involved in the inhibition of leptin and insulin signaling, two important hormones involved in the control of energy metabolism. Therefore, increased SOCS3 expression in obese individuals is associated with several metabolic disorders, including reduced energy expenditure, increased food intake and adiposity, and insulin and leptin resistance. In addition, recent studies found that SOCS3 expression regulates energy and glucose homeostasis in several metabolic conditions, such as pregnancy, caloric restriction, and refeeding. Importantly, attenuation of SOCS3 expression in most cases improves leptin and insulin sensitivity, leading to beneficial metabolic effects. This review aims to discuss the role of SOCS3 in the control of blood glucose levels as well as in energy homeostasis. The development of pharmacological compounds to inhibit SOCS3 activity and/or expression may represent a promising therapeutic approach to treat type 2 diabetes mellitus, obesity, and other metabolic imbalances.
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Affiliation(s)
- João A B Pedroso
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes, 1524, São Paulo, 05508-000, Brazil.
| | - Angela M Ramos-Lobo
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes, 1524, São Paulo, 05508-000, Brazil
| | - Jose Donato
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, Av. Prof. Lineu Prestes, 1524, São Paulo, 05508-000, Brazil
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34
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Review of exercise-induced physiological control models to explain the development of fatigue to improve sports performance and future trend. Sci Sports 2019. [DOI: 10.1016/j.scispo.2018.10.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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35
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Anticonvulsant Effects of Dingxian Pill in Pentylenetetrazol-Kindled Rats. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2019; 2019:4534167. [PMID: 31011358 PMCID: PMC6442303 DOI: 10.1155/2019/4534167] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 02/24/2019] [Indexed: 12/24/2022]
Abstract
Dingxian pill has been used as an antiepilepsy agent in China from ancient to modern times, of which the concrete pharmacological characterization and the underlying molecular mechanism remain unclear. The present study was undertaken to investigate them by animal behavior, electroencephalogram (EEG), Morris water maze, immunohistochemistry, transcriptomics, and real-time PCR. In our results, the treatment of Dingxian pill dose-dependently inhibited PTZ-induced seizure-like behavior and reduced the seizure grades, LFP power spectral density, and brain wave of the epileptiform EEG component induced by PTZ. In Morris water maze tests, the learning and memory ability of kindled epileptic rats could be attenuated more efficiently by Dingxian pill. For the immediate early gene c-fos, the expression was reduced after Dingxian pill treatment, and the difference was significant between the treatment and the model group. Through the transcriptome analysis of the gene expression in hippocampus, Egr3, Nrg, Arc, and Ptgs2, closely related to epilepsy, had been proved to be downregulated by application of Dingxian pill. All of the results not only highlight the antiepileptic effects of Dingxian pill and its molecular mechanism, but also provide a modern validity theory for the clinical application of traditional Chinese medicine (TCM).
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36
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Worts PR, Burkhart SO, Kim JS. A Physiologically Based Approach to Prescribing Exercise Following a Sport-Related Concussion. Sports Med 2019; 49:683-706. [DOI: 10.1007/s40279-019-01065-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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37
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Ekstrand C, Falkenö U, Kallings P, Tvedten H, Lilliehöök I. Plasma Dexamethasone Concentration in Relation to Glucose Response in the Horse. J Equine Vet Sci 2019. [DOI: 10.1016/j.jevs.2018.11.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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38
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SANTOS MPPD, SPINELI H, BASTOS-SILVA VJ, LEARSI SK, ARAUJO GGD. Ingestion of a drink containing carbohydrate increases the number of bench press repetitions. REV NUTR 2019. [DOI: 10.1590/1678-9865201932e180056] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
ABSTRACT Objective The aim of this study was to analyze the effects of carbohydrate ingestion prior to exercise on the number of bench press repetitions. Methods Eight male physically active (21.3±2.7 years, 176±5cm, 73.12±6.12kg), with a minimum experience of at least one year exercising regularly, visited the laboratory at three moments. During the first visit, candidates went through their anthropometric evaluation and the application of their maximum number of bench press repetitions. The experimental tests were performed during their second and third visits in a crossover and blind study. The participants performed the maximum number of repetitions with an intensity of 70% of their maximum repetition strength. One hour before the experimental trials, participants randomly ingested a solution containing either carbohydrate or a placebo. Results The ingestion of carbohydrate increases muscle resistance in relation to placebo (p=0.014; effect size=0.71). This is evidenced by the increase in the number of repetitions (12.9±2.4 and 11.3±1.9, respectively). The individual’s perception of effort is higher in the carbohydrate group than in the placebo group after exhaustion (4±0.93 and 3.1±0.64, respectively, p=0.006, effect size=0.89). Conclusion It is concluded that a previous intake of carbohydrate is useful in improving performance in resistance exercises, providing an increase in the individual’s perception of effort.
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Baldassarre R, Sacchetti M, Patrizio F, Nicolò A, Scotto di Palumbo A, Bonifazi M, Piacentini MF. Carbohydrate Supplementation Does Not Improve 10 km Swimming Intermittent Training. Sports (Basel) 2018; 6:sports6040147. [PMID: 30441819 PMCID: PMC6316724 DOI: 10.3390/sports6040147] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 11/06/2018] [Accepted: 11/07/2018] [Indexed: 11/30/2022] Open
Abstract
The aim of the present study was to test the effectiveness of carbohydrate (CHO) feeding supplemented every 2.5-km, as in official races, on the performance, rating of perceived exertion (RPE), and glycaemia during a 10-km intermittent training workout in elite open-water swimmers. A randomized crossover design was used. Participants completed two 10-km intermittent training sessions (20 × 500-m). The relative velocity was expressed in percentage of a single 500-m. Glycaemia was monitored by continuous glucose monitoring. Participants had to ingest either 1 L of tap water (WAT; 0.50 L·h−1) or 120 g of CHO in the form of 8% solution (60 g·h−1). The 15-point RPE scale was used during the trials. A two-way ANOVA for repeated measures was performed (p < 0.05). The relative velocity of each 500-m was not significantly different between the two trials. No significant differences emerged in the relative velocity of the last 500-m between trials. Average RPE was not statistically different between the two trials (11 ± 3 in WAT and 12 ± 3 in CHO). In the last 500-m, glycaemia was significantly higher in the CHO trial (5.92 ± 0.47 mmol·L−1 in CHO; 5.61 ± 0.61 mmol·L−1 in WAT). CHO ingestion did not improve performance or affect RPE during a 10-km intermittent training in elite open-water swimmers.
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Affiliation(s)
- Roberto Baldassarre
- Department of Movement, Human and Health Sciences, University of Rome Foro Italico, 00135 Rome, Italy.
| | - Massimo Sacchetti
- Department of Movement, Human and Health Sciences, University of Rome Foro Italico, 00135 Rome, Italy.
| | - Federica Patrizio
- Department of Movement, Human and Health Sciences, University of Rome Foro Italico, 00135 Rome, Italy.
| | - Andrea Nicolò
- Department of Movement, Human and Health Sciences, University of Rome Foro Italico, 00135 Rome, Italy.
| | | | - Marco Bonifazi
- Department of Medical, Surgical and Neuro Sciences, University of Siena, 53100 Siena, Italy.
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Paris HL, Fulton TJ, Chapman RF, Fly AD, Koceja DM, Mickleborough TD. Effect of carbohydrate ingestion on central fatigue during prolonged running exercise in moderate hypoxia. J Appl Physiol (1985) 2018; 126:141-151. [PMID: 30412032 DOI: 10.1152/japplphysiol.00684.2018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To determine whether acute exposure to moderate hypoxia alters central and peripheral fatigue and to test whether carbohydrate ingestion impacts fatigue characteristics, 12 trained runners completed three running trials lasting 1 h each at 65% of normoxic maximum oxygen uptake. The first trial was performed in normoxia [inspired O2 fraction ( FiO2 ) = 0.21], and the last two trials were completed in hypoxia ( FiO2 = 0.15). Participants ingested a placebo drink in normoxia (NORM-PLA), a placebo drink in hypoxia (HYP-PLA), or a carbohydrate solution in hypoxia (HYP-CHO). HYP conditions were randomized. Peripheral [change in potentiated quadriceps twitch force (ΔQtw,pot)] and central [change in voluntary activation (ΔVA)] fatigue were assessed via preexercise-to-postexercise changes in magnetically evoked quadriceps twitch. In HYP, blood was drawn to determine the ratio of free-tryptophan (f-TRP) to branched-chain amino acids (BCAA). After exercise, peripheral fatigue was reduced to a similar degree in normoxia and hypoxia (ΔQtw,pot = -4.5 ± 1.3% and -4.0 ± 1.5% in NORM-PLA and HYP-PLA, respectively; P = 0.61). Central fatigue was present after normoxic and hypoxic exercise but to a greater degree in HYP-PLA compared with NORM-PLA (ΔVA: -4.7 ± 0.9% vs. -1.9 ± 0.7%; P < 0.01). Carbohydrate ingestion did not influence central fatigue (ΔVA in HYP-CHO: -5.7 ± 1.2%; P = 0.51 vs. HYP-PLA). After exercise, no differences were observed in the ratio of f-TRP to BCAA between HYP-PLA and HYP-CHO ( P = 0.67). Central fatigue increased during prolonged running exercise in moderate hypoxia although the ratio of f-TRP to BCAA remained unchanged. Ingesting carbohydrates while running in hypoxia did not influence fatigue development. NEW & NOTEWORTHY Hypoxic exposure influences the origin of exercise-induced fatigue and the rate of fatigue development depending on the severity of hypoxia. Our data suggest that moderate hypoxia increases central, but not peripheral, fatigue in trained runners exercising at 65% of normoxic maximum oxygen uptake. The increase in central fatigue was unaffected by carbohydrate intake and occurred although the ratio of free tryptophan to branched-chain amino acids remained unchanged.
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Affiliation(s)
- Hunter L Paris
- Department of Kinesiology, School of Public Health-Bloomington, Indiana University , Bloomington, Indiana
| | - Timothy J Fulton
- Department of Kinesiology, School of Public Health-Bloomington, Indiana University , Bloomington, Indiana
| | - Robert F Chapman
- Department of Kinesiology, School of Public Health-Bloomington, Indiana University , Bloomington, Indiana
| | - Alyce D Fly
- Department of Applied Health Science, School of Public Health-Bloomington, Indiana University , Bloomington, Indiana
| | - David M Koceja
- Department of Kinesiology, School of Public Health-Bloomington, Indiana University , Bloomington, Indiana
| | - Timothy D Mickleborough
- Department of Kinesiology, School of Public Health-Bloomington, Indiana University , Bloomington, Indiana
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Khong TK, Selvanayagam VS, Hamzah SH, Yusof A. Effect of quantity and quality of pre-exercise carbohydrate meals on central fatigue. J Appl Physiol (1985) 2018; 125:1021-1029. [PMID: 29975601 DOI: 10.1152/japplphysiol.00221.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Both the quantity and quality of pre-exercise carbohydrate (CHO) meals have been shown to improve endurance performance. However, their role in attenuating central fatigue (CF) is inconclusive. The use of neurophysiological techniques, such as voluntary activation (VA) and the central activation ratio (CAR), alongside maximum voluntary contraction (MVC) and sustained MVC (sMVC) can provide information on CF. Hence, the objective of this study was to investigate the effects of isocaloric pre-exercise meals: 1) a high versus low quantity of CHO and 2) a high quantity of CHO with a high versus low glycemic index (GI) on MVC, VA, and CAR following a 90-min run. The high and low quantity of CHO was 1.5 and 0.8 g/kg body wt, respectively, and high and low GI was ~75 and ~40, respectively. Blood insulin, serotonin, tryptophan, and gaseous exchange were also measured. High CHO preserved sMVC, VA, CAR, and serotonin postrunning with greater CHO oxidation and insulin response, whereas in low CHO, greater reductions in sMVC, VA, and CAR were accompanied by higher serotonin and fat oxidation with lower insulin response. These observations indicate central involvements. Meanwhile, high GI CHO better preserved force (sMVC), CAR, and tryptophan with greater CHO oxidation and insulin response compared with low GI. The findings of this study suggest that pre-exercise meals with varying quantity and quality of CHO can have an effect on CF, where greater CHO oxidation and insulin response found in both high CHO and high GI lead to attenuation of CF. NEW & NOTEWORTHY This paper examined the effects of carbohydrate interventions (high and low: quantity and quality wise) on central activity during prolonged exercise using mainly neurophysiological techniques along with gaseous exchange and blood insulin, serotonin, and tryptophan data.
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Affiliation(s)
- Teng Keen Khong
- Centre of Sports and Exercise Sciences, University of Malaya , Kuala Lumpur , Malaysia.,Department of Sports Sciences, Faculty of Applied Sciences, Tunku Abdul Rahman University College , Kuala Lumpur , Malaysia
| | - Victor S Selvanayagam
- Centre of Sports and Exercise Sciences, University of Malaya , Kuala Lumpur , Malaysia
| | - Sareena Hanim Hamzah
- Centre of Sports and Exercise Sciences, University of Malaya , Kuala Lumpur , Malaysia
| | - Ashril Yusof
- Centre of Sports and Exercise Sciences, University of Malaya , Kuala Lumpur , Malaysia
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Manio MCC, Matsumura S, Masuda D, Inoue K. CD36 is essential for endurance improvement, changes in whole-body metabolism, and efficient PPAR-related transcriptional responses in the muscle with exercise training. Physiol Rep 2018; 5:e13282. [PMID: 28526781 PMCID: PMC5449563 DOI: 10.14814/phy2.13282] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 04/18/2017] [Indexed: 11/24/2022] Open
Abstract
Although circulating fatty acids are utilized as energy substrates, they also function as ligands to the peroxisome‐proliferator activated receptors (PPARs), a family of fatty acid sensing transcription factors. Exercise training leads to various adaptations in the muscle such as elevation of glycogen content, mitochondrial number as well as upregulation of fatty acid uptake and utilization through downstream transcriptional adaptations. In line with this, CD36 has been shown to be critical in controlling fatty acid uptake and consequently, fatty acid oxidation. We show that exercise training could not ameliorate impaired endurance performance in CD36 KO mice despite intact adaptations in muscle glycogen storage and mitochondrial function. Changes in whole‐body metabolism at rest and during exercise were also suppressed in these animals. Furthermore, there was inefficient upregulation of PPAR and PPAR‐related exercise‐responsive genes with chronic training in CD36 KO mice despite normal upregulation of Pgc1a and mitochondrial genes. Our findings supplement previous observations and emphasize the importance of CD36 in endurance performance, energy production and efficient downstream transcriptional regulation by PPARs.
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Affiliation(s)
- Mark Christian C Manio
- Laboratory of Nutrition Chemistry, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Shigenobu Matsumura
- Laboratory of Nutrition Chemistry, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Daisaku Masuda
- Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Kazuo Inoue
- Laboratory of Nutrition Chemistry, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
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Metabolic Responses to Carbohydrate Ingestion during Exercise: Associations between Carbohydrate Dose and Endurance Performance. Nutrients 2018; 10:nu10010037. [PMID: 29301367 PMCID: PMC5793265 DOI: 10.3390/nu10010037] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 12/20/2017] [Accepted: 12/25/2017] [Indexed: 11/17/2022] Open
Abstract
Carbohydrate (CHO) ingestion during exercise lasting less than three hours improves endurance exercise performance but there is still debate about the optimal dose. We utilised stable isotopes and blood metabolite profiles to further examine metabolic responses to CHO (glucose only) ingestion in the 20–64 g·h−1 range, and to determine the association with performance outcome. In a double-blind, randomized cross-over design, male cyclists (n = 20, mean ± SD, age 34 ± 10 years, mass 75.8 ± 9 kg, peak power output 394 ± 36 W, VO2max 62 ± 9 mL·kg−1·min−1) completed four main experimental trials. Each trial involved a two-hour constant load ride (185 ± 25 W) followed by a time trial, where one of three CHO beverages, or a control (water), were administered every 15 min, providing 0, 20, 39 or 64 g CHO·h−1. Dual glucose tracer techniques, indirect calorimetry and blood analyses were used to determine glucose kinetics, exogenous CHO oxidation (EXO), endogenous CHO and fat oxidation; and metabolite responses. Regression analysis revealed that total exogenous CHO oxidised in the second hour of exercise, and suppression of serum NEFA concentration provided the best prediction model of performance outcome. However, the model could only explain ~19% of the variance in performance outcome. The present data demonstrate that consuming ~40 g·h−1 of CHO appears to be the minimum ingestion rate required to induce metabolic effects that are sufficient to impact upon performance outcome. These data highlight a lack of performance benefit and few changes in metabolic outcomes beyond an ingestion rate of 39 g·h−1. Further work is required to explore dose-response effects of CHO feeding and associations between multiple metabolic parameters and subsequent performance outcome.
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Gui Z, Sun F, Si G, Chen Y. Effect of protein and carbohydrate solutions on running performance and cognitive function in female recreational runners. PLoS One 2017; 12:e0185982. [PMID: 29023535 PMCID: PMC5638311 DOI: 10.1371/journal.pone.0185982] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Accepted: 09/22/2017] [Indexed: 11/24/2022] Open
Abstract
This study compared the effects of a carbohydrate–electrolyte–protein solution (CEPS, 2% protein plus 4% carbohydrate), carbohydrate–electrolyte solution (CES, 6% carbohydrate), and noncaloric sweetened placebo (PLA) on both 21-km running performance and cognitive function. Eleven female recreational endurance runners performed a 21-km time-trial running on three occasions, separated by at least 28 days. In a randomized cross-over design, they ingested CEPS, CES, or PLA at a rate of 150 mL every 2.5 km with no time feedback. A cognitive function test was performed before and after the run. Participants ingested approximately 24 g/h carbohydrate plus 12 g/h protein in CEPS trial, and 36 g/h carbohydrate in CES trial during each 21-km trial. Time to complete the time-trial was slightly shorter (P < 0.05) during CES (129.6 ± 8.8 min) than PLA (134.6 ± 11.5 min), with no differences between CEPS and the other two trials. The CEPS trial showed higher composite of visual motor speed than the PLA trial (P < 0.05). In conclusion, CES feedings might improve 21-km time-trial performance in female recreational runners compared with a PLA. However, adding protein to the CES provided no additional time-trial performance benefit. CEPS feeding during prolonged exercise could benefit visual motor speed compared to PLA alone, but no differences in the performance of the other cognitive function tests were found.
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Affiliation(s)
- Zhaohuan Gui
- Department of Maternal and Child Health, School of Public Health, Sun Yat-Sen University, Guangzhou, Guangdong, China
- Department of Health and Physical Education, The Education University of Hong Kong, Tai Po, Hong Kong
| | - Fenghua Sun
- Department of Health and Physical Education, The Education University of Hong Kong, Tai Po, Hong Kong
- * E-mail: (FS); (YC)
| | - Gangyan Si
- Department of Health and Physical Education, The Education University of Hong Kong, Tai Po, Hong Kong
| | - Yajun Chen
- Department of Maternal and Child Health, School of Public Health, Sun Yat-Sen University, Guangzhou, Guangdong, China
- * E-mail: (FS); (YC)
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Abstract
Despite flourishing interest in the topic of fatigue-as indicated by the many presentations on fatigue at the 2015 Annual Meeting of the American College of Sports Medicine-surprisingly little is known about its effect on human performance. There are two main reasons for this dilemma: 1) the inability of current terminology to accommodate the scope of the conditions ascribed to fatigue, and 2) a paucity of validated experimental models. In contrast to current practice, a case is made for a unified definition of fatigue to facilitate its management in health and disease. On the basis of the classic two-domain concept of Mosso, fatigue is defined as a disabling symptom in which physical and cognitive function is limited by interactions between performance fatigability and perceived fatigability. As a symptom, fatigue can only be measured by self-report, quantified as either a trait characteristic or a state variable. One consequence of such a definition is that the word fatigue should not be preceded by an adjective (e.g., central, mental, muscle, peripheral, and supraspinal) to suggest the locus of the changes responsible for an observed level of fatigue. Rather, mechanistic studies should be performed with validated experimental models to identify the changes responsible for the reported fatigue. As indicated by three examples (walking endurance in old adults, time trials by endurance athletes, and fatigue in persons with multiple sclerosis) discussed in the review, however, it has proven challenging to develop valid experimental models of fatigue. The proposed framework provides a foundation to address the many gaps in knowledge of how laboratory measures of fatigue and fatigability affect real-world performance.
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Affiliation(s)
- Roger M Enoka
- 1Department of Integrative Physiology, University of Colorado, Boulder, CO; and 2Laboratory of Applied Biology and Neurophysiology, ULB Neuroscience Institute, Université Libre de Bruxelles (ULB), Bruxelles, BELGIUM
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Geng P, Siu KC, Wang Z, Wu JY. Antifatigue Functions and Mechanisms of Edible and Medicinal Mushrooms. BIOMED RESEARCH INTERNATIONAL 2017; 2017:9648496. [PMID: 28890898 PMCID: PMC5584359 DOI: 10.1155/2017/9648496] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 07/16/2017] [Indexed: 12/14/2022]
Abstract
Fatigue is the symptom of tiredness caused by physical and/or psychological stresses. As fatigue is becoming a serious problem in the modern society affecting human health, work efficiency, and quality of life, effective antifatigue remedies other than pharmacological drugs or therapies are highly needed. Mushrooms have been widely used as health foods, because of their various bioactive constituents such as polysaccharides, proteins, vitamins, minerals, and dietary fiber. This paper reviews the major findings from previous studies on the antifatigue effects, the active components of mushrooms, and the possible mechanisms. Many studies have demonstrated the antifatigue effects of edible and medicinal mushrooms. These mushrooms probably mitigate human fatigue through effects on the functional systems, including the muscular, cardiovascular, hormone, and immune system. The bioactive constituents that contribute to the antifatigue effects of mushrooms may include polysaccharides, peptides, nucleosides, phenolic compounds, and triterpenoids. Further research is still needed to identify the active ingredients and to investigate their mechanism of action on the antifatigue effects. Since most previous studies have been carried out in animal models, more human trials should be performed to verify the antifatigue function of edible and medicinal mushrooms.
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Affiliation(s)
- Ping Geng
- Department of Applied Biology & Chemical Technology, State Key Laboratory of Chinese Medicine and Molecular Pharmacology in Shenzhen, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Ka-Chai Siu
- Department of Applied Biology & Chemical Technology, State Key Laboratory of Chinese Medicine and Molecular Pharmacology in Shenzhen, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Zhaomei Wang
- School of Food Science & Engineering, South China University of Technology, Guangzhou 510640, China
| | - Jian-Yong Wu
- Department of Applied Biology & Chemical Technology, State Key Laboratory of Chinese Medicine and Molecular Pharmacology in Shenzhen, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
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Winwood-Smith HS, Franklin CE, White CR. Low-carbohydrate diet induces metabolic depression: a possible mechanism to conserve glycogen. Am J Physiol Regul Integr Comp Physiol 2017; 313:R347-R356. [PMID: 28701319 DOI: 10.1152/ajpregu.00067.2017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 07/05/2017] [Accepted: 07/05/2017] [Indexed: 01/14/2023]
Abstract
Long-term studies have found that low-carbohydrate diets are more effective for weight loss than calorie-restricted diets in the short term but equally or only marginally more effective in the long term. Low-carbohydrate diets have been linked to reduced glycogen stores and increased feelings of fatigue. We propose that reduced physical activity in response to lowered glycogen explains the diminishing weight loss advantage of low-carbohydrate compared with low-calorie diets over longer time periods. We explored this possibility by feeding adult Drosophila melanogaster a standard or a low-carbohydrate diet for 9 days and measured changes in metabolic rate, glycogen stores, activity, and body mass. We hypothesized that a low-carbohydrate diet would cause a reduction in glycogen stores, which recover over time, a reduction in physical activity, and an increase in resting metabolic rate. The low-carbohydrate diet reduced glycogen stores, which recovered over time. Activity was unaffected by diet, but metabolic rate was reduced, in the low-carbohydrate group. We conclude that metabolic depression could explain the decreased effectiveness of low-carbohydrate diets over time and recommend further investigation of long-term metabolic effects of dietary interventions and a greater focus on physiological plasticity within the study of human nutrition.
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Affiliation(s)
- Hugh S Winwood-Smith
- School of Biological Sciences, University of Queensland, Brisbane, Queensland, Australia; and
| | - Craig E Franklin
- School of Biological Sciences, University of Queensland, Brisbane, Queensland, Australia; and
| | - Craig R White
- Centre for Geometric Biology, School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
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Effects of Three Commercially Available Sports Drinks on Substrate Metabolism and Subsequent Endurance Performance in a Postprandial State. Nutrients 2017; 9:nu9040377. [PMID: 28417910 PMCID: PMC5409716 DOI: 10.3390/nu9040377] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 04/03/2017] [Accepted: 04/06/2017] [Indexed: 01/19/2023] Open
Abstract
Purpose: To examine the effects of commercially available sports beverages with various components on substrate metabolism and subsequent performance. Methods: Two studies were conducted in a double-blinded, counterbalanced manner. Study I was designed to determine the glycemic index, while study II determined the utilization of substrates and subsequent exercise performance. Ten healthy male participants (age 21.70 ± 2.41 years, height 176.60 ± 5.23 cm, weight 66.58 ± 5.38 kg, V̇O2max 48.1 ± 8.4 mL/kg/min) participated in both study I and study II. Three types of commercially available sports beverage powders were used. The powders consisted primarily of oligosaccharides (low molecular weight carbohydrates, L-CHO), hydrolyzed starch (high molecular weight CHO, H-CHO), and whey protein powder with carbohydrate (CHO-PRO). They were dissolved in purified water with identical CHO concentration of 8% (w/v). In study I, each participant underwent two oral glucose tolerance tests (OGTT) and one glycemic response test for each sports drink. In study II, participants cycled for 60 min at 70% V̇O2max, one hour after consuming a standardized breakfast. One of four prescribed beverages (L-CHO, H-CHO, CHO-PRO, and Placebo control, PLA) was served at 0, 15, 30, 45 min during the exercise. Six hours after the first exercise session, participants came back for a “time to exhaustion test” (TTE). Blood samples were drawn at 0, 30, and 60 min in the first exercise session, while arterial blood gas analysis was conducted at 0, 30, and 60 min in both sessions. Subjective feelings (rating of perceived exertion and abdominal discomfort) were also evaluated every 30 min during exercise. Results: Compared to the reference standardized glucose solution, the glycemic index of the L-CHO beverage was 117.70 ± 14.25, while H-CHO was 105.50 ± 12.82, and CHO-PRO was 67.23 ± 5.88. During the exercise test, the insulin level at 30 and 60 min was significantly lower than baseline following the treatment of L-CHO, H-CHO, and PLA (p < 0.05). The CHO oxidation rate at 60 min in the first exercise session was significantly higher than that at 60 min in the second exercise session following the L-CHO treatment (p < 0.05). Time to exhaustion was not significantly different (p > 0.05). Conclusion: The CHO sports beverage with additional PRO maintains insulin production during endurance cycling at 70% V̇O2max in the postprandial state. L-CHO sports beverage suppresses fat utilization during the subsequent exercise performance test. The subsequent exercise performance (as evaluated by TTE) was not influenced by the type of CHO or the addition of PRO in the commercially available sports beverages used in the present study.
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Rosset R, Lecoultre V, Egli L, Cros J, Dokumaci AS, Zwygart K, Boesch C, Kreis R, Schneiter P, Tappy L. Postexercise repletion of muscle energy stores with fructose or glucose in mixed meals. Am J Clin Nutr 2017; 105:609-617. [PMID: 28100512 DOI: 10.3945/ajcn.116.138214] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 12/12/2016] [Indexed: 11/14/2022] Open
Abstract
Background: Postexercise nutrition is paramount to the restoration of muscle energy stores by providing carbohydrate and fat as precursors of glycogen and intramyocellular lipid (IMCL) synthesis. Compared with glucose, fructose ingestion results in lower postprandial glucose and higher lactate and triglyceride concentrations. We hypothesized that these differences in substrate concentration would be associated with a different partition of energy stored as IMCLs or glycogen postexercise.Objective: The purpose of this study was to compare the effect of isocaloric liquid mixed meals containing fat, protein, and either fructose or glucose on the repletion of muscle energy stores over 24 h after a strenuous exercise session.Design: Eight male endurance athletes (mean ± SEM age: 29 ± 2 y; peak oxygen consumption: 66.8 ± 1.3 mL · kg-1 · min-1) were studied twice. On each occasion, muscle energy stores were first lowered by a combination of a 3-d controlled diet and prolonged exercise. After assessment of glycogen and IMCL concentrations in vastus muscles, subjects rested for 24 h and ingested mixed meals providing fat and protein together with 4.4 g/kg fructose (the fructose condition; FRU) or glucose (the glucose condition; GLU). Postprandial metabolism was assessed over 6 h, and glycogen and IMCL concentrations were measured again after 24 h. Finally, energy metabolism was evaluated during a subsequent exercise session.Results: FRU and GLU resulted in similar IMCL [+2.4 ± 0.4 compared with +2.0 ± 0.6 mmol · kg-1 wet weight · d-1; time × condition (mixed-model analysis): P = 0.45] and muscle glycogen (+10.9 ± 0.9 compared with +12.3 ± 1.9 mmol · kg-1 wet weight · d-1; time × condition: P = 0.45) repletion. Fructose consumption in FRU increased postprandial net carbohydrate oxidation and decreased net carbohydrate storage (estimating total, muscle, and liver glycogen synthesis) compared with GLU (+117 ± 9 compared with +135 ± 9 g/6 h, respectively; P < 0.01). Compared with GLU, FRU also resulted in lower plasma glucose concentrations and decreased exercise performance the next day.Conclusions: Mixed meals containing fat, protein, and either fructose or glucose elicit similar repletion of IMCLs and muscle glycogen. Under such conditions, fructose lowers whole-body glycogen synthesis and impairs subsequent exercise performance, presumably because of lower hepatic glycogen stores. This trial was registered at clinicaltrials.gov as NCT01866215.
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Affiliation(s)
- Robin Rosset
- Department of Physiology, University of Lausanne, Lausanne, Switzerland; and
| | - Virgile Lecoultre
- Department of Physiology, University of Lausanne, Lausanne, Switzerland; and
| | - Léonie Egli
- Department of Physiology, University of Lausanne, Lausanne, Switzerland; and
| | - Jérémy Cros
- Department of Physiology, University of Lausanne, Lausanne, Switzerland; and
| | - Ayse Sila Dokumaci
- Department of Clinical Research and Radiology, University of Bern, Bern, Switzerland
| | - Karin Zwygart
- Department of Clinical Research and Radiology, University of Bern, Bern, Switzerland
| | - Chris Boesch
- Department of Clinical Research and Radiology, University of Bern, Bern, Switzerland
| | - Roland Kreis
- Department of Clinical Research and Radiology, University of Bern, Bern, Switzerland
| | - Philippe Schneiter
- Department of Physiology, University of Lausanne, Lausanne, Switzerland; and
| | - Luc Tappy
- Department of Physiology, University of Lausanne, Lausanne, Switzerland; and
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