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Quinn CP, McDougall RM, Aboodarda SJ, Murias JM, MacInnis MJ. Effects of carbohydrate availability on cycling endurance at the maximal lactate steady state. Am J Physiol Regul Integr Comp Physiol 2024; 326:R266-R275. [PMID: 38223937 DOI: 10.1152/ajpregu.00178.2023] [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: 07/18/2023] [Revised: 12/20/2023] [Accepted: 01/08/2024] [Indexed: 01/16/2024]
Abstract
The impacts of carbohydrate (CHO) availability on time to task failure (TTF) and physiological responses to exercise at the maximal lactate steady state (MLSS) have not been studied. Ten participants (3 females, 7 males) completed this double-blinded, placebo-controlled study that involved a ramp incremental test, MLSS determination, and four TTF trials at MLSS, all performed on a cycle ergometer. With the use of a combination of nutritional (CHO, 7 g/kg, and placebo, PLA, 0 g/kg drinks) and exercise interventions [no exercise (REST) and glycogen-reducing exercise (EX)], the four conditions were expected to differ in preexercise CHO availability (RESTCHO > RESTPLA > EXCHO > EXPLA). TTF at MLSS was not improved by CHO loading, as RESTCHO (57.1 [16.6] min) and RESTPLA (57.1 [15.6] min) were not different (P = 1.00); however, TTF was ∼50% shorter in EX conditions compared with REST conditions on average (P < 0.05), with EXCHO (39.1 [9.2] min) ∼90% longer than EXPLA (20.6 [6.9] min; P < 0.001). There were effects of condition for all perceptual and cardiometabolic variables when compared at isotime (P < 0.05) and task failure (TF; P < 0.05), except for ventilation, perceptual responses, and neuromuscular function measures, which were not different at TF (P > 0.05). Blood lactate concentration was stable in all conditions for participants who completed 30 min of exercise. These findings indicate that TTF at MLSS is not enhanced by preexercise CHO supplementation, but recent intense exercise decreases TTF at MLSS even with CHO supplementation. Extreme fluctuations in diet and strenuous exercise that reduce CHO availability should be avoided before MLSS determination.NEW & NOTEWORTHY Carbohydrate (CHO) loading did not increase participants' ability to cycle at their maximal lactate steady state (MLSS); however, performing a glycogen depletion task the evening before cycling at MLSS reduced the time to task failure, even when paired with a high dose of CHO. These diet and exercise interventions influenced blood lactate concentration ([BLa]) but not the stability of [BLa]. Activities that reduce CHO availability should be avoided before MLSS determination.
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Affiliation(s)
- Colton P Quinn
- Faculty of Kinesiology, Human Performance Lab, University of Calgary, Alberta, Canada
| | - Rachel M McDougall
- Faculty of Kinesiology, Human Performance Lab, University of Calgary, Alberta, Canada
| | - Saied Jalal Aboodarda
- Faculty of Kinesiology, Human Performance Lab, University of Calgary, Alberta, Canada
| | - Juan M Murias
- Faculty of Kinesiology, Human Performance Lab, University of Calgary, Alberta, Canada
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
| | - Martin J MacInnis
- Faculty of Kinesiology, Human Performance Lab, University of Calgary, Alberta, Canada
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Margolis LM, Marlatt KL, Berryman CE, Howard EE, Murphy NE, Carrigan CT, Harris MN, Beyl RA, Ravussin E, Pasiakos SM, Rood JC. Metabolic Adaptations and Substrate Oxidation are Unaffected by Exogenous Testosterone Administration during Energy Deficit in Men. Med Sci Sports Exerc 2023; 55:661-669. [PMID: 36563086 DOI: 10.1249/mss.0000000000003089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
INTRODUCTION/PURPOSE The effects of testosterone on energy and substrate metabolism during energy deficit are unknown. The objective of this study was to determine the effects of weekly testosterone enanthate (TEST; 200 mg·wk -1 ) injections on energy expenditure, energy substrate oxidation, and related gene expression during 28 d of energy deficit compared with placebo (PLA). METHODS After a 14-d energy balance phase, healthy men were randomly assigned to TEST ( n = 24) or PLA ( n = 26) for a 28-d controlled diet- and exercise-induced energy deficit (55% below total energy needs by reducing energy intake and increasing physical activity). Whole-room indirect calorimetry and 24-h urine collections were used to measure energy expenditure and energy substrate oxidation during balance and deficit. Transcriptional regulation of energy and substrate metabolism was assessed using quantitative reverse transcription-polymerase chain reaction from rested/fasted muscle biopsy samples collected during balance and deficit. RESULTS Per protocol design, 24-h energy expenditure increased ( P < 0.05) and energy intake decreased ( P < 0.05) in TEST and PLA during deficit compared with balance. Carbohydrate oxidation decreased ( P < 0.05), whereas protein and fat oxidation increased ( P < 0.05) in TEST and PLA during deficit compared with balance. Change (∆; deficit minus balance) in 24-h energy expenditure was associated with ∆activity factor ( r = 0.595), but not ∆fat-free mass ( r = 0.147). Energy sensing (PRKAB1 and TP53), mitochondria (TFAM and COXIV), fatty acid metabolism (CD36/FAT, FABP, CPT1b, and ACOX1) and storage (FASN), and amino acid metabolism (BCAT2 and BCKHDA) genes were increased ( P < 0.05) during deficit compared with balance, independent of treatment. CONCLUSIONS These data demonstrate that increased physical activity and not exogenous testosterone administration is the primary determinate of whole-body and skeletal muscle metabolic adaptations during diet- and exercise-induced energy deficit.
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Affiliation(s)
- Lee M Margolis
- Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, MA
| | | | | | - Emily E Howard
- Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, MA
| | - Nancy E Murphy
- Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, MA
| | - Christopher T Carrigan
- Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, MA
| | | | - Robbie A Beyl
- Pennington Biomedical Research Center, Baton Rouge, LA
| | - Eric Ravussin
- Pennington Biomedical Research Center, Baton Rouge, LA
| | - Stefan M Pasiakos
- Military Performance Division, US Army Research Institute of Environmental Medicine, Natick, MA
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Nielsen J. An experiment of nature links muscle glycogen unavailability with very high fat oxidation rates despite low aerobic fitness. J Physiol 2023; 601:389-390. [PMID: 36601698 DOI: 10.1113/jp284098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 01/04/2023] [Indexed: 01/06/2023] Open
Affiliation(s)
- Joachim Nielsen
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
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Factors Influencing Substrate Oxidation During Submaximal Cycling: A Modelling Analysis. Sports Med 2022; 52:2775-2795. [PMID: 35829994 PMCID: PMC9585001 DOI: 10.1007/s40279-022-01727-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/20/2022] [Indexed: 02/01/2023]
Abstract
BACKGROUND Multiple factors influence substrate oxidation during exercise including exercise duration and intensity, sex, and dietary intake before and during exercise. However, the relative influence and interaction between these factors is unclear. OBJECTIVES Our aim was to investigate factors influencing the respiratory exchange ratio (RER) during continuous exercise and formulate multivariable regression models to determine which factors best explain RER during exercise, as well as their relative influence. METHODS Data were extracted from 434 studies reporting RER during continuous cycling exercise. General linear mixed-effect models were used to determine relationships between RER and factors purported to influence RER (e.g., exercise duration and intensity, muscle glycogen, dietary intake, age, and sex), and to examine which factors influenced RER, with standardized coefficients used to assess their relative influence. RESULTS The RER decreases with exercise duration, dietary fat intake, age, VO2max, and percentage of type I muscle fibers, and increases with dietary carbohydrate intake, exercise intensity, male sex, and carbohydrate intake before and during exercise. The modelling could explain up to 59% of the variation in RER, and a model using exclusively easily modified factors (exercise duration and intensity, and dietary intake before and during exercise) could only explain 36% of the variation in RER. Variables with the largest effect on RER were sex, dietary intake, and exercise duration. Among the diet-related factors, daily fat and carbohydrate intake have a larger influence than carbohydrate ingestion during exercise. CONCLUSION Variability in RER during exercise cannot be fully accounted for by models incorporating a range of participant, diet, exercise, and physiological characteristics. To better understand what influences substrate oxidation during exercise further research is required on older subjects and females, and on other factors that could explain additional variability in RER.
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Margolis LM, Karl JP, Wilson MA, Coleman JL, Whitney CC, Pasiakos SM. Serum Branched-Chain Amino Acid Metabolites Increase in Males When Aerobic Exercise Is Initiated with Low Muscle Glycogen. Metabolites 2021; 11:metabo11120828. [PMID: 34940586 PMCID: PMC8708125 DOI: 10.3390/metabo11120828] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Revised: 11/21/2021] [Accepted: 11/29/2021] [Indexed: 12/03/2022] Open
Abstract
This study used global metabolomics to identify metabolic factors that might contribute to muscle anabolic resistance, which develops when aerobic exercise is initiated with low muscle glycogen using global metabolomics. Eleven men completed this randomized, crossover study, completing two cycle ergometry glycogen depletion trials, followed by 24 h of isocaloric refeeding to elicit low (LOW; 1.5 g/kg carbohydrate, 3.0 g/kg fat) or adequate (AD; 6.0 g/kg carbohydrate 1.0 g/kg fat) glycogen. Participants then performed 80 min of cycling (64 ± 3% VO2 peak) while ingesting 146 g carbohydrate. Serum was collected before glycogen depletion under resting and fasted conditions (BASELINE), and before (PRE) and after (POST) exercise. Changes in metabolite profiles were calculated by subtracting BASELINE from PRE and POST within LOW and AD. There were greater increases (p < 0.05, Q < 0.10) in 64% of branched-chain amino acids (BCAA) metabolites and 69% of acyl-carnitine metabolites in LOW compared to AD. Urea and 3-methylhistidine had greater increases (p < 0.05, Q < 0.10) in LOW compared to AD. Changes in metabolomics profiles indicate a greater reliance on BCAA catabolism for substrate oxidation when exercise is initiated with low glycogen stores. These findings provide a mechanistic explanation for anabolic resistance associated with low muscle glycogen, and suggest that exogenous BCAA requirements to optimize muscle recovery are likely greater than current recommendations.
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Affiliation(s)
- Lee M. Margolis
- U.S. Army Research Institute of Environmental Medicine, Natick, MA 01760, USA; (J.P.K.); (M.A.W.); (J.L.C.); (C.C.W.); (S.M.P.)
- Correspondence: ; Tel.: +508-206-2335
| | - J Philip Karl
- U.S. Army Research Institute of Environmental Medicine, Natick, MA 01760, USA; (J.P.K.); (M.A.W.); (J.L.C.); (C.C.W.); (S.M.P.)
| | - Marques A. Wilson
- U.S. Army Research Institute of Environmental Medicine, Natick, MA 01760, USA; (J.P.K.); (M.A.W.); (J.L.C.); (C.C.W.); (S.M.P.)
| | - Julie L. Coleman
- U.S. Army Research Institute of Environmental Medicine, Natick, MA 01760, USA; (J.P.K.); (M.A.W.); (J.L.C.); (C.C.W.); (S.M.P.)
- Oak Ridge Institute of Science and Education, Oak Ridge, TN 37830, USA
| | - Claire C. Whitney
- U.S. Army Research Institute of Environmental Medicine, Natick, MA 01760, USA; (J.P.K.); (M.A.W.); (J.L.C.); (C.C.W.); (S.M.P.)
| | - Stefan M. Pasiakos
- U.S. Army Research Institute of Environmental Medicine, Natick, MA 01760, USA; (J.P.K.); (M.A.W.); (J.L.C.); (C.C.W.); (S.M.P.)
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Small SD, Margolis LM. Impact of Dietary Carbohydrate Restriction versus Energy Restriction on Exogenous Carbohydrate Oxidation during Aerobic Exercise. Adv Nutr 2021; 13:S2161-8313(22)00076-X. [PMID: 34788795 PMCID: PMC8970824 DOI: 10.1093/advances/nmab124] [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: 02/01/2023] Open
Abstract
Individuals with high physical activity levels, such as athletes and military personnel, are likely to experience periods of low muscle glycogen content. Reductions in glycogen stores are associated with impaired physical performance. Lower glycogen stores in these populations are likely due to sustained aerobic exercise coupled with sub-optimal carbohydrate or energy intake. Consuming exogenous carbohydrate during aerobic exercise may be an effective intervention to sustain physical performance during periods of low glycogen. However, research is limited in the area of carbohydrate recommendations to fuel performance during periods of sub-optimal carbohydrate and energy intake. Additionally, the studies that have investigated the effects of low glycogen stores on exogenous carbohydrate oxidation have yielded conflicting results. Discrepancies between studies may be the result of glycogen stores being lowered by restricting carbohydrate or restricting energy intake. This narrative review discusses the influence of low glycogen status resulting from carbohydrate restriction versus energy restriction on exogenous carbohydrate oxidation and examines the potential mechanism resulting in divergent responses in exogenous carbohydrate oxidation. Results from this review indicate that rates of exogenous carbohydrate oxidation can be maintained when glycogen content is lower following carbohydrate restrictions, but may be reduced following energy restriction. Reductions in exogenous carbohydrate oxidation following energy restriction appear to result from lower insulin sensitivity and glucose uptake. Exogenous carbohydrate may thus be an effective intervention to sustain performance following short-term energy adequate carbohydrate restriction, but may not be an effective ergogenic aid when glycogen stores are low due to energy restriction.
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Affiliation(s)
- Stephanie D Small
- Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, MA, USA,Oak Ridge Institute of Science and Education, Oak Ridge, TN, USA
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Ma X, Chen H, Cao L, Zhao S, Zhao C, Yin S, Hu H. 18β-glycyrrhetinic acid improves high-intensity exercise performance by promoting glucose-dependent energy production and inhibiting oxidative stress in mice. Phytother Res 2021; 35:6932-6943. [PMID: 34709693 DOI: 10.1002/ptr.7310] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 09/10/2021] [Accepted: 09/30/2021] [Indexed: 01/08/2023]
Abstract
It has been shown that 18β-glycyrrhetinic acid (18β-GA), the main bioactive compound of licorice, can modulate oxidative stress and metabolic processes in liver and skin. Given the critical role of oxidative stress and energy metabolism in exercise-induced fatigue, we hypothesized that 18β-GA could exert an ergogenic action by inhibiting excess reactive oxygen species (ROS) induction and promoting energy production in muscles. Mice were gavage-fed with 18β-GA for four consecutive days. Running ability was assessed based on the exhaustive treadmill test with high- and moderate-intensity. Western blot analysis, enzyme-linked immunosorbent assay, and immunofluorescence staining were used to measure the changes of muscle fatigue-related markers, oxidative stress status, and energy metabolism in response to 18β-GA exposure. Treatment with 18β-GA significantly increased the exhaustive running distance (~37%) in the high-intensity exercise, but not in the moderate-intensity exercise. Mechanistically, reduction of oxidative stress and induction of antioxidants (SOD, CAT, and GSH) by 18β-GA were observed. Moreover, 18β-GA treatment caused an improved preservation of muscle glycogen (12%), which was associated with upregulation of glucose transporter 4 (GLUT4) (91%) and increased insulin level (17%). The findings of the present study clearly suggest that 18β-GA holds excellent potential as a novel bioactive agent against high-intensity exercise-induced fatigue.
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Affiliation(s)
- Xuan Ma
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Hui Chen
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Lixing Cao
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Shuang Zhao
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Chong Zhao
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Shutao Yin
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
| | - Hongbo Hu
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
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Margolis LM, Wilson MA, Whitney CC, Carrigan CT, Murphy NE, Hatch-McChesney A, Pasiakos SM. Initiating aerobic exercise with low glycogen content reduces markers of myogenesis but not mTORC1 signaling. J Int Soc Sports Nutr 2021; 18:56. [PMID: 34246303 PMCID: PMC8272266 DOI: 10.1186/s12970-021-00455-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 06/22/2021] [Indexed: 12/29/2022] Open
Abstract
Background The effects of low muscle glycogen on molecular markers of protein synthesis and myogenesis before and during aerobic exercise with carbohydrate ingestion is unclear. The purpose of this study was to determine the effects of initiating aerobic exercise with low muscle glycogen on mTORC1 signaling and markers of myogenesis. Methods Eleven men completed two cycle ergometry glycogen depletion trials separated by 7-d, followed by randomized isocaloric refeeding for 24-h to elicit low (LOW; 1.5 g/kg carbohydrate, 3.0 g/kg fat) or adequate (AD; 6.0 g/kg carbohydrate, 1.0 g/kg fat) glycogen. Participants then performed 80-min of cycle ergometry (64 ± 3% VO2peak) while ingesting 146 g carbohydrate. mTORC1 signaling (Western blotting) and gene transcription (RT-qPCR) were determined from vastus lateralis biopsies before glycogen depletion (baseline, BASE), and before (PRE) and after (POST) exercise. Results Regardless of treatment, p-mTORC1Ser2448, p-p70S6KSer424/421, and p-rpS6Ser235/236 were higher (P < 0.05) POST compared to PRE and BASE. PAX7 and MYOGENIN were lower (P < 0.05) in LOW compared to AD, regardless of time, while MYOD was lower (P < 0.05) in LOW compared to AD at PRE, but not different at POST. Conclusion Initiating aerobic exercise with low muscle glycogen does not affect mTORC1 signaling, yet reductions in gene expression of myogenic regulatory factors suggest that muscle recovery from exercise may be reduced.
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Affiliation(s)
- Lee M Margolis
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, 10 General Greene Avenue, Bldg. 42, Natick, MA, 01760, USA.
| | - Marques A Wilson
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, 10 General Greene Avenue, Bldg. 42, Natick, MA, 01760, USA
| | - Claire C Whitney
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, 10 General Greene Avenue, Bldg. 42, Natick, MA, 01760, USA
| | - Christopher T Carrigan
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, 10 General Greene Avenue, Bldg. 42, Natick, MA, 01760, USA
| | - Nancy E Murphy
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, 10 General Greene Avenue, Bldg. 42, Natick, MA, 01760, USA
| | - Adrienne Hatch-McChesney
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, 10 General Greene Avenue, Bldg. 42, Natick, MA, 01760, USA
| | - Stefan M Pasiakos
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, 10 General Greene Avenue, Bldg. 42, Natick, MA, 01760, USA
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Xu T, Zhou H, Ma Z, Zhang H, Zeng Q, Xu D, Zhang Y, Zhang J. Congestive Heart Failure Exhibited Higher BMI With Lower Energy Intake and Lower Physical Activity Level: Data From the National Health and Examination Nutrition Survey. Front Cardiovasc Med 2021; 8:680371. [PMID: 34179144 PMCID: PMC8221290 DOI: 10.3389/fcvm.2021.680371] [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: 03/14/2021] [Accepted: 04/08/2021] [Indexed: 11/29/2022] Open
Abstract
Background: Despite that nutritional deficiency existed in congestive heart failure (CHF), there is a large amount of CHF patients suffering from obesity. This study aimed to identify the differences for increased BMI or obesity in CHF patients. Methods: This cross-sectional study included adults from the National Health and Nutrition Examination Survey 2007–2016. Differences were compared between CHF participants vs. non-CHF participants, and BMI ≥ 30 kg/m2 vs. BMI < 30 kg/m2 CHF participants. Results: CHF participants were with higher BMI, lower energy and macronutrient intake, lower physical activity level and longer rest time, and lower hematocrit and hemoglobin level (all P < 0.05) than non-CHF participants. The prevalence of BMI ≥ 30 kg/m2 in participants with CHF was 53.48%. There was no significant difference observed in energy and macronutrient intake between CHF participants with BMI ≥ 30 kg/m2 or <30 kg/m2. The water intake (P = 0.032), sedentary time (P = 0.002), and hematocrit (P = 0.028) were significantly different between CHF with BMI ≥ 30 kg/m2 and with <30 kg/m2. Conclusion: Compared with non-CHF participants, CHF participants exhibited higher BMI with lower energy and macronutrient intake, lower physical activity level, longer rest time, and hemodilution with lower hematocrit and hemoglobin level. Among CHF participants with BMI ≥ 30 kg/m2, higher sedentary time and hematocrit were observed.
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Affiliation(s)
- Tianyu Xu
- State Key Laboratory of Cardiovascular Disease, Heart Failure Center, National Center for Cardiovascular Disease, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Haobin Zhou
- State Key Laboratory of Organ Failure Research, Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Zhuang Ma
- State Key Laboratory of Organ Failure Research, Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Hao Zhang
- State Key Laboratory of Organ Failure Research, Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Qingchun Zeng
- State Key Laboratory of Organ Failure Research, Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Dingli Xu
- State Key Laboratory of Organ Failure Research, Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yuhui Zhang
- State Key Laboratory of Cardiovascular Disease, Heart Failure Center, National Center for Cardiovascular Disease, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Jian Zhang
- State Key Laboratory of Cardiovascular Disease, Heart Failure Center, National Center for Cardiovascular Disease, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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Regulation of Energy Substrate Metabolism in Endurance Exercise. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18094963. [PMID: 34066984 PMCID: PMC8124511 DOI: 10.3390/ijerph18094963] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/24/2021] [Accepted: 04/26/2021] [Indexed: 12/25/2022]
Abstract
The human body requires energy to function. Adenosine triphosphate (ATP) is the cellular currency for energy-requiring processes including mechanical work (i.e., exercise). ATP used by the cells is ultimately derived from the catabolism of energy substrate molecules—carbohydrates, fat, and protein. In prolonged moderate to high-intensity exercise, there is a delicate interplay between carbohydrate and fat metabolism, and this bioenergetic process is tightly regulated by numerous physiological, nutritional, and environmental factors such as exercise intensity and duration, body mass and feeding state. Carbohydrate metabolism is of critical importance during prolonged endurance-type exercise, reflecting the physiological need to regulate glucose homeostasis, assuring optimal glycogen storage, proper muscle fuelling, and delaying the onset of fatigue. Fat metabolism represents a sustainable source of energy to meet energy demands and preserve the ‘limited’ carbohydrate stores. Coordinated neural, hormonal and circulatory events occur during prolonged endurance-type exercise, facilitating the delivery of fatty acids from adipose tissue to the working muscle for oxidation. However, with increasing exercise intensity, fat oxidation declines and is unable to supply ATP at the rate of the exercise demand. Protein is considered a subsidiary source of energy supporting carbohydrates and fat metabolism, contributing to approximately 10% of total ATP turnover during prolonged endurance-type exercise. In this review we present an overview of substrate metabolism during prolonged endurance-type exercise and the regulatory mechanisms involved in ATP turnover to meet the energetic demands of exercise.
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11
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Fell JM, Hearris MA, Ellis DG, Moran JEP, Jevons EFP, Owens DJ, Strauss JA, Cocks M, Louis JB, Shepherd SO, Morton JP. Carbohydrate improves exercise capacity but does not affect subcellular lipid droplet morphology, AMPK and p53 signalling in human skeletal muscle. J Physiol 2021; 599:2823-2849. [PMID: 33772787 DOI: 10.1113/jp281127] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 03/22/2021] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Muscle glycogen and intramuscular triglycerides (IMTG, stored in lipid droplets) are important energy substrates during prolonged exercise. Exercise-induced changes in lipid droplet (LD) morphology (i.e. LD size and number) have not yet been studied under nutritional conditions typically adopted by elite endurance athletes, that is, after carbohydrate (CHO) loading and CHO feeding during exercise. We report for the first time that exercise reduces IMTG content in both central and peripheral regions of type I and IIa fibres, reflective of decreased LD number in both fibre types whereas reductions in LD size were exclusive to type I fibres. Additionally, CHO feeding does not alter subcellular IMTG utilisation, LD morphology or muscle glycogen utilisation in type I or IIa/II fibres. In the absence of alterations to muscle fuel selection, CHO feeding does not attenuate cell signalling pathways with regulatory roles in mitochondrial biogenesis. ABSTRACT We examined the effects of carbohydrate (CHO) feeding on lipid droplet (LD) morphology, muscle glycogen utilisation and exercise-induced skeletal muscle cell signalling. After a 36 h CHO loading protocol and pre-exercise meal (12 and 2 g kg-1 , respectively), eight trained males ingested 0, 45 or 90 g CHO h-1 during 180 min cycling at lactate threshold followed by an exercise capacity test (150% lactate threshold). Muscle biopsies were obtained pre- and post-completion of submaximal exercise. Exercise decreased (P < 0.01) glycogen concentration to comparable levels (∼700 to 250 mmol kg-1 DW), though utilisation was greater in type I (∼40%) versus type II fibres (∼10%) (P < 0.01). LD content decreased in type I (∼50%) and type IIa fibres (∼30%) (P < 0.01), with greater utilisation in type I fibres (P < 0.01). CHO feeding did not affect glycogen or IMTG utilisation in type I or II fibres (all P > 0.05). Exercise decreased LD number within central and peripheral regions of both type I and IIa fibres, though reduced LD size was exclusive to type I fibres. Exercise induced (all P < 0.05) comparable AMPKThr172 (∼4-fold), p53Ser15 (∼2-fold) and CaMKIIThr268 phosphorylation (∼2-fold) with no effects of CHO feeding (all P > 0.05). CHO increased exercise capacity where 90 g h-1 (233 ± 133 s) > 45 g h-1 (156 ± 66 s; P = 0.06) > 0 g h-1 (108 ± 54 s; P = 0.03). In conditions of high pre-exercise CHO availability, we conclude CHO feeding does not influence exercise-induced changes in LD morphology, glycogen utilisation or cell signalling pathways with regulatory roles in mitochondrial biogenesis.
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Affiliation(s)
- J Marc Fell
- Research Institute for Sport and Exercise Sciences (RISES), Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
| | - Mark A Hearris
- Research Institute for Sport and Exercise Sciences (RISES), Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
| | - Daniel G Ellis
- Research Institute for Sport and Exercise Sciences (RISES), Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
| | - James E P Moran
- Research Institute for Sport and Exercise Sciences (RISES), Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
| | - Emily F P Jevons
- Research Institute for Sport and Exercise Sciences (RISES), Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
| | - Daniel J Owens
- Research Institute for Sport and Exercise Sciences (RISES), Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
| | - Juliette A Strauss
- Research Institute for Sport and Exercise Sciences (RISES), Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
| | - Matthew Cocks
- Research Institute for Sport and Exercise Sciences (RISES), Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
| | - Julien B Louis
- Research Institute for Sport and Exercise Sciences (RISES), Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
| | - Sam O Shepherd
- Research Institute for Sport and Exercise Sciences (RISES), Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
| | - James P Morton
- Research Institute for Sport and Exercise Sciences (RISES), Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
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Jensen R, Ørtenblad N, Stausholm MLH, Skjaerbaek MC, Larsen DN, Hansen M, Holmberg HC, Plomgaard P, Nielsen J. Glycogen supercompensation is due to increased number, not size, of glycogen particles in human skeletal muscle. Exp Physiol 2021; 106:1272-1284. [PMID: 33675088 DOI: 10.1113/ep089317] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 03/01/2021] [Indexed: 01/10/2023]
Abstract
NEW FINDINGS What is the central question of this study? Glycogen supercompensation after glycogen-depleting exercise can be achieved by consuming a carbohydrate-enriched diet, but the associated effects on the size, number and localization of intramuscular glycogen particles are unknown. What is the main finding and its importance? Using transmission electron microscopy to inspect individual glycogen particles visually, we show that glycogen supercompensation is achieved by increasing the number of particles while keeping them at submaximal sizes. This might be a strategy to ensure that glycogen particles can be used fast, because particles that are too large might impair utilization rate. ABSTRACT Glycogen supercompensation after glycogen-depleting exercise can be achieved by consuming a carbohydrate-enriched diet, but the associated effects on the size, number and localization of intramuscular glycogen particles are unknown. We investigated how a glycogen-loading protocol affects fibre type-specific glycogen volume density, particle diameter and numerical density in three subcellular pools: between (intermyofibrillar) or within (intramyofibrillar) the myofibrils or beneath the sarcolemma (subsarcolemmal). Resting muscle biopsies from 11 physically active men were analysed using transmission electron microscopy after mixed (MIX), LOW or HIGH carbohydrate consumption separated by glycogen-lowering cycling at 75% of maximal oxygen consumption until exhaustion. After HIGH, the total volumetric glycogen content was 40% [95% confidence interval 16, 68] higher than after MIX in type I fibres (P < 0.001), with little to no difference in type II fibres (9% [95% confidence interval -9, 27]). Median particle diameter was 22.5 (interquartile range 20.8-24.7) nm across glycogen pools and fibre types, and the numerical density was 61% [25, 107] and 40% [9, 80] higher in the subsarcolemmal (P < 0.001) and intermyofibrillar (P < 0.01) pools of type I fibres, respectively, with little to no difference in the intramyofibrillar pool (3% [-20, 32]). In LOW, total glycogen was in the range of 21-23% lower, relative to MIX, in both fibre types, reflected in a 21-46% lower numerical density across pools. In comparison to MIX, particle diameter was unaffected by other diets ([-1.4, 1.3] nm). In conclusion, glycogen supercompensation after prolonged cycling is exclusive to type I fibres, predominantly in the subsarcolemmal pool, and involves an increase in the numerical density rather than the size of existing glycogen particles.
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Affiliation(s)
- Rasmus Jensen
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Niels Ørtenblad
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Marie-Louise H Stausholm
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Mette C Skjaerbaek
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Daniel N Larsen
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Mette Hansen
- Department of Public Health, Aarhus University, Aarhus, Denmark
| | - Hans-Christer Holmberg
- Department of Physiology and Pharmacology, Biomedicum C5, Karolinska Institutet, Stockholm, Sweden
| | - Peter Plomgaard
- Department of Clinical Biochemistry, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.,Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Joachim Nielsen
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
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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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Montanari S, Şahin MA, Lee BJ, Blacker SD, Willems ME. No Effects of New Zealand Blackcurrant Extract on Physiological and Performance Responses in Trained Male Cyclists Undertaking Repeated Testing across a Week Period. Sports (Basel) 2020; 8:sports8080114. [PMID: 32823733 PMCID: PMC7466623 DOI: 10.3390/sports8080114] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 07/15/2020] [Accepted: 08/11/2020] [Indexed: 01/22/2023] Open
Abstract
Anthocyanin supplements are receiving attention due to purported benefits to physiological, metabolic, and exercise responses in trained individuals. However, the efficacy of anthocyanin intake over multiple testing days is not known. We compared a placebo and two doses of anthocyanin-rich New Zealand blackcurrant (NZBC) extract (300 and 600 mg·day−1) on plasma lactate, substrate oxidation, and 16.1 km time trial (TT) performance on three occasions over 7-days in a fed state (day 1 (D1), D4, and D7). Thirteen male cyclists participated in a randomized, crossover, placebo-controlled double-blind design. There was no difference in plasma lactate and substrate oxidation between conditions and between days. A time difference was observed between D1 (1701 ± 163 s) and D4 (1682 ± 162 s) for 600 mg (p = 0.05), with an increment in average speed (D1 = 34.3 ± 3.4 vs. D4 = 34.8 ± 3.4 km·h−1, p = 0.04). However, there was no difference between the other days and between conditions. Overall, one week of intake of NZBC extract did not affect physiological and metabolic responses. Intake of 600 mg of NZBC extract showed inconsistent benefits in improving 16.1 km time trial performance over a week period in trained fed cyclists.
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Affiliation(s)
- Stefano Montanari
- Institute of Sport, University of Chichester, College Lane, Chichester PO19 6PE, UK; (S.M.); (M.A.Ş.); (B.J.L.); (S.D.B.)
| | - Mehmet A. Şahin
- Institute of Sport, University of Chichester, College Lane, Chichester PO19 6PE, UK; (S.M.); (M.A.Ş.); (B.J.L.); (S.D.B.)
- Department of Nutrition and Dietetics, Faculty of Health Sciences, Hacettepe University, Sihhiye, Ankara 06100, Turkey
| | - Ben J. Lee
- Institute of Sport, University of Chichester, College Lane, Chichester PO19 6PE, UK; (S.M.); (M.A.Ş.); (B.J.L.); (S.D.B.)
- Centre for Sport, Exercise and Life Sciences, Coventry University, Coventry CV1 5FB, UK
| | - Sam D. Blacker
- Institute of Sport, University of Chichester, College Lane, Chichester PO19 6PE, UK; (S.M.); (M.A.Ş.); (B.J.L.); (S.D.B.)
| | - Mark E.T. Willems
- Institute of Sport, University of Chichester, College Lane, Chichester PO19 6PE, UK; (S.M.); (M.A.Ş.); (B.J.L.); (S.D.B.)
- Correspondence:
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15
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Podlogar T, Free B, Wallis GA. High rates of fat oxidation are maintained after the sleep low approach despite delayed carbohydrate feeding during exercise. Eur J Sport Sci 2020; 21:213-223. [DOI: 10.1080/17461391.2020.1730447] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Tim Podlogar
- School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, UK
| | - Bonnie Free
- School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, UK
| | - Gareth A. Wallis
- School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, UK
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Malone JJ, MacLaren DPM, Campbell IT, Hulton AT. A 3-day dietary manipulation affects muscle glycogen and results in modifications of carbohydrate and fat metabolism during exercise when hyperglycaemic. Eur J Appl Physiol 2020; 120:873-882. [DOI: 10.1007/s00421-020-04326-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 02/12/2020] [Indexed: 01/25/2023]
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Margolis LM, Wilson MA, Whitney CC, Carrigan CT, Murphy NE, Hatch AM, Montain SJ, Pasiakos SM. Exercising with low muscle glycogen content increases fat oxidation and decreases endogenous, but not exogenous carbohydrate oxidation. Metabolism 2019; 97:1-8. [PMID: 31095946 DOI: 10.1016/j.metabol.2019.05.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 05/01/2019] [Accepted: 05/10/2019] [Indexed: 01/05/2023]
Abstract
BACKGROUND Initiating aerobic exercise with low muscle glycogen content promotes greater fat and less endogenous carbohydrate oxidation during exercise. However, the extent exogenous carbohydrate oxidation increases when exercise is initiated with low muscle glycogen is unclear. PURPOSE Determine the effects of muscle glycogen content at the onset of exercise on whole-body and muscle substrate metabolism. METHODS Using a randomized, crossover design, 12 men (mean ± SD, age: 21 ± 4 y; body mass: 83 ± 11 kg; VO2peak: 44 ± 3 mL/kg/min) completed 2 cycle ergometry glycogen depletion trials separated by 7-d, followed by a 24-h refeeding to elicit low (LOW; 1.5 g/kg carbohydrate, 3.0 g/kg fat) or adequate (AD; 6.0 g/kg carbohydrate, 1.0 g/kg fat) glycogen stores. Participants then performed 80 min of steady-state cycle ergometry (64 ± 3% VO2peak) while consuming a carbohydrate drink (95 g glucose +51 g fructose; 1.8 g/min). Substrate oxidation (g/min) was determined by indirect calorimetry and 13C. Muscle glycogen (mmol/kg dry weight), pyruvate dehydrogenase (PDH) activity, and gene expression were assessed in muscle. RESULTS Initiating steady-state exercise with LOW (217 ± 103) or AD (396 ± 70; P < 0.05) muscle glycogen did not alter exogenous carbohydrate oxidation (LOW: 0.84 ± 0.14, AD: 0.87 ± 0.16; P > 0.05) during exercise. Endogenous carbohydrate oxidation was lower and fat oxidation was higher in LOW (0.75 ± 0.29 and 0.55 ± 0.10) than AD (1.17 ± 0.29 and 0.38 ± 0.13; all P < 0.05). Before and after exercise PDH activity was lower (P < 0.05) and transcriptional regulation of fat metabolism (FAT, FABP, CPT1a, HADHA) was higher (P < 0.05) in LOW than AD. CONCLUSION Initiating exercise with low muscle glycogen does not impair exogenous carbohydrate oxidative capacity, rather, to compensate for lower endogenous carbohydrate oxidation acute adaptations lead to increased whole-body and skeletal muscle fat oxidation.
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Affiliation(s)
- Lee M Margolis
- U.S. Army Research Institute of Environmental Medicine, Natick, MA, United States of America; Oak Ridge Institute of Science and Education, Oak Ridge, TN, United States of America.
| | - Marques A Wilson
- U.S. Army Research Institute of Environmental Medicine, Natick, MA, United States of America
| | - Claire C Whitney
- U.S. Army Research Institute of Environmental Medicine, Natick, MA, United States of America
| | - Christopher T Carrigan
- U.S. Army Research Institute of Environmental Medicine, Natick, MA, United States of America
| | - Nancy E Murphy
- U.S. Army Research Institute of Environmental Medicine, Natick, MA, United States of America
| | - Adrienne M Hatch
- U.S. Army Research Institute of Environmental Medicine, Natick, MA, United States of America
| | - Scott J Montain
- U.S. Army Research Institute of Environmental Medicine, Natick, MA, United States of America
| | - Stefan M Pasiakos
- U.S. Army Research Institute of Environmental Medicine, Natick, MA, United States of America
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Hearris MA, Hammond KM, Seaborne RA, Stocks B, Shepherd SO, Philp A, Sharples AP, Morton JP, Louis JB. Graded reductions in preexercise muscle glycogen impair exercise capacity but do not augment skeletal muscle cell signaling: implications for CHO periodization. J Appl Physiol (1985) 2019; 126:1587-1597. [DOI: 10.1152/japplphysiol.00913.2018] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
We examined the effects of graded muscle glycogen on exercise capacity and modulation of skeletal muscle signaling pathways associated with the regulation of mitochondrial biogenesis. In a repeated-measures design, eight men completed a sleep-low, train-low model comprising an evening glycogen-depleting cycling protocol followed by an exhaustive exercise capacity test [8 × 3 min at 80% peak power output (PPO), followed by 1-min efforts at 80% PPO until exhaustion] the subsequent morning. After glycogen-depleting exercise, subjects ingested a total of 0 g/kg (L-CHO), 3.6 g/kg (M-CHO), or 7.6 g/kg (H-CHO) of carbohydrate (CHO) during a 6-h period before sleeping, such that exercise was commenced the next morning with graded ( P < 0.05) muscle glycogen concentrations (means ± SD: L-CHO: 88 ± 43, M-CHO: 185 ± 62, H-CHO: 278 ± 47 mmol/kg dry wt). Despite differences ( P < 0.05) in exercise capacity at 80% PPO between trials (L-CHO: 18 ± 7, M-CHO: 36 ± 3, H-CHO: 44 ± 9 min), exercise induced comparable AMPKThr172 phosphorylation (~4-fold) and PGC-1α mRNA expression (~5-fold) after exercise and 3 h after exercise, respectively. In contrast, neither exercise nor CHO availability affected the phosphorylation of p38MAPKThr180/Tyr182 or CaMKIIThr268 or mRNA expression of p53, Tfam, CPT-1, CD36, or PDK4. Data demonstrate that when exercise is commenced with muscle glycogen < 300 mmol/kg dry wt, further graded reductions of 100 mmol/kg dry weight impair exercise capacity but do not augment skeletal muscle cell signaling. NEW & NOTEWORTHY We provide novel data demonstrating that when exercise is commenced with muscle glycogen below 300 mmol/kg dry wt (as achieved with the sleep-low, train-low model) further graded reductions in preexercise muscle glycogen of 100 mmol/kg dry wt reduce exercise capacity at 80% peak power output by 20–50% but do not augment skeletal muscle cell signaling.
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Affiliation(s)
- Mark A. Hearris
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Kelly M. Hammond
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Robert A. Seaborne
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Ben Stocks
- Medial Research Council-Arthritis Research UK Centre for Musculoskeletal Aging Research, School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Sam O. Shepherd
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Andrew Philp
- Medial Research Council-Arthritis Research UK Centre for Musculoskeletal Aging Research, School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom
- Diabetes and Metabolism Division, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | - Adam P. Sharples
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
- Institute for Science and Technology in Medicine, Keele University, Guy Hilton Research Centre, Stoke-on-Trent, United Kingdom
| | - James P. Morton
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Julien B. Louis
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
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19
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Bianchi VE. Impact of Nutrition on Cardiovascular Function. Curr Probl Cardiol 2018; 45:100391. [PMID: 30318107 DOI: 10.1016/j.cpcardiol.2018.08.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 08/31/2018] [Indexed: 12/11/2022]
Abstract
The metabolic sources of energy for myocardial contractility include mainly free fatty acids (FFA) for 95%, and in lesser amounts for 5% from glucose and minimal contributions from other substrates such lactate, ketones, and amino acids. However, myocardial efficiency is influenced by metabolic condition, overload, and ischemia. During cardiac stress, cardiomyocytes increase glucose oxidation and reduce FFA oxidation. In patients with ischemic coronary disease and heart failure, the low oxygen availability limits myocardial reliance on FFA and glucose utilization must increase. Although glucose uptake is fundamental to cardiomyocyte function, an excessive intracellular glucose level is detrimental. Insulin plays a fundamental role in maintaining myocardial efficiency and in reducing glycemia and inflammation; this is particularly evident in obese and type-2 diabetic patients. An excess of F availability increase fat deposition within cardiomyocytes and reduces glucose oxidation. In patients with high body mass index, a restricted diet or starvation have positive effects on cardiac metabolism and function while, in patients with low body mass index, restrictive diets, or starvation have a deleterious effect. Thus, weight loss in obese patients has positive impacts on ventricular mass and function, whereas, in underweight heart failure patients, such weight reduction adds to the risk of heart damage, predisposing to cachexia. Nutrition plays an essential role in the evolution of cardiovascular disease and should be taken into account. An energy-restricted diet improves myocardial efficiency but can represent a potential risk of heart damage, particularly in patients affected by cardiovascular disease. Micronutrient integration has a marginal effect on cardiovascular efficiency.
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Bezborodkina NN, Chestnova AY, Vorobev ML, Kudryavtsev BN. Spatial Structure of Glycogen Molecules in Cells. BIOCHEMISTRY (MOSCOW) 2018; 83:467-482. [PMID: 29738682 DOI: 10.1134/s0006297918050012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Glycogen is a strongly branched polymer of α-D-glucose, with glucose residues in the linear chains linked by 1→4-bonds (~93% of the total number of bonds) and with branching after every 4-8 residues formed by 1→6-glycosidic bonds (~7% of the total number of bonds). It is thought currently that a fully formed glycogen molecule (β-particle) with the self-glycosylating protein glycogenin in the center has a spherical shape with diameter of ~42 nm and contains ~ 55,000 glucose residues. The glycogen molecule also includes numerous proteins involved in its synthesis and degradation, as well as proteins performing a carcass function. However, the type and force of bonds connecting these proteins to the polysaccharide moiety of glycogen are significantly different. This review presents the available data on the spatial structure of the glycogen molecule and its changes under various physiological and pathological conditions.
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Affiliation(s)
- N N Bezborodkina
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064, Russia.
| | - A Yu Chestnova
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064, Russia
| | - M L Vorobev
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064, Russia
| | - B N Kudryavtsev
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064, Russia
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Ferreira GA, Felippe LC, Silva RLS, Bertuzzi R, De Oliveira FR, Pires FO, Lima-Silva AE. Effect of pre-exercise carbohydrate availability on fat oxidation and energy expenditure after a high-intensity exercise. ACTA ACUST UNITED AC 2018; 51:e6964. [PMID: 29590260 PMCID: PMC5886548 DOI: 10.1590/1414-431x20186964] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 02/02/2018] [Indexed: 11/22/2022]
Abstract
The aim of this study was to test the hypothesis that reduced pre-exercise carbohydrate (CHO) availability potentiates fat oxidation after an exhaustive high-intensity exercise bout. Eight physically active men underwent a high-intensity exercise (∼95% V̇O2max) until exhaustion under low or high pre-exercise CHO availability. The protocol to manipulate pre-exercise CHO availability consisted of a 90-min cycling bout at ∼70% V̇O2max + 6 × 1-min at 125% V̇O2max with 1-min rest, followed by 48 h under a low- (10% CHO, low-CHO availability) or high-CHO diet (80% CHO, high-CHO availability). Time to exhaustion was shorter and energy expenditure (EE) lower during the high-intensity exercise in low- compared to high-CHO availability (8.6±0.8 and 11.4±1.6 min, and 499±209 and 677±343 kJ, respectively, P<0.05). Post-exercise EE was similar between low- and high-CHO availability (425±147 and 348±54 kJ, respectively, P>0.05), but post-exercise fat oxidation was significantly higher (P<0.05) in low- (7,830±1,864 mg) than in high-CHO availability (6,264±1,763 mg). The total EE (i.e., exercise EE plus post-exercise EE) was similar between low- and high-CHO availability (924±264 and 1,026±340 kJ, respectively, P>0.05). These results suggest that a single bout of high-intensity exercise performed under low-CHO availability increased post-exercise fat oxidation, and even with shorter exercise duration, both post-exercise EE and total EE were not impaired.
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Affiliation(s)
- G A Ferreira
- Grupo de Pesquisa em Ciências do Esporte, Centro Acadêmico de Vitória, Universidade Federal de Pernambuco, Vitória de Santo Antão, PE, Brasil
| | - L C Felippe
- Grupo de Pesquisa em Ciências do Esporte, Centro Acadêmico de Vitória, Universidade Federal de Pernambuco, Vitória de Santo Antão, PE, Brasil
| | - R L S Silva
- Grupo de Pesquisa em Ciências do Esporte, Centro Acadêmico de Vitória, Universidade Federal de Pernambuco, Vitória de Santo Antão, PE, Brasil
| | - R Bertuzzi
- Grupo de Estudos em Desempenho Aeróbio, Escola de Educação Física e Esporte, Universidade de São Paulo, São Paulo, SP, Brasil
| | - F R De Oliveira
- Núcleo de Estudos do Movimento Humano, Departamento de Educação Física, Universidade Federal de Lavras, Lavras, MG, Brasil
| | - F O Pires
- Grupo de Estudos em Psico-fisiologia do Exercício, Escola de Artes, Ciências e Humanidades, Universidade de São Paulo, São Paulo, SP, Brasil
| | - A E Lima-Silva
- Grupo de Pesquisa em Ciências do Esporte, Centro Acadêmico de Vitória, Universidade Federal de Pernambuco, Vitória de Santo Antão, PE, Brasil.,Grupo de Pesquisa Desempenho Humano, Universidade Tecnológica Federal do Paraná, Curitiba, PR, Brasil
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Tomcik KA, Camera DM, Bone JL, Ross ML, Jeacocke NA, Tachtsis B, Senden J, VAN Loon LJC, Hawley JA, Burke LM. Effects of Creatine and Carbohydrate Loading on Cycling Time Trial Performance. Med Sci Sports Exerc 2018; 50:141-150. [PMID: 28806275 DOI: 10.1249/mss.0000000000001401] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
INTRODUCTION Creatine (Cr) and carbohydrate loadings are dietary strategies used to enhance exercise capacity. This study examined the metabolic and performance effects of a combined CR and CHO loading regiment on time trial (TT) cycling bouts. METHODS Eighteen well-trained (~65 mL·kg·min V˙O2peak) men completed three performance trials (PT) that comprised a 120-km cycling TT interspersed with alternating 1- and 4-km sprints (six sprints each) performed every 10 km followed by an inclined ride to fatigue (~90% V˙O2peak). Subjects were pair matched into either CR-loaded (20 g·d for 5 d + 3 g·d for 9 d) or placebo (PLA) groups (n = 9) after the completion of PT1. All subjects undertook a crossover application of the carbohydrate interventions, consuming either moderate (6 g·kg body mass (BM) per day; MOD) or CHO-loaded (12 g·kg BM·d; LOAD) diets before PT2 and PT3. Muscle biopsies were taken before PT1, 18 h after PT1, and before both PT2 and PT3. RESULTS No significant differences in overall TT or inclined ride times were observed between intervention groups. PLA + LOAD improved power above baseline (P < 0.05) during the final 1-km sprint, whereas CR + MOD and CR + LOAD improved power (P < 0.05) during the final 4-km sprint. Greater power was achieved with MOD and LOAD compared with baseline with PLA (P < 0.05). CR increased pre-PT BM compared with PLA (+1.54% vs +0.99% from baseline). CR + LOAD facilitated greater [total CR] (P < 0.05 vs baseline) and muscle [glycogen] (P < 0.01 vs baseline and MOD) compared with PLA + LOAD. Mechanistic target of rapamycin decreased from baseline after glycogen depletion (~30%; P < 0.05). CONCLUSIONS Power output in the closing sprints of exhaustive TT cycling increased with CR ingestion despite a CR-mediated increase in weight. CR cosupplemented with carbohydrates may therefore be beneficial strategy for late-stage breakaway moments in endurance events.
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Affiliation(s)
- Kristyen A Tomcik
- 1Centre for Exercise and Nutrition, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Victoria, AUSTRALIA; 2Sports Nutrition, Australian Institute of Sport, Belconnen, Australian Capital Territory, AUSTRALIA; 3NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre, Maastricht, THE NETHERLANDS; and 4Research Institute for Sports and Exercise Sciences, Liverpool John Moores University, Liverpool, UNITED KINGDOM
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Regulation of Muscle Glycogen Metabolism during Exercise: Implications for Endurance Performance and Training Adaptations. Nutrients 2018; 10:nu10030298. [PMID: 29498691 PMCID: PMC5872716 DOI: 10.3390/nu10030298] [Citation(s) in RCA: 119] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 02/23/2018] [Accepted: 02/27/2018] [Indexed: 11/16/2022] Open
Abstract
Since the introduction of the muscle biopsy technique in the late 1960s, our understanding of the regulation of muscle glycogen storage and metabolism has advanced considerably. Muscle glycogenolysis and rates of carbohydrate (CHO) oxidation are affected by factors such as exercise intensity, duration, training status and substrate availability. Such changes to the global exercise stimulus exert regulatory effects on key enzymes and transport proteins via both hormonal control and local allosteric regulation. Given the well-documented effects of high CHO availability on promoting exercise performance, elite endurance athletes are typically advised to ensure high CHO availability before, during and after high-intensity training sessions or competition. Nonetheless, in recognition that the glycogen granule is more than a simple fuel store, it is now also accepted that glycogen is a potent regulator of the molecular cell signaling pathways that regulate the oxidative phenotype. Accordingly, the concept of deliberately training with low CHO availability has now gained increased popularity amongst athletic circles. In this review, we present an overview of the regulatory control of CHO metabolism during exercise (with a specific emphasis on muscle glycogen utilization) in order to discuss the effects of both high and low CHO availability on modulating exercise performance and training adaptations, respectively.
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Gejl KD, Ørtenblad N, Andersson E, Plomgaard P, Holmberg H, Nielsen J. Local depletion of glycogen with supramaximal exercise in human skeletal muscle fibres. J Physiol 2017; 595:2809-2821. [PMID: 27689320 PMCID: PMC5407966 DOI: 10.1113/jp273109] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 09/26/2016] [Indexed: 01/29/2023] Open
Abstract
KEY POINTS Glycogen is stored in local spatially distinct compartments within skeletal muscle fibres and is the main energy source during supramaximal exercise. Using quantitative electron microscopy, we show that supramaximal exercise induces a differential depletion of glycogen from these compartments and also demonstrate how this varies with fibre types. Repeated exercise alters this compartmentalized glycogen depletion. The results obtained in the present study help us understand the muscle metabolic dynamics of whole body repeated supramaximal exercise, and suggest that the muscle has a compartmentalized local adaptation to repeated exercise, which affects glycogen depletion. ABSTRACT Skeletal muscle glycogen is heterogeneously distributed in three separated compartments (intramyofibrillar, intermyofibrillar and subsarcolemmal). Although only constituting 3-13% of the total glycogen volume, the availability of intramyofibrillar glycogen is of particular importance to muscle function. The present study aimed to investigate the depletion of these three subcellular glycogen compartments during repeated supramaximal exercise in elite athletes. Ten elite cross-country skiers (aged 25 ± 4 years, V̇O2 max : 65 ± 4 ml kg-1 min-1 ; mean ± SD) performed four ∼4 min supramaximal sprint time trials (STT 1-4) with 45 min of recovery. The subcellular glycogen volumes in musculus triceps brachii were quantified from electron microscopy images before and after both STT 1 and 4. During STT 1, the depletion of intramyofibrillar glycogen was higher in type 1 fibres [-52%; (-89:-15%)] than type 2 fibres [-15% (-52:22%)] (P = 0.02), whereas the depletion of intermyofibrillar glycogen [main effect: -19% (-33:0%), P = 0.006] and subsarcolemmal glycogen [main effect: -35% (-66:0%), P = 0.03] was similar between fibre types. By contrast, only intermyofibrillar glycogen volume was significantly reduced during STT 4, in both fibre types [main effect: -31% (-50:-11%), P = 0.002]. Furthermore, for each of the subcellular compartments, the depletion of glycogen during STT 1 was associated with the volumes of glycogen before STT 1. In conclusion, the depletion of spatially distinct glycogen compartments differs during supramaximal exercise. Furthermore, the depletion changes with repeated exercise and is fibre type-dependent.
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Affiliation(s)
- Kasper D. Gejl
- Department of Sports Science and Clinical BiomechanicsSDU Muscle Research ClusterUniversity of Southern DenmarkOdenseDenmark
| | - Niels Ørtenblad
- Department of Sports Science and Clinical BiomechanicsSDU Muscle Research ClusterUniversity of Southern DenmarkOdenseDenmark
- Swedish Winter Sports Research CentreDepartment of Health SciencesMid Sweden UniversityÖstersundSweden
| | - Erik Andersson
- Swedish Winter Sports Research CentreDepartment of Health SciencesMid Sweden UniversityÖstersundSweden
| | - Peter Plomgaard
- The Centre of Inflammation and MetabolismDepartment of Infectious Diseases and CMRCRigshospitaletCopenhagenDenmark
- Department of Clinical BiochemistryRigshospitaletCopenhagenDenmark
| | - Hans‐Christer Holmberg
- Swedish Winter Sports Research CentreDepartment of Health SciencesMid Sweden UniversityÖstersundSweden
- Swedish Olympic CommitteeStockholmSweden
| | - Joachim Nielsen
- Department of Sports Science and Clinical BiomechanicsSDU Muscle Research ClusterUniversity of Southern DenmarkOdenseDenmark
- Department of PathologySDU Muscle Research ClusterOdense University HospitalOdense
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Poorer Intermittent Sprints Performance in Ramadan-Fasted Muslim Footballers despite Controlling for Pre-Exercise Dietary Intake, Sleep and Training Load. Sports (Basel) 2017; 5:sports5010004. [PMID: 29910364 PMCID: PMC5969002 DOI: 10.3390/sports5010004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 12/23/2016] [Accepted: 12/28/2016] [Indexed: 11/20/2022] Open
Abstract
This study examines the effects of Ramadan fasting on sprint performance during prolonged intermittent exercise in trained Muslim footballers, under controlled pre-exercise conditions. A within-group, cross-over study design with two non-fasted or Control trials performed before (i.e., CON1) and after (CON2) the Ramadan month, and with the Ramadan-fasted (RAM) trials performed within the Ramadan month. After familiarization, 14 players completed a modified 60-min (4 × 15-min exercise blocks interspersed with 3-min intervals) of the Loughborough Intermittent Shuttle Test (mLIST) of fixed speeds of walking, jogging, running, but with all-out effort sprints. During the interval periods, capillary blood glucose and blood lactate measures were taken, rectal and skin temperatures were recorded and maximal voluntary isometric contractions (MVIC) of the dominant leg and hand-grip were performed to provide some indication to the cause(s) of ‘fatigue’ during exercise. Players were provided with standardized 24-h pre-packed meals prior to all trials. Sleep hours were objectively assessed and perceived training loads were monitored and these were equivalent between RAM and CON trials. Sprint times throughout mLIST were significantly faster in both CON1 and CON2 as compared to RAM trials (all P < 0.017; d = small to moderate), and this poorer performance in RAM was observed as early as during the first 15-min of the mLIST. Blood markers, MVIC and thermoregulatory results were not substantially different between both CON and RAM trials. In conclusion, despite similarities in dietary intake, sleeping hours and training loads between conditions, results still indicate that Ramadan fasting had an adverse effect on prolonged intermittent performance. Nocebo effects plays a dominant role during exercise in the Ramadan-fasted state.
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Webster CC, Noakes TD, Chacko SK, Swart J, Kohn TA, Smith JAH. Gluconeogenesis during endurance exercise in cyclists habituated to a long-term low carbohydrate high-fat diet. J Physiol 2016; 594:4389-405. [PMID: 26918583 DOI: 10.1113/jp271934] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 02/23/2016] [Indexed: 12/18/2022] Open
Abstract
KEY POINTS Blood glucose is an important fuel for endurance exercise. It can be derived from ingested carbohydrate, stored liver glycogen and newly synthesized glucose (gluconeogenesis). We hypothesized that athletes habitually following a low carbohydrate high fat (LCHF) diet would have higher rates of gluconeogenesis during exercise compared to those who follow a mixed macronutrient diet. We used stable isotope tracers to study glucose production kinetics during a 2 h ride in cyclists habituated to either a LCHF or mixed macronutrient diet. The LCHF cyclists had lower rates of total glucose production and hepatic glycogenolysis but similar rates of gluconeogenesis compared to those on the mixed diet. The LCHF cyclists did not compensate for reduced dietary carbohydrate availability by increasing glucose synthesis during exercise but rather adapted by altering whole body substrate utilization. ABSTRACT Endogenous glucose production (EGP) occurs via hepatic glycogenolysis (GLY) and gluconeogenesis (GNG) and plays an important role in maintaining euglycaemia. Rates of GLY and GNG increase during exercise in athletes following a mixed macronutrient diet; however, these processes have not been investigated in athletes following a low carbohydrate high fat (LCHF) diet. Therefore, we studied seven well-trained male cyclists that were habituated to either a LCHF (7% carbohydrate, 72% fat, 21% protein) or a mixed diet (51% carbohydrate, 33% fat, 16% protein) for longer than 8 months. After an overnight fast, participants performed a 2 h laboratory ride at 72% of maximal oxygen consumption. Glucose kinetics were measured at rest and during the final 30 min of exercise by infusion of [6,6-(2) H2 ]-glucose and the ingestion of (2) H2 O tracers. Rates of EGP and GLY both at rest and during exercise were significantly lower in the LCHF group than the mixed diet group (Exercise EGP: LCHF, 6.0 ± 0.9 mg kg(-1) min(-1) , Mixed, 7.8 ± 1.1 mg kg(-1) min(-1) , P < 0.01; Exercise GLY: LCHF, 3.2 ± 0.7 mg kg(-1) min(-1) , Mixed, 5.3 ± 0.9 mg kg(-1) min(-1) , P < 0.01). Conversely, no difference was detected in rates of GNG between groups at rest or during exercise (Exercise: LCHF, 2.8 ± 0.4 mg kg(-1) min(-1) , Mixed, 2.5 ± 0.3 mg kg(-1) min(-1) , P = 0.15). We conclude that athletes on a LCHF diet do not compensate for reduced glucose availability via higher rates of glucose synthesis compared to athletes on a mixed diet. Instead, GNG remains relatively stable, whereas glucose oxidation and GLY are influenced by dietary factors.
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Affiliation(s)
- Christopher C Webster
- Division of Exercise Science and Sports Medicine (ESSM), Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Newlands, South Africa
| | - Timothy D Noakes
- Division of Exercise Science and Sports Medicine (ESSM), Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Newlands, South Africa
| | - Shaji K Chacko
- Department of Pediatrics, Children's Nutrition Research Center, US Department of Agriculture/Agricultural Research Service, Baylor College of Medicine, Houston, TX, USA
| | - Jeroen Swart
- Division of Exercise Science and Sports Medicine (ESSM), Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Newlands, South Africa
| | - Tertius A Kohn
- Division of Exercise Science and Sports Medicine (ESSM), Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Newlands, South Africa
| | - James A H Smith
- Division of Exercise Science and Sports Medicine (ESSM), Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Newlands, South Africa
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Jayewardene AF, Mavros Y, Gwinn T, Hancock DP, Rooney KB. Associations between CD36 gene polymorphisms and metabolic response to a short-term endurance-training program in a young-adult population. Appl Physiol Nutr Metab 2016; 41:157-67. [PMID: 26830498 DOI: 10.1139/apnm-2015-0430] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent studies have shown that CD36 gene variants are associated with an increased prevalence of chronic disease. Although a genetic component to trainability has been proven, no data are available specifically on the influence of CD36 on training response. Two single nucleotide polymorphisms (SNPs) (rs1527479 and rs1984112) were assessed for associations with whole-body substrate oxidation, response to a 75-g dextrose oral glucose tolerance test, fasting plasma lipids, and cardiovascular disease risk factors in a young healthy cohort, both using cross-sectional analysis and following a 4-week endurance-exercise training program. Genotyping was performed using real-time polymerase chain reaction. Cross-sectional data were collected in 34 individuals (age, 22.7 ± 3.5 years), with 17 completing the training program. At baseline, TT SNP carriers at rs1527479 and wild-type GG carriers at rs1984112 were associated with significantly greater whole-body rate of fat oxidation (Fatox) during submaximal exercise (P < 0.05), whilst AA carriers at the same position were associated with elevated triglyceride (TG) levels. A significant genotype × time interaction in Fatox at SNP rs1984112 was identified at rest. Significant genotype × time interactions were present at rs1527479, with TT carriers exhibiting a favourable response to training when compared with C-allele carriers for fasting TG, diastolic blood pressure (DBP), and mean arterial pressure (MAP). In conclusion, cross-sectional assessment identified associations with Fatox and TG. Training response at both SNPs identified "at-risk" genotypes responding favourably to the training stimulus in Fatox, TG, DBP, and MAP. Although these data show potential pleiotropic influence of CD36 SNPs, assessment in a larger cohort is warranted.
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Affiliation(s)
- Avindra F Jayewardene
- a Exercise Health and Performance Faculty Research Group, Faculty of Health Sciences, University of Sydney, Lidcombe, NSW, Australia
| | - Yorgi Mavros
- a Exercise Health and Performance Faculty Research Group, Faculty of Health Sciences, University of Sydney, Lidcombe, NSW, Australia
| | - Tom Gwinn
- a Exercise Health and Performance Faculty Research Group, Faculty of Health Sciences, University of Sydney, Lidcombe, NSW, Australia
| | - Dale P Hancock
- b School of Molecular Biosciences, Faculty of Science, University of Sydney, Camperdown, NSW, Australia
| | - Kieron B Rooney
- a Exercise Health and Performance Faculty Research Group, Faculty of Health Sciences, University of Sydney, Lidcombe, NSW, Australia
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Lima-Silva AE, Pires FO, Bertuzzi RCM, Lira FS, Casarini D, Kiss MAPDM. Low carbohydrate diet affects the oxygen uptake on-kinetics and rating of perceived exertion in high intensity exercise. Psychophysiology 2015; 48:277-84. [PMID: 20624251 DOI: 10.1111/j.1469-8986.2010.01059.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The aim of this study was to determine if the carbohydrate (CHO) availability alters the rate of increase in the rating of perceived exertion (RPE) during high intensity exercise and whether this would be associated with physiological changes. Six males performed high intensity exercise after 48 h of controlled, high CHO (80%) and low CHO (10%) diets. Time to exhaustion was lower in the low compared to high CHO diet. The rate of increase in RPE was greater and the VO2 slow component was lower in the low CHO diet than in the control. There was no significant condition effect for cortisol, insulin, pH, plasma glucose, potassium, or lactate concentrations. Multiple linear regression indicated that the total amplitude of VO2 and perceived muscle strain accounted for the greatest variance in the rate of increase in RPE. These results suggest that cardiorespiratory variables and muscle strain are important afferent signals from the periphery for the RPE calculations.
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Affiliation(s)
- Adriano E Lima-Silva
- School of Physical Education and Sport, University of São Paulo, São Paulo, BrazilSports Science Research Group, Federal University of Alagoas, Maceió, BrazilDepartment of Physiology, Division of Nutrition Physiology, Federal University of São Paulo, São Paulo, BrazilNephrology Division, Hospital of the Kidney and Hypertension, Federal University of São Paulo, São Paulo, Brazil
| | - FláVio O Pires
- School of Physical Education and Sport, University of São Paulo, São Paulo, BrazilSports Science Research Group, Federal University of Alagoas, Maceió, BrazilDepartment of Physiology, Division of Nutrition Physiology, Federal University of São Paulo, São Paulo, BrazilNephrology Division, Hospital of the Kidney and Hypertension, Federal University of São Paulo, São Paulo, Brazil
| | - Rômulo C M Bertuzzi
- School of Physical Education and Sport, University of São Paulo, São Paulo, BrazilSports Science Research Group, Federal University of Alagoas, Maceió, BrazilDepartment of Physiology, Division of Nutrition Physiology, Federal University of São Paulo, São Paulo, BrazilNephrology Division, Hospital of the Kidney and Hypertension, Federal University of São Paulo, São Paulo, Brazil
| | - Fábio S Lira
- School of Physical Education and Sport, University of São Paulo, São Paulo, BrazilSports Science Research Group, Federal University of Alagoas, Maceió, BrazilDepartment of Physiology, Division of Nutrition Physiology, Federal University of São Paulo, São Paulo, BrazilNephrology Division, Hospital of the Kidney and Hypertension, Federal University of São Paulo, São Paulo, Brazil
| | - Dulce Casarini
- School of Physical Education and Sport, University of São Paulo, São Paulo, BrazilSports Science Research Group, Federal University of Alagoas, Maceió, BrazilDepartment of Physiology, Division of Nutrition Physiology, Federal University of São Paulo, São Paulo, BrazilNephrology Division, Hospital of the Kidney and Hypertension, Federal University of São Paulo, São Paulo, Brazil
| | - Maria Augusta P D M Kiss
- School of Physical Education and Sport, University of São Paulo, São Paulo, BrazilSports Science Research Group, Federal University of Alagoas, Maceió, BrazilDepartment of Physiology, Division of Nutrition Physiology, Federal University of São Paulo, São Paulo, BrazilNephrology Division, Hospital of the Kidney and Hypertension, Federal University of São Paulo, São Paulo, Brazil
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29
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Abstract
A major goal of training to improve the performance of prolonged, continuous, endurance events lasting up to 3 h is to promote a range of physiological and metabolic adaptations that permit an athlete to work at both higher absolute and relative power outputs/speeds and delay the onset of fatigue (i.e., a decline in exercise intensity). To meet these goals, competitive endurance athletes undertake a prodigious volume of training, with a large proportion performed at intensities that are close to or faster than race pace and highly dependent on carbohydrate (CHO)-based fuels to sustain rates of muscle energy production [i.e., match rates of adenosine triphosphate (ATP) hydrolysis with rates of resynthesis]. Consequently, to sustain muscle energy reserves and meet the daily demands of training sessions, competitive athletes freely select CHO-rich diets. Despite renewed interest in high-fat, low-CHO diets for endurance sport, fat-rich diets do not improve training capacity or performance, but directly impair rates of muscle glycogenolysis and energy flux, limiting high-intensity ATP production. When highly trained athletes compete in endurance events lasting up to 3 h, CHO-, not fat-based fuels are the predominant fuel for the working muscles and CHO, not fat, availability becomes rate limiting for performance.
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Affiliation(s)
- John A Hawley
- The Mary MacKillop Institute for Health Research, Centre for Exercise and Nutrition, Australian Catholic University, Locked Bag 4115, Fitzroy, VIC, 3065, Australia.
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK.
| | - Jill J Leckey
- The Mary MacKillop Institute for Health Research, Centre for Exercise and Nutrition, Australian Catholic University, Locked Bag 4115, Fitzroy, VIC, 3065, Australia
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30
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Cunha VN, de Paula Lima M, Motta-Santos D, Pesquero JL, de Andrade RV, de Almeida JA, Araujo RC, Grubert Campbell CS, Lewis JE, Simões HG. Role of exercise intensity on GLUT4 content, aerobic fitness and fasting plasma glucose in type 2 diabetic mice. Cell Biochem Funct 2015; 33:435-42. [DOI: 10.1002/cbf.3128] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 08/03/2015] [Accepted: 08/04/2015] [Indexed: 12/25/2022]
Affiliation(s)
- Verusca Najara Cunha
- Graduate Program on Physical Education and Health; Catholic University of Brasilia; Brasília DF Brazil
| | - Mérica de Paula Lima
- Department of Physiology and Biophysics, Institute of Biological Sciences; Federal University of Minas Gerais; Belo Horizonte MG Brazil
- Basic Nursing Department; School of Nursing, Federal University of Minas Gerais; Belo Horizonte MG Brazil
| | - Daisy Motta-Santos
- Department of Physiology and Biophysics, Institute of Biological Sciences; Federal University of Minas Gerais; Belo Horizonte MG Brazil
- National Institute of Science and Technology in Nanobiopharmaceutics (INCT-NANOBIOFAR); Belo Horizonte MG Brazil
| | - Jorge Luiz Pesquero
- Department of Physiology and Biophysics, Institute of Biological Sciences; Federal University of Minas Gerais; Belo Horizonte MG Brazil
| | | | - Jeeser Alves de Almeida
- National Institute of Science and Technology in Nanobiopharmaceutics (INCT-NANOBIOFAR); Belo Horizonte MG Brazil
| | | | | | - John E. Lewis
- Department of Psychiatry and Behavioral Sciences; University of Miami Miller School of Medicine; Miami FL USA
| | - Herbert Gustavo Simões
- Graduate Program on Physical Education and Health; Catholic University of Brasilia; Brasília DF Brazil
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31
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Kasper AM, Cocking S, Cockayne M, Barnard M, Tench J, Parker L, McAndrew J, Langan-Evans C, Close GL, Morton JP. Carbohydrate mouth rinse and caffeine improves high-intensity interval running capacity when carbohydrate restricted. Eur J Sport Sci 2015; 16:560-8. [DOI: 10.1080/17461391.2015.1041063] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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32
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Colberg SR. Exercise as medicine for diabetes: prescribing appropriate activities and avoiding potential pitfalls: preface. Diabetes Spectr 2015; 28:10-3. [PMID: 25717272 PMCID: PMC4334086 DOI: 10.2337/diaspect.28.1.10] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Sheri R Colberg
- Old Dominion University and Eastern Virginia Medical School, Norfolk, VA
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33
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Rubini A, Parmagnani A, Paoli A. Metabolic and ventilatory effects of oral glucose load at rest and during incremental aerobic muscular work in young healthy adults. ACTA PHYSIOLOGICA HUNGARICA 2014; 101:197-204. [PMID: 24901080 DOI: 10.1556/aphysiol.101.2014.2.8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We measured respiratory ratio (RR), pulmonary ventilation (VE) and end-tidal carbon dioxide partial pressure (ETPCO2) at rest and during cycling aerobic workloads (20%, 40%, 60% of estimated maximal oxygen uptake). Measurements were taken after overnight fasting and after an oral glucose load. RR, VE and ETPCO2 increased with workload. Glucose load caused RR and VE increments at rest (0.75 ± 0.01 vs. 0.86 ± 0.02, p < 0.01, and 10.8 ± 0.43 vs. 12.1 ± 0.49 l/min, p < 0.01, respectively) and for each workload (20% estimated maximal oxygen uptake: 0.77 ± 0.01 vs. 0.855 ± 0.02, p < 0.01, and 16.2 ± 0.73 vs. 17.7 ± 0.8 l/min, p < 0.01; 40% estimated maximal oxygen uptake: 0.76 ± 0.02 vs. 0.82 ± 0.01, p < 0.01, and 25.9 ± 1.1 vs. 28.3 ± 1.3 l/min, p < 0.05; 60% estimated maximal oxygen uptake: 0.85 ± 0.02 vs. 0.91 ± 0.02, p < 0.01, and 37.4 ± 1.7 vs. 40.9 ± 1.9 l/min, p < 0.05) but ETPCO2 did not change. The differences in RR before and after glucose load became smaller as the workload increased. Linear regression analysis of VE and carbon dioxide output yielded virtually identical results for both fasting and glucose load conditions. We have concluded that: a) for the metabolic carbon dioxide load increment due to glucose-induced RR increment, the physiological response is an increase of VE at all workloads. This response modulates constant ETPCO2 values; b) on workload increment, skeletal muscle increasingly utilises more and more glycogen stores, regardless of the blood glucose availability. This reduces the usefulness of dietary manipulations decreasing carbon dioxide metabolic load during muscular work in respiratory failure; c) the absolute value of metabolic carbon dioxide load exerts a role in ventilation regulation at rest and during aerobic exercise.
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Affiliation(s)
- A Rubini
- University of Padova Department of Biomedical Sciences Via Marzolo 3 35100 Padova Italy
| | - A Parmagnani
- University of Padova Department of Biomedical Sciences Via Marzolo 3 35100 Padova Italy
| | - A Paoli
- University of Padova Department of Biomedical Sciences Via Marzolo 3 35100 Padova Italy
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Goyaram V, Kohn TA, Ojuka EO. Suppression of the GLUT4 adaptive response to exercise in fructose-fed rats. Am J Physiol Endocrinol Metab 2014; 306:E275-83. [PMID: 24326422 PMCID: PMC3920014 DOI: 10.1152/ajpendo.00342.2013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Exercise-induced increase in skeletal muscle GLUT4 expression is associated with hyperacetylation of histone H3 within a 350-bp DNA region surrounding the myocyte enhancer factor 2 (MEF2) element on the Glut4 promoter and increased binding of MEF2A. Previous studies have hypothesized that the increase in MEF2A binding is a result of improved accessibility of this DNA segment. Here, we investigated the impact of fructose consumption on exercise-induced GLUT4 adaptive response and directly measured the accessibility of the above segment to nucleases. Male Wistar rats (n = 30) were fed standard chow or chow + 10% fructose or maltodextrin drinks ad libitum for 13 days. In the last 6 days five animals per group performed 3 × 17-min bouts of intermittent swimming daily and five remained untrained. Triceps muscles were harvested and used to measure 1) GLUT4, pAMPK, and HDAC5 contents by Western blot, 2) accessibility of the DNA segment from intact nuclei using nuclease accessibility assays, 3) acetylation level of histone H3 and bound MEF2A by ChIP assays, and 4) glycogen content. Swim training increased GLUT4 content by ∼66% (P < 0.05) but fructose and maltodextrin feeding suppressed the adaptation. Accessibility of the DNA region to MNase and DNase I was significantly increased by swimming (∼2.75- and 5.75-fold, respectively) but was also suppressed in trained rats that consumed fructose or maltodextrin. Histone H3 acetylation and MEF2A binding paralleled the accessibility pattern. These findings indicate that both fructose and maltodextrin modulate the GLUT4 adaptive response to exercise by mechanisms involving chromatin remodeling at the Glut4 promoter.
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Affiliation(s)
- Veeraj Goyaram
- University of Capetown/Medical Research Center, Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town, Cape Town, South Africa
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35
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Rosenkilde M, Reichkendler MH, Auerbach P, Bonne TC, Sjödin A, Ploug T, Stallknecht BM. Changes in peak fat oxidation in response to different doses of endurance training. Scand J Med Sci Sports 2013; 25:41-52. [PMID: 24350597 DOI: 10.1111/sms.12151] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/14/2013] [Indexed: 11/29/2022]
Abstract
The effect of different doses of endurance training on the capacity to oxidize fat during exercise in sedentary, overweight men and assessment of variables associated with changes in peak fat oxidation (PFO) were evaluated. Young, sedentary, overweight men were randomized to either the high-dose (HIGH, 600 kcal/day, n = 17) or moderate-dose (MOD, 300 kcal/day, n = 18) endurance training groups or controls (CON, n = 15). PFO and peak oxygen uptake (VO2 peak) were measured using indirect calorimetry, body composition using dual-energy x-ray absorptiometry, and protein levels of mitochondrial enzymes determined by Western blotting. PFO increased in both MOD [1.2 mg/kg fat-free mass (FFM)/min, 95% confidence interval (CI): 0.08:2.3, P = 0.03] and HIGH (1.8 mg/kg FFM/min, CI: 0.6:2.9, P < 0.001) compared with CON. Skeletal muscle expression of citrate synthase, β-hydroxyacyl-CoA dehydrogenase, and mitochondrial oxphos complexes II-V increased similarly in MOD and HIGH. Stepwise multiple linear regression analysis with backward elimination of individual variables correlated with changes in PFO revealed increases in cycling efficiency, FFM, and VO2 peak as the remaining associated variables. In conclusion, PFO during exercise increased with both moderate- and high-dose endurance training. Increases in PFO were mainly predicted by changes in VO2 peak, FFM, and cycling efficiency, and less with skeletal muscle mitochondrial enzymes.
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Affiliation(s)
- M Rosenkilde
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
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36
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Influence of lipolysis and fatty acid availability on fuel selection during exercise. J Physiol Biochem 2013; 70:583-91. [PMID: 24338384 DOI: 10.1007/s13105-013-0306-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 12/02/2013] [Indexed: 01/26/2023]
Abstract
The aim of the present study was to investigate the influence of substrate availability on fuel selection during exercise. Eight endurance-trained male cyclists performed 90-min exercise at 70% of their maximal oxygen uptake in a cross-over design, either in rested condition (CON) or the day after 2-h exercise practised at 70% of maximal oxygen uptake (EX). Subjects were given a sucrose load (0.75 g kg(-1) body weight) 45 min after the beginning of the 90-min exercise test. Lipolysis was measured in subcutaneous abdominal adipose tissue (SCAT) by microdialysis and substrate oxidation by indirect calorimetry. Lipid oxidation increased during exercise and tended to decrease during sucrose ingestion in both conditions. Lipid oxidation was higher during the whole experimental period in the EX group (p = 0.004). Interestingly, fuel selection, assessed by the change in respiratory exchange ratio (RER), was increased in the EX session (p = 0.002). This was paralleled by a higher rate of SCAT lipolysis reflected by dialysate glycerol, plasma glycerol, and fatty acids (FA) levels (p < 0.001). Of note, we observed a significant relationship between whole-body fat oxidation and dialysate glycerol in both sessions (r (2) = 0.33, p = 0.02). In conclusion, this study highlights the limiting role of lipolysis and plasma FA availability to whole-body fat oxidation during exercise in endurance-trained subjects. This study shows that adipose tissue lipolysis is a determinant of fuel selection during exercise in healthy subjects.
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Ashrafian H, Li JV, Spagou K, Harling L, Masson P, Darzi A, Nicholson JK, Holmes E, Athanasiou T. Bariatric surgery modulates circulating and cardiac metabolites. J Proteome Res 2013; 13:570-80. [PMID: 24279706 DOI: 10.1021/pr400748f] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Bariatric procedures such as the Roux-en-Y gastric bypass (RYGB) operation offer profound metabolic enhancement in addition to their well-recognized weight loss effects. They are associated with significant reduction in cardiovascular disease risk and mortality, which suggests a surgical modification on cardiac metabolism. Metabolic phenotyping of the cardiac tissue and plasma postsurgery may give insight into cardioprotective mechanisms. The aim of the study was to compare the metabolic profiles of plasma and heart tissue extracts from RYGB- and sham-operated Wistar rats to identify the systemic and cardiac signature of metabolic surgery. A total of 27 male Wistar rats were housed individually for a week and subsequently underwent RYGB (n = 13) or sham (n = 14) operation. At week 8 postoperation, a total of 27 plasma samples and 16 heart tissue samples (8 RYGB; 8 Sham) were collected from animals and analyzed using (1)H nuclear magnetic resonance (NMR) spectroscopy and ultra performance liquid chromatography (UPLC-MS) to characterize the global metabolite perturbation induced by RYGB operation. Plasma bile acids, phosphocholines, amino acids, energy-related metabolites, nucleosides and amine metabolites, and cardiac glycogen and amino acids were found to be altered in the RYGB operated group. Correlation networks were used to identify metabolite association. The metabolic phenotype of this bariatric surgical model inferred systematic change in both myocardial and systemic activity post surgery. The altered metabolic profile following bariatric surgery reflects an enhancement of cardiac energy metabolism through TCA cycle intermediates, cardiorenal protective activity, and biochemical caloric restriction. These surgically induced metabolic shifts identify some of the potential mechanisms that contribute toward bariatric cardioprotection through gut microbiota ecological fluxes and an enterocardiac axis to shield against metabolic syndrome of cardiac dysfunction.
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Affiliation(s)
- Hutan Ashrafian
- Department of Surgery and Cancer, Faculty of Medicine, Imperial College London , SW11 2PH London, U.K
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Aziz AR, Png W, Che Muhamed AM, Chaouachi A, Chong E, Singh R. Effects of Ramadan fasting on substrate oxidation, physiological and perceptual responses during submaximal intensity running in active men. SPORT SCIENCES FOR HEALTH 2013. [DOI: 10.1007/s11332-013-0163-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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E Nico ETM, de Oliveira PR, de Souza LP, Pereira FDC, Delbin MA, Zanesco A, Camargo-Mathias MI. The action of aminoguanidine on the liver of trained diabetic rats. J Diabetes Metab Disord 2013; 12:40. [PMID: 23837632 PMCID: PMC7983740 DOI: 10.1186/2251-6581-12-40] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Accepted: 07/06/2013] [Indexed: 01/11/2023]
Abstract
Background This study evaluated the effect of aminoguanidine on liver of diabetic rats subject to physical exercises using histological and histochemical techniques. Methods The rats used in this study were divided into five groups: sedentary control, sedentary diabetic, trained diabetic, sedentary diabetic and treated with aminoguanidine, trained diabetic and treated with aminoguanidine. Results The results showed no effect of aminoguanidine on the liver tissue, although there was improvement with exercise training showing cytological, morpho-histological and histochemical alterations in liver cells of animals from groups trained diabetic and/or treated diabetic compared to those individuals in the sedentary control and sedentary diabetic. These changes included: hepatocytes hypertrophy, presence and distribution of polysaccharides in the hepatocytes cytoplasm and, especially, congestion of the liver blood vessels. Conclusion Our results suggest that aminoguanidine is not hepatotoxic, when used at dosage of 1 g/L for the treatment of diabetes complications, and confirmed that the practice of moderate physical exercise assuaged the damage caused by diabetes without the use of insulin. Electronic supplementary material The online version of this article (doi:10.1186/2251-6581-12-40) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | - Leonardo Peres de Souza
- UNESP-University Estadual Paulista, Avenida 24 A, 1515, 13506-900, Rio Claro, SP CP 199, Brazil
| | | | - Maria Andréia Delbin
- UNESP-University Estadual Paulista, Avenida 24 A, 1515, 13506-900, Rio Claro, SP CP 199, Brazil
| | - Angelina Zanesco
- UNESP-University Estadual Paulista, Avenida 24 A, 1515, 13506-900, Rio Claro, SP CP 199, Brazil
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Geat M, Stel G, Poser S, Driussi C, Stenner E, Francescato MP. Whole-body glucose oxidation rate during prolonged exercise in type 1 diabetic patients under usual life conditions. Metabolism 2013; 62:836-44. [PMID: 23375550 DOI: 10.1016/j.metabol.2013.01.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 12/27/2012] [Accepted: 01/01/2013] [Indexed: 01/08/2023]
Abstract
OBJECTIVE Fuel oxidation during exercise was studied in type 1 insulin-dependent (T1DM) patients mainly under quite constant insulin and glycemia; these protocols, however, likely do not reflect patients' usual metabolic conditions. The glucose oxidation rate (GLUox) in T1DM patients under usual life conditions was thus investigated during prolonged exercise (3-h) and its behavior was described mathematically. MATERIALS/METHODS Whole-body GLUox was determined in eight T1DM patients (4/8 M; aged 35-59 years) and eight well-matched healthy subjects. Venous blood was drawn prior to and every 30 min until the end of exercise; glycemia, insulin, cortisol, and growth hormone concentrations were determined. Oxygen consumption, carbon dioxide production, and ventilation were measured at rest and thereafter every 30 min of the exercise. To prevent hypoglycemia, patients were given fruit fudge (93% sucrose) prior to / during exercise. RESULTS Insulin concentration and glycemia were significantly higher in patients across the entire exercise period (group effect, p<0.001 for both). GLUox decreased significantly with increasing exercise duration (time effect, p<0.001), but no significant difference was detected between the two groups (group effect, p=NS). GLUox, expressed as the percentage of the starting value, was described by an exponential function showing a time constant of 90 min (n=96; mean corrected R(2)=0.666). CONCLUSIONS GLUox in T1DM patients was not significantly different from the rate observed in the control subjects. The function describing the time course of GLUox may be useful to correct an estimated GLUox for the duration of exercise and help T1DM patients avoiding exercise-induced glycemic imbalances.
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Affiliation(s)
- Mario Geat
- Department of Medical and Biological Sciences, University of Udine, 33100-Udine, Italy
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Chenevière X, Borrani F, Droz D, Gojanovic B, Malatesta D. Effects of 2 different prior endurance exercises on whole-body fat oxidation kinetics: light vs. heavy exercise. Appl Physiol Nutr Metab 2012; 37:955-64. [DOI: 10.1139/h2012-076] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study aimed to compare the effects of 2 different prior endurance exercises on subsequent whole-body fat oxidation kinetics. Fifteen men performed 2 identical submaximal incremental tests (Incr2) on a cycle ergometer after (i) a ∼40-min submaximal incremental test (Incr1) followed by a 90-min continuous exercise performed at 50% of maximal aerobic power-output and a 1-h rest period (Heavy); and (ii) Incr1 followed by a 2.5-h rest period (Light). Fat oxidation was measured using indirect calorimetry and plotted as a function of exercise intensity during Incr1 and Incr2. A sinusoidal equation, including 3 independent variables (dilatation, symmetry and translation), was used to characterize the fat oxidation kinetics and to determine the intensity (Fatmax) that elicited the maximal fat oxidation (MFO) during Incr. After the Heavy and Light trials, Fatmax, MFO, and fat oxidation rates were significantly greater during Incr2 than Incr1 (p < 0.001). However, Δ (i.e., Incr2–Incr1) Fatmax, MFO, and fat oxidation rates were greater in the Heavy compared with the Light trial (p < 0.05). The fat oxidation kinetics during Incr2Heavy showed a greater dilatation and rightward asymmetry than Incr1Heavy, whereas only a greater dilatation was observed in Incr2Light (p < 0.05). This study showed that although to a lesser extent in the Light trial, both prior exercise sessions led to an increase in Fatmax, MFO, and absolute fat oxidation rates during Incr2, inducing significant changes in the shape of the fat oxidation kinetics.
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Affiliation(s)
- Xavier Chenevière
- Institute of Sport Sciences (ISSUL), Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Bâtiment de Vidy, 1015 Lausanne, Switzerland
| | - Fabio Borrani
- Institute of Sport Sciences (ISSUL), Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Bâtiment de Vidy, 1015 Lausanne, Switzerland
- Department of Sport and Exercise Science, University of Auckland, Auckland 1142, New Zealand
| | - David Droz
- Institute of Sport Sciences (ISSUL), Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Bâtiment de Vidy, 1015 Lausanne, Switzerland
| | - Boris Gojanovic
- Department of Locomotion, CHUV, Avenue Pierre Decker 4, 1011 Lausanne, Switzerland
| | - Davide Malatesta
- Institute of Sport Sciences (ISSUL), Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Bâtiment de Vidy, 1015 Lausanne, Switzerland
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Milutinović A, Zorc-Pleskovič R. Glycogen accumulation in cardiomyocytes and cardiotoxic effects after 3NPA treatment. Bosn J Basic Med Sci 2012; 12:15-9. [PMID: 22364298 DOI: 10.17305/bjbms.2012.2525] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Mitochondrial toxin 3-nitropropionic acid (3NPA) is a neurotoxin that inhibits the activity of succinate dehydrogenase, a key enzyme of oxidative energy production, and characteristically provokes neurodegeneration in the striatum, resembling Huntington's disease. 3NPA also affects the activity of glycogen-sinthase-kinase-3b (GSK-3b), an enzyme implicated in glycogen synthesis and in signal transduction. The aim of this study was to evaluate cardiac glycogen content and histopathological changes in the hearts of rats after subchronic treatment with 3NPA.Female adult Wistar rats were treated daily with 30mg/kg of 3NPA subcutaneously 8 days. The control group was treated with normal saline for 8 days. For the comparison of measured parameters between groups we used the Student's t-test (p<0.05). The stereological evaluation of glycogen content in histological sections of the heart was processed with periodic acid-Schiff (PAS). Histochemical procedure showed a significant accumulation of glycogen granules in the 3NPA group (0.028mm(3)/mm(3)±0.022), whereas the hearts of control animals were nearly devoid of glycogen granules (0.002mm(3)/mm(3)±0.001). Haematoxylin-eosin histological staining showed diffuse swelling of cardiomyocytes (3NPA=15.989μm ±1.649; saline=13.456μm ± 0.786), loss of cell cross-striations, lower myofibril volume fraction (3NPA=0.3922mm(3)/mm3 ± 0.0230, saline=0.4550mm(3)/mm3 ± 0.0083), and mononuclear infiltration in the interstitial tissue, mostly along the blood vessels. Sirius red staining showed fibrosis of the heart (3NPA=0.0531mm93)/mm(3)±0.0090, saline=0.0135mm(3)/mm3 ± 0.0051). TUNEL staining showed TUNEL-positive cells in the 3NPA group (2.04cells/mm2 ± 0.92) and almost no TUNEL-positive cells in the saline group (0.27cells/mm2 ± 0.14). This experiment shows that 3NPA-induced histopathological changes in the heart are accompanied by a significant accumulation of glycogen granules in cardiomyocytes.
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Affiliation(s)
- Aleksandra Milutinović
- University of Ljubljana, Medical Faculty, Institute of Histology and Embryology, Ljubljana, Slovenia.
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Rannou F, Leschiera R, Giroux-Metges MA, Pennec JP. Effects of lactate on the voltage-gated sodium channels of rat skeletal muscle: modulating current opinion. J Appl Physiol (1985) 2012; 112:1454-65. [DOI: 10.1152/japplphysiol.00944.2011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
During muscle contraction, lactate production and translocation across the membrane increase. While it has recently been shown that lactate anion acts on chloride channel, less is known regarding a potential effect on the voltage-gated sodium channel (Nav) of skeletal muscle. The electrophysiological properties of muscle Nav were studied in the absence and presence of lactate (10 mM) by using the macropatch-clamp method in dissociated fibers from rat peroneus longus (PL). Lactate in the external medium (petri dish + pipette) increases the maximal sodium current, while the voltage dependence of activation and fast inactivation are shifted toward the hyperpolarized potentials. Lactate induces a leftward shift in the relationship between the kinetic parameters and the imposed potentials, resulting in an earlier recruitment of muscle Nav. In addition, lactate significantly decreases the time constant of activation at voltages more negative than −10 mV, corresponding to an acceleration of Nav activation. The slow inactivation process is decreased by lactate, corresponding to an enhancement in the number of excitable Nav. In an additional series of experiments, lactate (10 mM) was only added to the petri dish, while the pipette remained sealed on the membrane area. With this approach, the electrophysiological properties of Nav were unaffected by lactate compared with the control condition. Altogether, these data indicate that lactate modulates muscle Nav properties by an extracellular pathway. These effects are consistent with an enhancement in excitability, providing new insights into the role of lactate in muscle physiology.
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Affiliation(s)
- F. Rannou
- Université de Brest, Faculté de Médecine et des Sciences de la Santé, EA 1274-M2S, Laboratoire de Physiologie
- CHU Brest, Service d'Explorations Fonctionnelles Respiratoires; and
- Université Européenne de Bretagne, Brest, France
| | - R. Leschiera
- Université de Brest, Faculté de Médecine et des Sciences de la Santé, EA 1274-M2S, Laboratoire de Physiologie
- Université Européenne de Bretagne, Brest, France
| | - M. A. Giroux-Metges
- Université de Brest, Faculté de Médecine et des Sciences de la Santé, EA 1274-M2S, Laboratoire de Physiologie
- CHU Brest, Service d'Explorations Fonctionnelles Respiratoires; and
- Université Européenne de Bretagne, Brest, France
| | - J. P. Pennec
- Université de Brest, Faculté de Médecine et des Sciences de la Santé, EA 1274-M2S, Laboratoire de Physiologie
- Université Européenne de Bretagne, Brest, France
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Hawley JA, Burke LM, Phillips SM, Spriet LL. Nutritional modulation of training-induced skeletal muscle adaptations. J Appl Physiol (1985) 2011; 110:834-45. [DOI: 10.1152/japplphysiol.00949.2010] [Citation(s) in RCA: 139] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Skeletal muscle displays remarkable plasticity, enabling substantial adaptive modifications in its metabolic potential and functional characteristics in response to external stimuli such as mechanical loading and nutrient availability. Contraction-induced adaptations are determined largely by the mode of exercise and the volume, intensity, and frequency of the training stimulus. However, evidence is accumulating that nutrient availability serves as a potent modulator of many acute responses and chronic adaptations to both endurance and resistance exercise. Changes in macronutrient intake rapidly alter the concentration of blood-borne substrates and hormones, causing marked perturbations in the storage profile of skeletal muscle and other insulin-sensitive tissues. In turn, muscle energy status exerts profound effects on resting fuel metabolism and patterns of fuel utilization during exercise as well as acute regulatory processes underlying gene expression and cell signaling. As such, these nutrient-exercise interactions have the potential to activate or inhibit many biochemical pathways with putative roles in training adaptation. This review provides a contemporary perspective of our understanding of the molecular and cellular events that take place in skeletal muscle in response to both endurance and resistance exercise commenced after acute and/or chronic alterations in nutrient availability (carbohydrate, fat, protein, and several antioxidants). Emphasis is on the results of human studies and how nutrient provision (or lack thereof) interacts with specific contractile stimulus to modulate many of the acute responses to exercise, thereby potentially promoting or inhibiting subsequent training adaptation.
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Affiliation(s)
- John A. Hawley
- Health Innovations Research Institute, School of Medical Sciences, RMIT University, Bundoora, Australia
| | - Louise M. Burke
- Department of Sports Nutrition, Australian Institute of Sport, Belconnen, Australia
| | | | - Lawrence L. Spriet
- Department of Human Health and Nutritional Sciences, College of Biological Sciences, University of Guelph, Guelph, Ontario, Canada
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ROLLO IAN, WILLIAMS CLYDE, NEVILL MARY. Influence of Ingesting versus Mouth Rinsing a Carbohydrate Solution during a 1-h Run. Med Sci Sports Exerc 2011; 43:468-75. [DOI: 10.1249/mss.0b013e3181f1cda3] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Berman Y, North KN. A gene for speed: the emerging role of alpha-actinin-3 in muscle metabolism. Physiology (Bethesda) 2010; 25:250-9. [PMID: 20699471 DOI: 10.1152/physiol.00008.2010] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A common polymorphism (R577X) in the ACTN3 gene results in complete deficiency of alpha-actinin-3 protein in approximately 16% of humans worldwide. The presence of alpha-actinin-3 protein is associated with improved sprint/power performance in athletes and the general population. Despite this, there is evidence that the null genotype XX has been acted on by recent positive selection, likely due to its emerging role in the regulation of muscle metabolism. alpha-Actinin-3 deficiency reduces the activity of glycogen phosphorylase and results in a fundamental shift toward more oxidative pathways of energy utilization.
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Affiliation(s)
- Yemima Berman
- Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Westmead, Australia
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Metabolic factors limiting performance in marathon runners. PLoS Comput Biol 2010; 6:e1000960. [PMID: 20975938 PMCID: PMC2958805 DOI: 10.1371/journal.pcbi.1000960] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Accepted: 09/17/2010] [Indexed: 11/19/2022] Open
Abstract
Each year in the past three decades has seen hundreds of thousands of runners register to run a major marathon. Of those who attempt to race over the marathon distance of 26 miles and 385 yards (42.195 kilometers), more than two-fifths experience severe and performance-limiting depletion of physiologic carbohydrate reserves (a phenomenon known as ‘hitting the wall’), and thousands drop out before reaching the finish lines (approximately 1–2% of those who start). Analyses of endurance physiology have often either used coarse approximations to suggest that human glycogen reserves are insufficient to fuel a marathon (making ‘hitting the wall’ seem inevitable), or implied that maximal glycogen loading is required in order to complete a marathon without ‘hitting the wall.’ The present computational study demonstrates that the energetic constraints on endurance runners are more subtle, and depend on several physiologic variables including the muscle mass distribution, liver and muscle glycogen densities, and running speed (exercise intensity as a fraction of aerobic capacity) of individual runners, in personalized but nevertheless quantifiable and predictable ways. The analytic approach presented here is used to estimate the distance at which runners will exhaust their glycogen stores as a function of running intensity. In so doing it also provides a basis for guidelines ensuring the safety and optimizing the performance of endurance runners, both by setting personally appropriate paces and by prescribing midrace fueling requirements for avoiding ‘the wall.’ The present analysis also sheds physiologically principled light on important standards in marathon running that until now have remained empirically defined: The qualifying times for the Boston Marathon. Marathon running, historically perceived as testing the physiologic limits of human endurance, has become increasingly popular even among recreational runners. Of those runners who test their endurance by racing the marathon distance, however, more than two in five report ‘hitting the wall,’ the rapid onset of severe fatigue and inability to maintain a high-intensity pace, resulting from the near-complete depletion of carbohydrate stores in the leg muscles and liver. An apparent paradox of long-distance running is that even the leanest athletes store enough fat to power back-to-back marathons, yet small carbohydrate reservoirs can nevertheless catastrophically limit performance in endurance exercise. In this study I develop and validate a mathematical model that facilitates computation of personalized estimates of the distances at which runners will exhaust their carbohydrate stores while running at selected paces. In addition, I provide a systematic approach to estimating personalized maximum speeds at which runners can safely complete a marathon, based on accessible physiologic parameters such as heart rate and running speed. This analysis provides a quantitative basis for improving the safety and optimizing the performance of endurance runners, evaluating midrace fueling requirements, and estimating limits of performance in human endurance running, for elite and recreational runners alike.
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Hamzah S, Higgins S, Abraham T, Taylor P, Vizbaraite D, Malkova D. The effect of glycaemic index of high carbohydrate diets consumed over 5 days on exercise energy metabolism and running capacity in males. J Sports Sci 2009; 27:1545-54. [DOI: 10.1080/02640410903134115] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Giesel VT, Reche M, Schneider L, Araújo LC, Scalco R, von Eye Corleta H, Capp E. Effects of intermittent high-intensity exercise and carbohydrate supplementation on IGF-1 and glycogen of Wistar rats. Growth Horm IGF Res 2009; 19:156-161. [PMID: 18835207 DOI: 10.1016/j.ghir.2008.08.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2008] [Revised: 08/20/2008] [Accepted: 08/21/2008] [Indexed: 11/27/2022]
Abstract
OBJECTIVE The aim of this study was to analyze the association between glucose infusion during intermittent physical exercise and its metabolic effects on rats. DESIGN Forty male rats were divided into eight groups based on training (intermittent), exercise and carbohydrate intake (glucose 20%): TEC (trained exercised with carbohydrate), TES (trained exercised without carbohydrate), TNC (trained non-exercised with carbohydrate), TNS (trained non-exercised without carbohydrate), UEC (untrained exercised with carbohydrate), UES (untrained exercised without carbohydrate), UNC (untrained non-exercised with carbohydrate) and UNS (untrained non-exercised without carbohydrate). The training and/or exercise protocol consisted of the rats running on a treadmill for 1 min above the lactate threshold, or running below the lactate threshold for 30s, intermittently for 30 min. Blood was analyzed for glycemia, lactate and IGF-1. Muscle and liver glycogen were measured (T2). RESULTS Glycemia was found to be different in T2 compared to T1 in the TEC, TNC, UEC and UNC groups. Lactate was higher in T2 than in T1, but remained within the lactate threshold. Glycogen showed higher concentrations in the trained groups and, whether trained or not, in the supplemented groups. IGF-1 levels were higher in exercised rats independent of supplementation or glycogen levels. Trained rats showed lower IGF-1 when exercising than did the untrained animals. CONCLUSIONS We conclude that intermittent exercise is beneficial in preventing a trained lactate pool, and that, in association with glucose supplementation, intermittent exercise will be efficient both in preventing a trained lactate pool and in maintaining sufficient glycemia levels. Exercise raises IGF-1 levels, whereas training inverts this relationship.
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Affiliation(s)
- Vivian Treichel Giesel
- Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
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Vol A, Gribova O, Berman S, Siman-Tov Y, Efrati S. Application of muscle biopotential measurement for sustained, noninvasive blood glucose survey. J Appl Physiol (1985) 2009; 107:253-60. [PMID: 19265065 DOI: 10.1152/japplphysiol.90960.2008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Biopotential, the electric potential generated by living tissues, is affected by changes in extracellular electrolyte and glucose concentrations. We aimed to apply correlation between blood glucose concentrations (BGC) and biopotential of peripheral muscles for noninvasive blood glucose measurement. The study included 58 Wistar rats. In part of them, diabetes was induced by streptozotocin injection. Group 1, comprising 19 normal and 5 diabetic rats, received glucose-challenging protocol (intraperitoneal injection of 1 g/ml glucose). Group 2, 24 normal and 6 diabetic rats, received insulin-challenging protocol (three 30 IU insulin injections with 15-min intervals). Four control rats, group 3, were injected with 2-ml saline. BGC were measured by a standard ACCU-CHEK-Sensor Meter and compared with those estimated by biopotential sensor, further designated as GlucoSat, placed around proximal parts of the tails of the anaesthetized animals. GlucoSat results were calculated using the following biopotential equation: BGC(t) = k1 F1(t) + k2 F2(t) k3 F3(t) + k4, based on an experimental model involving estimation of pH, muscle metabolism, and tissue conductance, where t is time, k1-k4 are coefficients, and F1-F4 are functions. Mean biopotential system measured BGC was 181.7 +/- 4.3 mg/dl, not differing statistically from 187.9 +/- 4.3 mg/dl estimated by ACCU-CHEK. Pearson's correlation coefficient (r(2)) was 0.961 (P < 0.00001), indicating strong, direct correlation between the results. Within the nondiabetic group, r(2) was 0.944 (P < 0.00001), while, within the diabetic group, r(2) was 0.974 (P < 0.00001). No significant, adverse skin reactions were concomitantly observed in any experimental group. Biopotential measurements may be used for continuous, noninvasive estimation of changes in BGC. Further studies are needed to evaluate the applicability of this method to humans.
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Affiliation(s)
- Alexander Vol
- Research and Development Unit, Assaf Harofeh Medical Center, Zerifin, Affiliated to Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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