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Coffee Increases Post-Exercise Muscle Glycogen Recovery in Endurance Athletes: A Randomized Clinical Trial.
Loureiro, LMR, Dos Santos Neto, E, Molina, GE, Amato, AA, Arruda, SF, Reis, CEG, da Costa, THM
Nutrients. 2021;(10)
Abstract
Coffee is one of the most widely consumed beverages worldwide and caffeine is known to improve performance in physical exercise. Some substances in coffee have a positive effect on glucose metabolism and are promising for post-exercise muscle glycogen recovery. We investigated the effect of a coffee beverage after exhaustive exercise on muscle glycogen resynthesis, glycogen synthase activity and glycemic and insulinemic response in a double-blind, crossover, randomized clinical trial. Fourteen endurance-trained men performed an exhaustive cycle ergometer exercise to deplete muscle glycogen. The following morning, participants completed a second cycling protocol followed by a 4-h recovery, during which they received either test beverage (coffee + milk) or control (milk) and a breakfast meal, with a simple randomization. Blood samples and muscle biopsies were collected at the beginning and by the end of recovery. Eleven participants were included in data analysis (age: 39.0 ± 6.0 years; BMI: 24.0 ± 2.3 kg/m2; VO2max: 59.9 ± 8.3 mL·kg-1·min-1; PPO: 346 ± 39 W). The consumption of coffee + milk resulted in greater muscle glycogen recovery (102.56 ± 18.75 vs. 40.54 ± 18.74 mmol·kg dw-1; p = 0.01; d = 0.94) and greater glucose (p = 0.02; d = 0.83) and insulin (p = 0.03; d = 0.76) total area under the curve compared with control. The addition of coffee to a beverage with adequate amounts of carbohydrates increased muscle glycogen resynthesis and the glycemic and insulinemic response during the 4-h recovery after exhaustive cycling exercise.
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Carbohydrate mouth rinse improves resistance exercise capacity in the glycogen-lowered state.
Durkin, M, Akeroyd, H, Holliday, A
Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme. 2021;(2):126-132
Abstract
The effect of carbohydrate mouth rinse (CHO MR) on resistance exercise performance is equivocal and may be moderated by carbohydrate availability. This study determined the effect of CHO MR on low-load resistance exercise capacity completed in a fed but glycogen-lowered state. Twelve resistance-trained men (age: 22 ± 4 years; height: 1.79 ± 0.05 m; mass: 78.7 ± 7.8 kg; bench press one-repetition maximum (1RM): 87 ± 21 kg; squat 1RM: 123 ± 19 kg) completed two fed-state resistance exercise bouts consisting of six sets of bench press and six sets of squat to failure at 40% 1RM. Each bout was preceded by glycogen-depleting cycling the evening before, with feeding controlled to create acute energy deficit and maintain low muscle glycogen. During resistance exercise, participants rinsed with either a 6% CHO MR solution or a taste-matched placebo (PLA) between sets. Total volume workload was greater with CHO MR (9354 ± 2051 vs. 8525 ± 1911 kg, p = 0.010). Total number of repetitions of squat were greater with CHO MR (107 ± 26 vs. 92 ± 16, p = 0.017); the number of repetitions of bench press were not significantly different (CHO MR 120 ± 24 vs. PLA: 115 ± 22, p = 0.146). This was independent of differences in feeling or arousal. CHO MR may be an effective ergogenic aid for athletes completing resistance exercise when in energy deficit and with low carbohydrate availability. Novelty: CHO MR can increase low-load resistance exercise capacity undertaken in a glycogen-lowered but fed state. This effect was driven by a greater number of repetitions-to-failure in the squat - using muscles lowered in glycogen content with exhaustive cycling on the evening prior to resistance exercise - but not bench press.
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Muscle Glycogen Utilization during Exercise after Ingestion of Alcohol.
Smith, HA, Hengist, A, Bonson, DJ, Walhin, JP, Jones, R, Tsintzas, K, Afman, GH, Gonzalez, JT, Betts, JA
Medicine and science in sports and exercise. 2021;(1):211-217
Abstract
PURPOSE Ingested ethanol (EtOH) is metabolized gastrically and hepatically, which may influence resting and exercise metabolism. Previous exercise studies have provided EtOH intravenously rather than orally, altering the metabolic effects of EtOH. No studies to date have investigated the effects of EtOH ingestion on systemic and peripheral (e.g., skeletal muscle) exercise metabolism. METHODS Eight men (mean ± SD; age = 24 ± 5 yr, body mass = 76.7 ± 5.6 kg, height = 1.80 ± 0.04 m, V˙O2peak = 4.1 ± 0.2 L·min) performed two bouts of fasted cycling exercise at 55% V˙O2peak for 2 h, with (EtOH) and without (control) prior ingestion of EtOH 1 h and immediately before exercise (total dose = 0.1 g·kg lean body mass·h; 30.2 ± 1.1 g 40% ABV Vodka; fed in two equal boluses) in a randomized order, separated by 7-10 d. RESULTS Muscle glycogen use during exercise was not different between conditions (mean [normalized 95% confidence interval]; EtOH, 229 [156-302] mmol·kg dm, vs control, 258 [185-331] mmol·kg dm; P = 0.67). Mean plasma glucose concentrations during exercise were similar (control, 5.26 [5.22-5.30], vs EtOH, 5.34 [5.30-5.38]; P = 0.06). EtOH ingestion resulted in similar plasma nonesterified fatty acid concentrations compared with rest (control, 0.43 [0.31-0.55] mmol·L, vs EtOH, 0.30 [0.21-0.40] mmol·L) and during exercise. Plasma lactate concentration was higher during the first 30 min of rest after EtOH consumption (mean concentration; control, 0.83 [0.77-0.90] mmol·L, vs EtOH, 1.00 [0.93-1.07] mmol·L), but the response during exercise was similar between conditions. CONCLUSIONS Muscle glycogen utilization was similar during exercise with or without prior EtOH ingestion, reflected in similar total whole-body carbohydrate oxidation rates observed.
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Coingestion of Carbohydrate and Protein on Muscle Glycogen Synthesis after Exercise: A Meta-analysis.
Margolis, LM, Allen, JT, Hatch-McChesney, A, Pasiakos, SM
Medicine and science in sports and exercise. 2021;(2):384-393
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Abstract
INTRODUCTION/PURPOSE Evidence suggests that carbohydrate and protein (CHO-PRO) ingestion after exercise enhances muscle glycogen repletion to a greater extent than carbohydrate (CHO) alone. However, there is no consensus at this point, and results across studies are mixed, which may be attributable to differences in energy content and carbohydrate intake relative to body mass consumed after exercise. The purpose of this study was determine the overall effects of CHO-PRO and the independent effects of energy and relative carbohydrate content of CHO-PRO supplementation on postexercise muscle glycogen synthesis compared with CHO alone. METHODS Meta-analysis was conducted on crossover studies assessing the influence of CHO-PRO compared with CHO alone on postexercise muscle glycogen synthesis. Studies were identified in a systematic review from PubMed and Cochrane Library databases. Data are presented as effect size (95% confidence interval [CI]) using Hedges' g. Subgroup analyses were conducted to evaluate effects of isocaloric and nonisocaloric energy content and dichotomized by median relative carbohydrate (high, ≥0.8 g·kg-1⋅h-1; low, <0.8 g·kg-1⋅h-1) content on glycogen synthesis. RESULTS Twenty studies were included in the analysis. CHO-PRO had no overall effect on glycogen synthesis (0.13, 95% CI = -0.04 to 0.29) compared with CHO. Subgroup analysis found that CHO-PRO had a positive effect (0.26, 95% CI = 0.04-0.49) on glycogen synthesis when the combined intervention provided more energy than CHO. Glycogen synthesis was not significant (-0.05, 95% CI = -0.23 to 0.13) in CHO-PRO compared with CON when matched for energy content. There was no statistical difference of CHO-PRO on glycogen synthesis in high (0.07, 95% CI = -0.11 to 0.22) or low (0.21, 95% CI = -0.08 to 0.50) carbohydrate content compared with CHO. CONCLUSION Glycogen synthesis rates are enhanced when CHO-PRO are coingested after exercise compared with CHO only when the added energy of protein is consumed in addition to, not in place of, carbohydrate.
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The Validity of Ultrasound Technology in Providing an Indirect Estimate of Muscle Glycogen Concentrations Is Equivocal.
Bone, JL, Ross, ML, Tomcik, KA, Jeacocke, NA, McKay, AKA, Burke, LM
Nutrients. 2021;(7)
Abstract
Researchers and practitioners in sports nutrition would greatly benefit from a rapid, portable, and non-invasive technique to measure muscle glycogen, both in the laboratory and field. This explains the interest in MuscleSound®, the first commercial system to use high-frequency ultrasound technology and image analysis from patented cloud-based software to estimate muscle glycogen content from the echogenicity of the ultrasound image. This technique is based largely on muscle water content, which is presumed to act as a proxy for glycogen. Despite the promise of early validation studies, newer studies from independent groups reported discrepant results, with MuscleSound® scores failing to correlate with the glycogen content of biopsy-derived mixed muscle samples or to show the expected changes in muscle glycogen associated with various diet and exercise strategies. The explanation of issues related to the site of assessment do not account for these discrepancies, and there are substantial problems with the premise that the ratio of glycogen to water in the muscle is constant. Although further studies investigating this technique are warranted, current evidence that MuscleSound® technology can provide valid and actionable information around muscle glycogen stores is at best equivocal.
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Targeted Therapies for Metabolic Myopathies Related to Glycogen Storage and Lipid Metabolism: a Systematic Review and Steps Towards a 'Treatabolome'.
Manta, A, Spendiff, S, Lochmüller, H, Thompson, R
Journal of neuromuscular diseases. 2021;(3):401-417
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BACKGROUND Metabolic myopathies are a heterogenous group of muscle diseases typically characterized by exercise intolerance, myalgia and progressive muscle weakness. Effective treatments for some of these diseases are available, but while our understanding of the pathogenesis of metabolic myopathies related to glycogen storage, lipid metabolism and β-oxidation is well established, evidence linking treatments with the precise causative genetic defect is lacking. OBJECTIVE The objective of this study was to collate all published evidence on pharmacological therapies for the aforementioned metabolic myopathies and link this to the genetic mutation in a format amenable to databasing for further computational use in line with the principles of the "treatabolome" project. METHODS A systematic literature review was conducted to retrieve all levels of evidence examining the therapeutic efficacy of pharmacological treatments on metabolic myopathies related to glycogen storage and lipid metabolism. A key inclusion criterion was the availability of the genetic variant of the treated patients in order to link treatment outcome with the genetic defect. RESULTS Of the 1,085 articles initially identified, 268 full-text articles were assessed for eligibility, of which 87 were carried over into the final data extraction. The most studied metabolic myopathies were Pompe disease (45 articles), multiple acyl-CoA dehydrogenase deficiency related to mutations in the ETFDH gene (15 articles) and systemic primary carnitine deficiency (8 articles). The most studied therapeutic management strategies for these diseases were enzyme replacement therapy, riboflavin, and carnitine supplementation, respectively. CONCLUSIONS This systematic review provides evidence for treatments of metabolic myopathies linked with the genetic defect in a computationally accessible format suitable for databasing in the treatabolome system, which will enable clinicians to acquire evidence on appropriate therapeutic options for their patient at the time of diagnosis.
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The potential of dietary treatment in patients with glycogen storage disease type IV.
Derks, TGJ, Peeks, F, de Boer, F, Fokkert-Wilts, M, van der Doef, HPJ, van den Heuvel, MC, Szymańska, E, Rokicki, D, Ryan, PT, Weinstein, DA
Journal of inherited metabolic disease. 2021;(3):693-704
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Abstract
There is paucity of literature on dietary treatment in glycogen storage disease (GSD) type IV and formal guidelines are not available. Traditionally, liver transplantation was considered the only treatment option for GSD IV. In light of the success of dietary treatment for the other hepatic forms of GSD, we have initiated this observational study to assess the outcomes of medical diets, which limit the accumulation of glycogen. Clinical, dietary, laboratory, and imaging data for 15 GSD IV patients from three centres are presented. Medical diets may have the potential to delay or prevent liver transplantation, improve growth and normalize serum aminotransferases. Individual care plans aim to avoid both hyperglycaemia, hypoglycaemia and/or hyperketosis, to minimize glycogen accumulation and catabolism, respectively. Multidisciplinary monitoring includes balancing between traditional markers of metabolic control (ie, growth, liver size, serum aminotransferases, glucose homeostasis, lactate, and ketones), liver function (ie, synthesis, bile flow and detoxification of protein), and symptoms and signs of portal hypertension.
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Muscle Glycogen Content during Endurance Training under Low Energy Availability.
Kojima, C, Ishibashi, A, Tanabe, Y, Iwayama, K, Kamei, A, Takahashi, H, Goto, K
Medicine and science in sports and exercise. 2020;(1):187-195
Abstract
PURPOSE The present study investigated the effects of three consecutive days of endurance training under conditions of low energy availability (LEA) on the muscle glycogen content, muscle damage markers, endocrine regulation, and endurance capacity in male runners. METHODS Seven male long-distance runners (19.9 ± 1.1 yr, 175.6 ± 4.7 cm, 61.4 ± 5.3 kg, maximal oxygen uptake [V˙O2max]: 67.5 ± 4.3 mL·kg·min) completed two trials consisting of three consecutive days of endurance training under LEA (18.9 ± 1.9 kcal·kg FFM·d) or normal energy availability (NEA) (52.9 ± 5.0 kcal·kg FFM·d). The order of the two trials was randomized, with a 2-wk interval between trials. The endurance training consisted of 75 min of treadmill running at 70% of V˙O2max. Muscle glycogen content, respiratory gas variables, and blood and urine variables were measured in the morning for three consecutive days of training (days 1-3) and on the following morning after training (day 4). As an indication of endurance capacity, time to exhaustion at 19.0 ± 0.8 km·h to elicit 90% of V˙O2max was evaluated on day 4. RESULTS During the training period, body weight, fat-free mass, and skeletal muscle volume were significantly reduced in LEA (P = 0.02 for body weight and skeletal muscle volume, P = 0.01 for fat-free mass). Additionally, muscle glycogen content was significantly reduced in LEA (~30%, P < 0.001), with significantly lower values than those in NEA (P < 0.001). Time to exhaustion was not significantly different between the two trials (~20 min, P = 0.39). CONCLUSIONS Three consecutive days of endurance training under LEA decreased muscle glycogen content with lowered body weight. However, endurance capacity was not significantly impaired.
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Non-carbohydrate Dietary Factors and Their Influence on Post-Exercise Glycogen Storage: a Review.
Lawler, TP, Cialdella-Kam, L
Current nutrition reports. 2020;(4):394-404
Abstract
The optimization of post-exercise glycogen synthesis can improve endurance performance, delay fatigue in subsequent bouts, and accelerate recovery from exercise. High carbohydrate intakes (1.2 g/kg of body weight/h) are recommended in the first 4 h after exercise. However, athletes may struggle to consume carbohydrates at those levels. PURPOSE OF REVIEW Thus, we aimed to determine whether the consumption of non-carbohydrate dietary factors (creatine, glutamine, caffeine, flavonoids, and alcohol) enhances post-exercise glycogen synthesis. RECENT FINDINGS Trained athletes may not realize the benefits of creatine loading on glycogen synthesis. The impacts of caffeine, glutamine, flavonoids, and alcohol on post-exercise glycogen synthesis are poorly understood. Other ergogenic benefits to exercise performance, however, have been reported for creatine, glutamine, caffeine, and flavonoids, which were beyond the scope of this review. Evidence in trained athletes is limited and inconclusive on the impact of these non-carbohydrate dietary factors on post-exercise glycogen synthesis.
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Vacuoles, Often Containing Glycogen, Are a Consistent Finding in Hypokalemic Periodic Paralysis.
Holm-Yildiz, S, Krag, T, Witting, N, Duno, M, Soerensen, T, Vissing, J
Journal of neuropathology and experimental neurology. 2020;(10):1127-1129