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Kojima C, Ishibashi A, Ebi K, Goto K. Exogenous glucose oxidation during endurance exercise under low energy availability. PLoS One 2022; 17:e0276002. [PMID: 36223366 PMCID: PMC9555626 DOI: 10.1371/journal.pone.0276002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 09/27/2022] [Indexed: 11/07/2022] Open
Abstract
The present study was conducted to determine the effect of endurance exercise under low energy availability (EA) on exogenous glucose oxidation during endurance exercise. Ten active males (21.4 ± 0.6 years, 170.4 ± 1.4 cm, 62.4 ± 1.5 kg, 21.5 ± 0.4 kg/m2) completed two trials, consisting of two consecutive days (days 1 and 2) of endurance training under low EA (19.9 ± 0.2 kcal/kg fat free mass [FFM]/day, LEA trial) or normal EA (46.4 ± 0.1 kcal/kg FFM/day, NEA trial). The order of these two trials was randomized with at least a 1-week interval between trials. As an endurance training, participants performed 60 min of treadmill running at 70% of maximal oxygen uptake ( V˙O2max) during two consecutive days (on days 1 and 2). On day 1, the endurance training was performed with consumed individually manipulated meals. During the endurance exercise on day 2, exogenous glucose oxidation was evaluated using 13C-labeled glucose, and respiratory gas samples were collected. In addition, blood glucose and lactate concentrations were measured immediately after exercise on day 2. Body composition, blood parameters, and resting respiratory gas variables were evaluated under overnight fasting on days 1 and 2. Body weight was significantly reduced in the LEA trial on day2 (day1: 61.8 ± 1.4 kg, day 2: 61.3 ± 1.4 kg, P < 0.001). There were no significant differences between trials in 13C excretion (P = 0.33) and area under the curve during the 60 min of exercise (LEA trial: 40.4 ± 3.1 mmol•60min, NEA trial: 40.4 ± 3.1 mmol•60min, P = 0.99). However, the respiratory exchange ratio (RER, LEA trial: 0.88 ± 0.01, NEA trial: 0.90 ± 0.01) and carbohydrate oxidation (LEA trial: 120.1 ± 8.8 g, NEA trial: 136.8 ± 8.6 g) during endurance exercise showed significantly lower values in the LEA trial than in the NEA trial (P = 0.01 for RER and carbohydrate oxidation). Serum insulin and total ketone body concentrations were significantly changed after a day of endurance training under low EA (P = 0.04 for insulin, P < 0.01 for total ketone). In conclusion, low EA during endurance exercise reduced systemic carbohydrate oxidation; however, exogenous glucose oxidation (evaluated by 13C excretion) remained unchanged during exercise under low EA.
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Affiliation(s)
- Chihiro Kojima
- Japan Institute of Sports Sciences, Nishigaoka, Kitaku, Tokyo, Japan
| | - Aya Ishibashi
- Department of Life Science, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Kumiko Ebi
- Graduate School of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Kazushige Goto
- Graduate School of Sport and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
- * E-mail:
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Rowe JT, King RFGJ, King AJ, Morrison DJ, Preston T, Wilson OJ, O'Hara JP. Glucose and Fructose Hydrogel Enhances Running Performance, Exogenous Carbohydrate Oxidation, and Gastrointestinal Tolerance. Med Sci Sports Exerc 2022; 54:129-140. [PMID: 34334720 DOI: 10.1249/mss.0000000000002764] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE Beneficial effects of carbohydrate (CHO) ingestion on exogenous CHO oxidation and endurance performance require a well-functioning gastrointestinal (GI) tract. However, GI complaints are common during endurance running. This study investigated the effect of a CHO solution-containing sodium alginate and pectin (hydrogel) on endurance running performance, exogenous and endogenous CHO oxidation, and GI symptoms. METHODS Eleven trained male runners, using a randomized, double-blind design, completed three 120-min steady-state runs at 68% V˙O2max, followed by a 5-km time-trial. Participants ingested 90 g·h-1 of 2:1 glucose-fructose (13C enriched) as a CHO hydrogel, a standard CHO solution (nonhydrogel), or a CHO-free placebo during the 120 min. Fat oxidation, total and exogenous CHO oxidation, plasma glucose oxidation, and endogenous glucose oxidation from liver and muscle glycogen were calculated using indirect calorimetry and isotope ratio mass spectrometry. GI symptoms were recorded throughout the trial. RESULTS Time-trial performance was 7.6% and 5.6% faster after hydrogel ([min:s] 19:29 ± 2:24, P < 0.001) and nonhydrogel (19:54 ± 2:23, P = 0.002), respectively, versus placebo (21:05 ± 2:34). Time-trial performance after hydrogel was 2.1% faster (P = 0.033) than nonhydrogel. Absolute and relative exogenous CHO oxidation was greater with hydrogel (68.6 ± 10.8 g, 31.9% ± 2.7%; P = 0.01) versus nonhydrogel (63.4 ± 8.1 g, 29.3% ± 2.0%; P = 0.003). Absolute and relative endogenous CHO oxidation was lower in both CHO conditions compared with placebo (P < 0.001), with no difference between CHO conditions. Absolute and relative liver glucose oxidation and muscle glycogen oxidation were not different between CHO conditions. Total GI symptoms were not different between hydrogel and placebo, but GI symptoms were higher in nonhydrogel compared with placebo and hydrogel (P < 0.001). CONCLUSION The ingestion of glucose and fructose in hydrogel form during running benefited endurance performance, exogenous CHO oxidation, and GI symptoms compared with a standard CHO solution.
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Affiliation(s)
| | | | - Andy J King
- Mary Mackillop Institute for Health Research, Australian Catholic University, Melbourne, AUSTRALIA
| | - Douglas J Morrison
- Scottish Universities Environmental Research Centre, University of Glasgow, Glasgow, UNITED KINGDOM
| | - Thomas Preston
- Scottish Universities Environmental Research Centre, University of Glasgow, Glasgow, UNITED KINGDOM
| | - Oliver J Wilson
- Carnegie School of Sport, Leeds Beckett University, Leeds, UNITED KINGDOM
| | - John P O'Hara
- Carnegie School of Sport, Leeds Beckett University, Leeds, UNITED KINGDOM
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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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4
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Griffiths A, Deighton K, Boos CJ, Rowe J, Morrison DJ, Preston T, King R, O'Hara JP. Carbohydrate Supplementation and the Influence of Breakfast on Fuel Use in Hypoxia. Med Sci Sports Exerc 2021; 53:785-795. [PMID: 33044437 DOI: 10.1249/mss.0000000000002536] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
PURPOSE This study investigated the effect of carbohydrate supplementation on substrate oxidation during exercise in hypoxia after preexercise breakfast consumption and omission. METHODS Eleven men walked in normobaric hypoxia (FiO2 ~11.7%) for 90 min at 50% of hypoxic V˙O2max. Participants were supplemented with a carbohydrate beverage (1.2 g·min-1 glucose) and a placebo beverage (both enriched with U-13C6 D-glucose) after breakfast consumption and after omission. Indirect calorimetry and isotope ratio mass spectrometry were used to calculate carbohydrate (exogenous and endogenous [muscle and liver]) and fat oxidation. RESULTS In the first 60 min of exercise, there was no significant change in relative substrate oxidation in the carbohydrate compared with placebo trial after breakfast consumption or omission (both P = 0.99). In the last 30 min of exercise, increased relative carbohydrate oxidation occurred in the carbohydrate compared with placebo trial after breakfast omission (44.0 ± 8.8 vs 28.0 ± 12.3, P < 0.01) but not consumption (51.7 ± 12.3 vs 44.2 ± 10.4, P = 0.38). In the same period, a reduction in relative liver (but not muscle) glucose oxidation was observed in the carbohydrate compared with placebo trials after breakfast consumption (liver, 7.7% ± 1.6% vs 14.8% ± 2.3%, P < 0.01; muscle, 25.4% ± 9.4% vs 29.4% ± 11.1%, P = 0.99) and omission (liver, 3.8% ± 0.8% vs 8.7% ± 2.8%, P < 0.01; muscle, 19.4% ± 7.5% vs 19.2% ± 12.2%, P = 0.99). No significant difference in relative exogenous carbohydrate oxidation was observed between breakfast consumption and omission trials (P = 0.14). CONCLUSION In acute normobaric hypoxia, carbohydrate supplementation increased relative carbohydrate oxidation during exercise (>60 min) after breakfast omission, but not consumption.
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Affiliation(s)
- Alex Griffiths
- Carnegie School of Sport, Leeds Beckett University, Leeds, UNITED KINGDOM
| | - Kevin Deighton
- Carnegie School of Sport, Leeds Beckett University, Leeds, UNITED KINGDOM
| | | | - Joshua Rowe
- Carnegie School of Sport, Leeds Beckett University, Leeds, UNITED KINGDOM
| | - Douglas J Morrison
- Stable Isotope Biochemistry Laboratory, SUERC, University of Glasgow. East Kilbride, Scotland, UNITED KINGDOM
| | - Tom Preston
- Stable Isotope Biochemistry Laboratory, SUERC, University of Glasgow. East Kilbride, Scotland, UNITED KINGDOM
| | - Roderick King
- Carnegie School of Sport, Leeds Beckett University, Leeds, UNITED KINGDOM
| | - John P O'Hara
- Carnegie School of Sport, Leeds Beckett University, Leeds, UNITED KINGDOM
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Margolis LM, O’Hara JP, Griffiths A, Wolfe RW, Young AJ, Pasiakos SM. Isotope tracer assessment of exogenous glucose oxidation during aerobic exercise in hypoxia. Physiol Rep 2020; 8:e14594. [PMID: 32959522 PMCID: PMC7507501 DOI: 10.14814/phy2.14594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 08/19/2020] [Indexed: 11/24/2022] Open
Affiliation(s)
- Lee M. Margolis
- U.S. Army Research Institute of Environmental MedicineNatickMAUSA
| | | | | | - Robert W. Wolfe
- Department of GeriatricsCenter for Translational Research in Aging and LongevityDonald W. Reynolds Institute on AgingUniversity of Arkansas for Medical SciencesLittle RockARUSA
| | - Andrew J. Young
- U.S. Army Research Institute of Environmental MedicineNatickMAUSA
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O'Hara JP, Duckworth L, Black A, Woods DR, Mellor A, Boos C, Gallagher L, Tsakirides C, Arjomandkhah NC, Morrison DJ, Preston T, King RFGJ. Fuel Use during Exercise at Altitude in Women with Glucose-Fructose Ingestion. Med Sci Sports Exerc 2020; 51:2586-2594. [PMID: 31206498 DOI: 10.1249/mss.0000000000002072] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
PURPOSE This study compared the coingestion of glucose and fructose on exogenous and endogenous substrate oxidation during prolonged exercise at terrestrial high altitude (HA) versus sea level, in women. METHOD Five women completed two bouts of cycling at the same relative workload (55% Wmax) for 120 min on acute exposure to HA (3375 m) and at sea level (~113 m). In each trial, participants ingested 1.2 g·min of glucose (enriched with C glucose) and 0.6 g·min of fructose (enriched with C fructose) before and every 15 min during exercise. Indirect calorimetry and isotope ratio mass spectrometry were used to calculate fat oxidation, total and exogenous carbohydrate oxidation, plasma glucose oxidation, and endogenous glucose oxidation derived from liver and muscle glycogen. RESULTS The rates and absolute contribution of exogenous carbohydrate oxidation was significantly lower at HA compared with sea level (effect size [ES] > 0.99, P < 0.024), with the relative exogenous carbohydrate contribution approaching significance (32.6% ± 6.1% vs 36.0% ± 6.1%, ES = 0.56, P = 0.059) during the second hour of exercise. In comparison, no significant differences were observed between HA and sea level for the relative and absolute contributions of liver glucose (3.2% ± 1.2% vs 3.1% ± 0.8%, ES = 0.09, P = 0.635 and 5.1 ± 1.8 vs 5.4 ± 1.7 g, ES = 0.19, P = 0.217), and muscle glycogen (14.4% ± 12.2% vs 15.8% ± 9.3%, ES = 0.11, P = 0.934 and 23.1 ± 19.0 vs 28.7 ± 17.8 g, ES = 0.30, P = 0.367). Furthermore, there was no significant difference in total fat oxidation between HA and sea level (66.3 ± 21.4 vs 59.6 ± 7.7 g, ES = 0.32, P = 0.557). CONCLUSIONS In women, acute exposure to HA reduces the reliance on exogenous carbohydrate oxidation during cycling at the same relative exercise intensity.
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Affiliation(s)
- John P O'Hara
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UNITED KINGDOM
| | - Lauren Duckworth
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UNITED KINGDOM
| | - Alistair Black
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UNITED KINGDOM
| | - David R Woods
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UNITED KINGDOM.,Royal Centre for Defence Medicine, Birmingham, UNITED KINGDOM.,Northumbria NHS Trust and Newcastle Trust, UNITED KINGDOM
| | - Adrian Mellor
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UNITED KINGDOM.,Royal Centre for Defence Medicine, Birmingham, UNITED KINGDOM.,James Cook University Hospital, Middlesborough, UNITED KINGDOM
| | - Christopher Boos
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UNITED KINGDOM.,Department of Cardiology, Poole Hospital, Poole, Dorset, UNITED KINGDOM
| | - Liam Gallagher
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UNITED KINGDOM
| | - Costas Tsakirides
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UNITED KINGDOM
| | - Nicola C Arjomandkhah
- School of Social and Health Sciences, Leeds Trinity University, Leeds, UNITED KINGDOM
| | - Douglas J Morrison
- Scottish Universities Environmental Research Centre, University of Glasgow, East Kilbridge, UNITED KINGDOM
| | - Thomas Preston
- Scottish Universities Environmental Research Centre, University of Glasgow, East Kilbridge, UNITED KINGDOM
| | - Roderick F G J King
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UNITED KINGDOM
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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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King AJ, O'Hara JP, Arjomandkhah NC, Rowe J, Morrison DJ, Preston T, King RFGJ. Liver and muscle glycogen oxidation and performance with dose variation of glucose-fructose ingestion during prolonged (3 h) exercise. Eur J Appl Physiol 2019; 119:1157-1169. [PMID: 30840136 PMCID: PMC6469629 DOI: 10.1007/s00421-019-04106-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 02/15/2019] [Indexed: 11/28/2022]
Abstract
PURPOSE This study investigated the effect of small manipulations in carbohydrate (CHO) dose on exogenous and endogenous (liver and muscle) fuel selection during exercise. METHOD Eleven trained males cycled in a double-blind randomised order on 4 occasions at 60% [Formula: see text] for 3 h, followed by a 30-min time-trial whilst ingesting either 80 g h-1 or 90 g h-1 or 100 g h-1 13C-glucose-13C-fructose [2:1] or placebo. CHO doses met, were marginally lower, or above previously reported intestinal saturation for glucose-fructose (90 g h-1). Indirect calorimetry and stable mass isotope [13C] techniques were utilised to determine fuel use. RESULT Time-trial performance was 86.5 to 93%, 'likely, probable' improved with 90 g h-1 compared 80 and 100 g h-1. Exogenous CHO oxidation in the final hour was 9.8-10.0% higher with 100 g h-1 compared with 80 and 90 g h-1 (ES = 0.64-0.70, 95% CI 9.6, 1.4 to 17.7 and 8.2, 2.1 to 18.6). However, increasing CHO dose (100 g h-1) increased muscle glycogen use (101.6 ± 16.6 g, ES = 0.60, 16.1, 0.9 to 31.4) and its relative contribution to energy expenditure (5.6 ± 8.4%, ES = 0.72, 5.6, 1.5 to 9.8 g) compared with 90 g h-1. Absolute and relative muscle glycogen oxidation between 80 and 90 g h-1 were similar (ES = 0.23 and 0.38) though a small absolute (85.4 ± 29.3 g, 6.2, - 23.5 to 11.1) and relative (34.9 ± 9.1 g, - 3.5, - 9.6 to 2.6) reduction was seen in 90 g h-1 compared with 100 g h-1. Liver glycogen oxidation was not significantly different between conditions (ES < 0.42). Total fat oxidation during the 3-h ride was similar in CHO conditions (ES < 0.28) but suppressed compared with placebo (ES = 1.05-1.51). CONCLUSION 'Overdosing' intestinal transport for glucose-fructose appears to increase muscle glycogen reliance and negatively impact subsequent TT performance.
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Affiliation(s)
- Andy J King
- Carnegie School of Sport, Fairfax Hall, Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QT, UK.
| | - John P O'Hara
- Carnegie School of Sport, Fairfax Hall, Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QT, UK
| | | | - Josh Rowe
- Carnegie School of Sport, Fairfax Hall, Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QT, UK
| | | | - Thomas Preston
- Scottish Universities Environmental Research Centre, Glasgow, UK
| | - Roderick F G J King
- Carnegie School of Sport, Fairfax Hall, Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, LS6 3QT, UK
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King AJ, O'Hara JP, Morrison DJ, Preston T, King RFGJ. Carbohydrate dose influences liver and muscle glycogen oxidation and performance during prolonged exercise. Physiol Rep 2018; 6. [PMID: 29333721 PMCID: PMC5789655 DOI: 10.14814/phy2.13555] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 12/04/2017] [Accepted: 12/05/2017] [Indexed: 11/24/2022] Open
Abstract
This study investigated the effect of carbohydrate (CHO) dose and composition on fuel selection during exercise, specifically exogenous and endogenous (liver and muscle) CHO oxidation. Ten trained males cycled in a double‐blind randomized order on 5 occasions at 77% V˙O2max for 2 h, followed by a 30‐min time‐trial (TT) while ingesting either 60 g·h−1 (LG) or 75 g·h−113C‐glucose (HG), 90 g·h−1 (LGF) or 112.5 g·h−113C‐glucose‐13C‐fructose ([2:1] HGF) or placebo. CHO doses met or exceed reported intestinal transporter saturation for glucose and fructose. Indirect calorimetry and stable mass isotope [13C] tracer techniques were utilized to determine fuel use. TT performance was 93% “likely/probable” to be improved with LGF compared with the other CHO doses. Exogenous CHO oxidation was higher for LGF and HGF compared with LG and HG (ES > 1.34, P < 0.01), with the relative contribution of LGF (24.5 ± 5.3%) moderately higher than HGF (20.6 ± 6.2%, ES = 0.68). Increasing CHO dose beyond intestinal saturation increased absolute (29.2 ± 28.6 g·h−1, ES = 1.28, P = 0.06) and relative muscle glycogen utilization (9.2 ± 6.9%, ES = 1.68, P = 0.014) for glucose‐fructose ingestion. Absolute muscle glycogen oxidation between LG and HG was not significantly different, but was moderately higher for HG (ES = 0.60). Liver glycogen oxidation was not significantly different between conditions, but absolute and relative contributions were moderately attenuated for LGF (19.3 ± 9.4 g·h−1, 6.8 ± 3.1%) compared with HGF (30.5 ± 17.7 g·h−1, 10.1 ± 4.0%, ES = 0.79 & 0.98). Total fat oxidation was suppressed in HGF compared with all other CHO conditions (ES > 0.90, P = 0.024–0.17). In conclusion, there was no linear dose response for CHO ingestion, with 90 g·h−1 of glucose‐fructose being optimal in terms of TT performance and fuel selection.
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Affiliation(s)
- Andy J King
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
| | - John P O'Hara
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
| | - Douglas J Morrison
- Scottish Universities Environmental Research Centre, East Kilbride, United Kingdom
| | - Tom Preston
- Scottish Universities Environmental Research Centre, East Kilbride, United Kingdom
| | - Roderick F G J King
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
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10
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O'Hara JP, Woods DR, Mellor A, Boos C, Gallagher L, Tsakirides C, Arjomandkhah NC, Holdsworth DA, Cooke CB, Morrison DJ, Preston T, King RF. A comparison of substrate oxidation during prolonged exercise in men at terrestrial altitude and normobaric normoxia following the coingestion of 13C glucose and 13C fructose. Physiol Rep 2017; 5:5/1/e13101. [PMID: 28082428 PMCID: PMC5256160 DOI: 10.14814/phy2.13101] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 11/30/2016] [Accepted: 11/29/2016] [Indexed: 01/14/2023] Open
Abstract
This study compared the effects of coingesting glucose and fructose on exogenous and endogenous substrate oxidation during prolonged exercise at altitude and sea level, in men. Seven male British military personnel completed two bouts of cycling at the same relative workload (55% Wmax) for 120 min on acute exposure to altitude (3375 m) and at sea level (~113 m). In each trial, participants ingested 1.2 g·min−1 of glucose (enriched with 13C glucose) and 0.6 g·min−1 of fructose (enriched with 13C fructose) directly before and every 15 min during exercise. Indirect calorimetry and isotope ratio mass spectrometry were used to calculate fat oxidation, total and exogenous carbohydrate oxidation, plasma glucose oxidation, and endogenous glucose oxidation derived from liver and muscle glycogen. Total carbohydrate oxidation during the exercise period was lower at altitude (157.7 ± 56.3 g) than sea level (286.5 ± 56.2 g, P = 0.006, ES = 2.28), whereas fat oxidation was higher at altitude (75.5 ± 26.8 g) than sea level (42.5 ± 21.3 g, P = 0.024, ES = 1.23). Peak exogenous carbohydrate oxidation was lower at altitude (1.13 ± 0.2 g·min−1) than sea level (1.42 ± 0.16 g·min−1, P = 0.034, ES = 1.33). There were no differences in rates, or absolute and relative contributions of plasma or liver glucose oxidation between conditions during the second hour of exercise. However, absolute and relative contributions of muscle glycogen during the second hour were lower at altitude (29.3 ± 28.9 g, 16.6 ± 15.2%) than sea level (78.7 ± 5.2 g (P = 0.008, ES = 1.71), 37.7 ± 13.0% (P = 0.016, ES = 1.45). Acute exposure to altitude reduces the reliance on muscle glycogen and increases fat oxidation during prolonged cycling in men compared with sea level.
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Affiliation(s)
- John P O'Hara
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
| | - David R Woods
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom.,Royal Centre for Defence Medicine, Birmingham, United Kingdom.,Northumbria NHS Trust and Newcastle Trust, Newcastle, United Kingdom
| | - Adrian Mellor
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom.,Royal Centre for Defence Medicine, Birmingham, United Kingdom.,James Cook University Hospital, Middlesborough, United Kingdom
| | - Christopher Boos
- Department of Cardiology, Poole Hospital, Poole, Dorset, United Kingdom
| | - Liam Gallagher
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
| | - Costas Tsakirides
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
| | - Nicola C Arjomandkhah
- School of Social and Health Sciences, Leeds Trinity University, Leeds, United Kingdom
| | | | - Carlton B Cooke
- School of Social and Health Sciences, Leeds Trinity University, Leeds, United Kingdom
| | - Douglas J Morrison
- Scottish Universities Environmental Research Centre, Glasgow, United Kingdom
| | - Thomas Preston
- Scottish Universities Environmental Research Centre, Glasgow, United Kingdom
| | - Roderick Fgj King
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
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11
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Haman F, Mantha OL, Cheung SS, DuCharme MB, Taber M, Blondin DP, McGarr GW, Hartley GL, Hynes Z, Basset FA. Oxidative fuel selection and shivering thermogenesis during a 12- and 24-h cold-survival simulation. J Appl Physiol (1985) 2015; 120:640-8. [PMID: 26718783 DOI: 10.1152/japplphysiol.00540.2015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 12/27/2015] [Indexed: 11/22/2022] Open
Abstract
Because the majority of cold exposure studies are constrained to short-term durations of several hours, the long-term metabolic demands of cold exposure, such as during survival situations, remain largely unknown. The present study provides the first estimates of thermogenic rate, oxidative fuel selection, and muscle recruitment during a 24-h cold-survival simulation. Using combined indirect calorimetry and electrophysiological and isotopic methods, changes in muscle glycogen, total carbohydrate, lipid, protein oxidation, muscle recruitment, and whole body thermogenic rate were determined in underfed and noncold-acclimatized men during a simulated accidental exposure to 7.5 °C for 12 to 24 h. In noncold-acclimatized healthy men, cold exposure induced a decrease of ∼0.8 °C in core temperature and a decrease of ∼6.1 °C in mean skin temperature (range, 5.4-6.9 °C). Results showed that total heat production increased by approximately 1.3- to 1.5-fold in the cold and remained constant throughout cold exposure. Interestingly, this constant rise in Ḣprod and shivering intensity was accompanied by a large modification in fuel selection that occurred between 6 and 12 h; total carbohydrate oxidation decreased by 2.4-fold, and lipid oxidation doubled progressively from baseline to 24 h. Clearly, such changes in fuel selection dramatically reduces the utilization of limited muscle glycogen reserves, thus extending the predicted time to muscle glycogen depletion to as much as 15 days rather than the previous estimates of approximately 30-40 h. Further research is needed to determine whether this would also be the case under different nutritional and/or colder conditions.
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Affiliation(s)
- François Haman
- Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada;
| | - Olivier L Mantha
- Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada
| | - Stephen S Cheung
- Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada
| | - Michel B DuCharme
- Defense Research and Development Canada, Québec City, Québec, Canada
| | - Michael Taber
- Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada; Falck Safety Services Canada, Dartmouth, Novia Scotia, Canada; School Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Denis P Blondin
- Centre hospitalier universitaire de Sherbrooke, Sherbrooke, Québec, Canada; and
| | - Gregory W McGarr
- Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada
| | - Geoffrey L Hartley
- Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada
| | - Zach Hynes
- School Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - Fabien A Basset
- School Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
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12
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Dietary practices in isolated First Nations communities of northern Canada: combined isotopic and lipid markers provide a good qualitative assessment of store-bought vs locally harvested foods consumption. Nutr Diabetes 2013; 3:e92. [PMID: 24145576 PMCID: PMC3817348 DOI: 10.1038/nutd.2013.34] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 07/26/2013] [Accepted: 09/08/2013] [Indexed: 01/20/2023] Open
Abstract
OBJECTIVE: In First Nations communities of northwestern Ontario, where rates of type 2 diabetes mellitus are some of the highest in the world, ascertaining wild food dietary practices is extremely challenging owing to seasonal availability, environmental factors, life circumstances and language/cultural barriers. The purpose of this study was to determine whether analysis of isotopic and fatty acid (FA) profiles could provide more comprehensive information to discriminate between three categories of wild food consumption (that is, plants and animals) in two isolated First Nations communities of northwestern Ontario. In addition, this analysis also highlights whether wild food consumption as practiced in these two communities can increase circulating levels of polyunsaturated FAs (PUFAs), which provide a number of important metabolic benefits that could impact the prevention/treatment of T2DM. RESULTS: 13C enrichment (in expired CO2, plasma and hair), 15N enrichment (in hair) and FA profiles in plasma phospholipids (phospholipid fatty acid (PL-FA)) were quantified in men and in women consuming various amounts of wild food. 13C/12C ratios were lower and 15N/14N ratios were higher in participants consuming wild food at least once a week. In addition, FA results indicated that the relative contributions of 20:4 Ω-6 and 22:6 Ω-3 to total PL-FAs were higher and 18:2 Ω-6 lower in wild food consumers. CONCLUSION: Together, these findings confirm that isotopic and lipid markers discriminate between the different wild food categories in these two First Nations communities. Knowing the close relationship between dietary intake and the potential role of PUFA in the prevention/treatment of obesity and obesity-related diseases, it is critical to accurately measure the composition of diet for individuals in their specific environments.
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13
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O'Hara JP, Carroll S, Cooke CB, Morrison DJ, Preston T, King RFGJ. Preexercise galactose and glucose ingestion on fuel use during exercise. Med Sci Sports Exerc 2013; 44:1958-67. [PMID: 22525771 DOI: 10.1249/mss.0b013e318258bf85] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE This study determined the effect of ingesting galactose and glucose 30 min before exercise on exogenous and endogenous fuel use during exercise. METHODS Nine trained male cyclists completed three bouts of cycling at 60% W(max) for 120 min after an overnight fast. Thirty minutes before exercise, the cyclists ingested a fluid formulation containing placebo, 75 g of galactose (Gal), or 75 g of glucose (Glu) to which (13)C tracers had been added, in a double-blind randomized manner. Indirect calorimetry and isotope ratio mass spectrometry were used to calculate fat oxidation, total carbohydrate (CHO) oxidation, exogenous CHO oxidation, plasma glucose oxidation, and endogenous liver and muscle CHO oxidation rates. RESULTS Peak exogenous CHO oxidation was significantly higher after Glu (0.68 ± 0.08 g.min(-1), P < 0.05) compared with Gal (0.44 ± 0.02 g.min(-1)); however, mean rates were not significantly different (0.40 ± 0.03 vs. 0.36 ± 0.02 g.min(-1), respectively). Glu produced significantly higher exogenous CHO oxidation rates during the initial hour of exercise (P < 0.01), whereas glucose rates derived from Gal were significantly higher during the last hour (P < 0.01). Plasma glucose and liver glucose oxidation at 60 min of exercise were significantly higher for Glu (1.07 ± 0.1 g.min(-1), P < 0.05, and 0.57 ± 0.08 g.min(-1), P < 0.01) compared with Gal (0.64 ± 0.05 and 0.29 ± 0.03 g.min(-1), respectively). There were no significant differences in total CHO, whole body endogenous CHO, muscle glycogen, or fat oxidation between conditions. CONCLUSION The preexercise consumption of Glu provides a higher exogenous source of CHO during the initial stages of exercise, but Gal provides the predominant exogenous source of fuel during the latter stages of exercise and reduces the reliance on liver glucose.
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Affiliation(s)
- John P O'Hara
- Research Institute for Sport, Physical Activity and Leisure, Leeds Metropolitan University, Leeds, United Kingdom.
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14
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BLONDIN DENISP, PÉRONNET FRANÇOIS, HAMAN FRANÇOIS. Coingesting Glucose and Fructose in the Cold Potentiates Exogenous CHO Oxidation. Med Sci Sports Exerc 2012; 44:1706-14. [DOI: 10.1249/mss.0b013e318254e952] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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15
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Blondin DP, Péronnet F, Haman F. Effects of ingesting [13C]glucose early or late into cold exposure on substrate utilization. J Appl Physiol (1985) 2010; 109:654-62. [PMID: 20651221 DOI: 10.1152/japplphysiol.00440.2010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
One of the factors limiting the oxidation of exogenous glucose during cold exposure may be the delay in establishing a shivering steady state (approximately 60 min), reducing glucose uptake into skeletal muscle. Therefore, using indirect calorimetry and isotopic methodologies in non-cold-acclimatized men, the main purpose of this study was to determine whether ingesting glucose at a moment coinciding with the maximal shivering intensity could increase the utilization rate of the ingested glucose. (13)C-enriched glucose was ingested (800 mg/min) from the onset (G0) or after 60 min (G60) of cold exposure when the thermogenic rate was stabilized to low-intensity shivering (approximately 2.5 times resting metabolic rate). For the same quantity of glucose ingested, the oxidation rate of exogenous glucose was 35% higher in G60 (159+/-17 vs. 118+/-17 mg/min in G0) between minutes 60 and 90. By the end of cold exposure, exogenous glucose oxidation was significantly greater in G0, reaching 231+/-14 mg/min, approximately 15% higher than the only rates previously reported. This considerably reduced the utilization of endogenous reserves over time and compared with the G60 condition. This study also demonstrates a fall in muscle glycogen utilization, when glucose was ingested from the onset of cold exposure (from approximately 150 to approximately 75 mg/min). Together, these findings indicate the importance of ingesting glucose immediately on exposure to a cold condition, relying on shivering thermogenesis and sustaining that consumption for as long as possible. This substrate not only provides an auxiliary fuel source for shivering thermogenesis, but, more importantly, preserves the limited endogenous glucose reserves.
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Affiliation(s)
- Denis P Blondin
- Institut de Recherche de l'Hôpital Montfort, Faculty of Health Sciences, University of Ottawa, 125 Univ. St., Ottawa, Ontario, Canada K1N 6N5
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16
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Smith JW, Zachwieja JJ, Péronnet F, Passe DH, Massicotte D, Lavoie C, Pascoe DD. Fuel selection and cycling endurance performance with ingestion of [13C]glucose: evidence for a carbohydrate dose response. J Appl Physiol (1985) 2010; 108:1520-9. [DOI: 10.1152/japplphysiol.91394.2008] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Endurance performance and fuel selection while ingesting glucose (15, 30, and 60 g/h) was studied in 12 cyclists during a 2-h constant-load ride [∼77% peak O2 uptake] followed by a 20-km time trial. Total fat and carbohydrate (CHO) oxidation and oxidation of exogenous glucose, plasma glucose, glucose released from the liver, and muscle glycogen were computed using indirect respiratory calorimetry and tracer techniques. Relative to placebo (210 ± 36 W), glucose ingestion increased the time trial mean power output (%improvement, 90% confidence limits: 7.4, 1.4 to 13.4 for 15 g/h; 8.3, 1.4 to 15.2 for 30 g/h; and 10.7, 1.8 to 19.6 for 60 g/h glucose ingested; effect size = 0.46). With 60 g/h glucose, mean power was 2.3, 0.4 to 4.2% higher, and 3.1, 0.5 to 5.7% higher than with 30 and 15 g/h, respectively, suggesting a relationship between the dose of glucose ingested and improvements in endurance performance. Exogenous glucose oxidation increased with ingestion rate (0.17 ± 0.04, 0.33 ± 0.04, and 0.52 ± 0.09 g/min for 15, 30, and 60 g/h glucose), but endogenous CHO oxidation was reduced only with 30 and 60 g/h due to the progressive inhibition of glucose released from the liver (probably related to higher plasma insulin concentration) with increasing ingestion rate without evidence for muscle glycogen sparing. Thus ingestion of glucose at low rates improved cycling time trial performance in a dose-dependent manner. This was associated with a small increase in CHO oxidation without any reduction in muscle glycogen utilization.
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Affiliation(s)
| | | | - François Péronnet
- Département de kinésiologie, Université de Montréal, Montreal, Quebec, Canada
| | | | - Denis Massicotte
- Département de Kinanthropologie, Université du Québec à Montréal, Montreal
| | - Carole Lavoie
- Département des Sciences de l'activité Physique, Université du Québec à Trois-Rivières, Trois-Rivières, Quebec, Canada; and
| | - David D. Pascoe
- Department of Kinesiology, Auburn University, Auburn, Alabama
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17
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Effects of two glucose ingestion rates on substrate utilization during moderate-intensity shivering. Eur J Appl Physiol 2009; 108:289-300. [PMID: 19779734 DOI: 10.1007/s00421-009-1210-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/14/2009] [Indexed: 10/20/2022]
Abstract
Although the importance of food consumption to survive in the cold is well established, most shivering studies have focused on fuel selection in fasting subjects. Therefore, the aim of the present study was to provide the first estimates of exogenous glucose as well as liver and muscle glycogen oxidation rates of non-cold acclimatized men (n = 6) ingesting glucose in trace amounts (Control; C), and at rates of 400 mg min(-1) (Low Glucose; LG), and 800 mg min(-1) (High Glucose; HG) during moderate-intensity shivering (~3 times resting metabolic rate or ~20% VO(2max)) using indirect calorimetry and stable isotope methodologies. Exogenous glucose oxidation peaked at ~200 mg min(-1) at the lowest glucose ingestion rate (~400 mg min(-1)). In addition, glucose ingestion increased the contribution of plasma glucose to total heat production by ~50% but did not change the role played by muscle glycogen (~27% of heat production for control condition and ~23-28% for LG and HG). Instead, the contribution of liver-derived glucose to total heat production was reduced by 40-60% in LG and HG, respectively. In conclusion, glucose ingestion even at low rates contributes a significant proportion of total heat production during moderate intensity shivering and reduces the utilization of liver-derived glucose but not muscle glycogen.
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18
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Péronnet F, Abdelaoui M, Lavoie C, Marrao C, Kerr S, Massicotte D, Giesbrecht G. Effect of a 20-day ski trek on fuel selection during prolonged exercise at low workload with ingestion of 13C-glucose. Eur J Appl Physiol 2009; 106:41-9. [DOI: 10.1007/s00421-009-0987-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/06/2009] [Indexed: 10/21/2022]
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19
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Robitaille M, Dubé MC, Weisnagel SJ, Prud'homme D, Massicotte D, Péronnet F, Lavoie C. Substrate source utilization during moderate intensity exercise with glucose ingestion in Type 1 diabetic patients. J Appl Physiol (1985) 2007; 103:119-24. [PMID: 17431081 DOI: 10.1152/japplphysiol.01462.2006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Substrate oxidation and the respective contributions of exogenous glucose, glucose released from the liver, and muscle glycogen oxidation were measured by indirect respiratory calorimetry combined with tracer technique in eight control subjects and eight diabetic patients (5 men and 3 women in both groups) of similar age, height, body mass, and maximal oxygen uptake, over a 60-min exercise period on cycle ergometer at 50.8% (SD 4.0) maximal oxygen uptake [131.0 W (SD 38.2)]. The subjects and patients ingested a breakfast (containing ∼80 g of carbohydrates) 3 h before and 30 g of glucose (labeled with 13C) 15 min before the beginning of exercise. The diabetic patients also received their usual insulin dose [Humalog = 9.1 U (SD 0.9); Humulin N = 13.9 U (SD 4.4)] immediately before the breakfast. Over the last 30 min of exercise, the oxidation of carbohydrate [1.32 g/min (SD 0.48) and 1.42 g/min (SD 0.63)] and fat [0.33 g/min (SD 0.10) and 0.30 g/min (SD 0.10)] and their contribution to the energy yield were not significantly different in the control subjects and diabetic patients. Exogenous glucose oxidation was also not significantly different in the control subjects and diabetic patients [6.3 g/30 min (SD 1.3) and 5.2 g/30 min (SD 1.6), respectively]. In contrast, the oxidation of plasma glucose and oxidation of glucose released from the liver were significantly lower in the diabetic patients than in control subjects [14.5 g/30 min (SD 4.3) and 9.3 g/30 min (SD 2.8) vs. 27.9 g/30 min (SD 13.3) and 21.6 g/30 min (SD 12.8), respectively], whereas that of muscle glycogen was significantly higher [28.1 g/30 min (SD 15.5) vs. 11.6 g/30 min (SD 8.1)]. These data indicate that, compared with control subjects, in diabetic patients fed glucose before exercise, substrate oxidation and exogenous glucose oxidation overall are similar but plasma glucose oxidation is lower; this is associated with a compensatory higher utilization of muscle glycogen.
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Affiliation(s)
- M Robitaille
- Département de chimie-biologie et des sciences de l'activité physique, Université du Québec à Trois-Rivières, Trois-Rivières, Québec, Canada G9A 5H7
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20
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Harvey CR, Frew R, Massicotte D, Péronnet F, Rehrer NJ. Muscle glycogen oxidation during prolonged exercise measured with oral [13C]glucose: comparison with changes in muscle glycogen content. J Appl Physiol (1985) 2007; 102:1773-9. [PMID: 17272412 DOI: 10.1152/japplphysiol.00690.2006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Plasma glucose and muscle glycogen oxidation during prolonged exercise [75-min at 48 and 76% maximal O2 uptake (V̇o2 max)] were measured in eight well-trained male subjects [V̇o2 max = 4.50 l/min (SD 0.63)] using a simplified tracer technique in which a small amount of glucose highly enriched in 13C was ingested: plasma glucose oxidation was computed from 13C/12C in plasma glucose (which was stable beginning at minute 30 and minute 15 during exercise at 48 and 76% V̇o2 max, respectively) and 13CO2 production, and muscle glycogen oxidation was estimated by subtracting plasma glucose oxidation from total carbohydrate oxidation. Consistent data from the literature suggest that this small dose of exogenous glucose does not modify muscle glycogen oxidation and has little effect, if any, on plasma glucose oxidation. The percent contributions of plasma glucose and muscle glycogen oxidation to the energy yield at 48% V̇o2 max [15.1% (SD 3.8) and 45.9% (SD 5.8)] and at 76% V̇o2 max [15.4% (SD 3.6) and 59.8% (SD 9.2)] were well in line with data previously reported for similar work loads and exercise durations using conventional tracer techniques. The significant reduction in glycogen concentration measured from pre- and postexercise vastus lateralis muscle biopsies paralleled muscle glycogen oxidation calculated using the tracer technique and was larger at 76% than at 48% V̇o2 max. However, the correlation coefficients between these two estimates of muscle glycogen utilization were not different from zero at each of the two work loads. The simplified tracer technique used in the present experiment appears to be a valid alternative approach to the traditional tracer techniques for computing plasma glucose and muscle glycogen oxidation during prolonged exercise.
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Affiliation(s)
- C R Harvey
- School of Physical Education, University of Otago, Dunedin, New Zealand.
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21
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Haman F, Péronnet F, Kenny GP, Massicotte D, Lavoie C, Weber JM. Partitioning oxidative fuels during cold exposure in humans: muscle glycogen becomes dominant as shivering intensifies. J Physiol 2005; 566:247-56. [PMID: 15831534 PMCID: PMC1464733 DOI: 10.1113/jphysiol.2005.086272] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 03/07/2005] [Accepted: 04/13/2005] [Indexed: 01/22/2023] Open
Abstract
The effects of changes in shivering intensity on the relative contributions of plasma glucose, muscle glycogen, lipids and proteins to total heat production are unclear in humans. The goals of this study were: (1) to determine whether plasma glucose starts playing a more prominent role as shivering intensifies, (2) to quantify overall changes in fuel use in relation to the severity of cold exposure, and (3) to establish whether the fuel selection pattern of shivering is different from the classic fuel selection pattern of exercise. Using a combination of indirect calorimetry and stable isotope methodology, fuel metabolism was monitored in non-acclimatized adult men exposed for 90 mins to 10 degrees C (low-intensity shivering (L)) or 5 degrees C (moderate-intensity shivering (M)). Results show that plasma glucose oxidation is strongly stimulated by moderate shivering (+122% from L to M), but the relative contribution of this pathway to total heat generation always remains minor (< 15% of total heat production). Instead, muscle glycogen is responsible for most of the increase in heat production between L and M. By itself, the increase in CHO oxidation is responsible for the 100 W increase in metabolic rate observed between L and M, because rates of lipid and protein oxidation remain constant. This high reliance on CHO is not compatible with the well known fuel selection pattern of exercise, when considering the relatively low metabolic rates elicited by shivering (approximately 30% for M). We conclude that shivering and exercise of similar energy requirements appear to be supported by different fuel mixtures. Investigating the physiological mechanisms underlying why a muscle producing only heat (shivering), or significant movement (exercise), shows a different pattern of fuel selection at the same power output strikes us as a fascinating area for future research.
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Affiliation(s)
- François Haman
- Faculty of Health Sciences, University of Ottawa, 125 University St, Ottawa, Ontario, Canada K1N 6N5.
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22
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Abstract
It is generally accepted that carbohydrate (CHO) feeding during exercise can improve endurance capacity (time to exhaustion) and exercise performance during prolonged exercise (>2 h). More recently, studies have also shown ergogenic effects of CHO feeding during shorter exercise of high intensity ( approximately 1 h at >75% of maximum oxygen consumption). During prolonged exercise the mechanism behind this performance improvement is likely to be related to maintenance of high rates of CHO oxidation and the prevention of hypoglycemia. Nevertheless, other mechanisms may play a role, depending on the type of exercise and the specific conditions. The mechanism for performance improvements during higher-intensity exercise is less clear, but there is some evidence that CHO can have central effects. In the past few years, studies have investigated ways to optimize CHO delivery and bioavailability. An analysis of all studies available shows that a single CHO ingested during exercise will be oxidized at rates up to about 1 g/min, even when large amounts of CHO are ingested. Combinations of CHO that use different intestinal transporters for absorption (e.g., glucose and fructose) have been shown to result in higher oxidation rates, and this seems to be a way to increase exogenous CHO oxidation rates by 20% to 50%. The search will continue for ways to further improve CHO delivery and to improve the oxidation efficiency resulting in less accumulation of CHO in the gastrointestinal tract and potentially decreasing gastrointestinal problems during prolonged exercise.
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Affiliation(s)
- Asker E Jeukendrup
- Human Performance Laboratory, School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom.
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23
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Racette R, Péronnet F, Massicotte D, Lavoie C. Metabolic response to prolonged cycling with (13)C-glucose ingestion following downhill running. Eur J Appl Physiol 2004; 93:598-605. [PMID: 15578208 DOI: 10.1007/s00421-004-1240-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/15/2004] [Indexed: 11/25/2022]
Abstract
The purpose of this study was to describe the effect of muscle damage and delayed-onset muscle soreness (DOMS) on the metabolic response during a subsequent period of prolonged concentric exercise (120 min, approximately 61% V(.)O(2max), on a cycle ergometer), with ingestion of 3 g of (13)C-glucose/kg body mass. We hypothesized that the oxidation of plasma and exogenous glucose would be reduced, while the oxidation of glucose arising from muscle glycogen would be increased. Six male subjects were studied during exercise in a control situation and 2 days following downhill running, at a time when plasma creatine kinase (CK) activity was increased, and DOMS was present. Carbohydrate and lipid oxidation were computed from indirect respiratory calorimetry corrected for protein oxidation, while the oxidation of plasma glucose and muscle glycogen were computed from V(.)(13)CO(2) and the ratio of (13)C/(12)C in the plasma glucose. All data were presented as the mean and the standard error of the mean. The oxidation of protein (approximately 6% energy yield, in the control and the experimental trial), lipid (approximately 15 and approximately 18%), and carbohydrate (approximately 79 and approximately 76%), as well as that of plasma glucose (approximately 41 and approximately 46%), glucose from the liver (approximately 12 and approximately 14%), and glucose from muscle glycogen (approximately 38 and approximately 31%) were not significantly different between the control and experimental (DOMS) trials. The response of the plasma glucose, insulin, lactate, and free fatty acid concentrations was not modified by the previous eccentric exercise. These results indicate that the metabolic response to prolonged concentric exercise is not modified by muscle damage and DOMS resulting from a bout of eccentric exercise performed 2 days before.
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Affiliation(s)
- Ronald Racette
- Département de Kinésiologie, Université de Montréal, , Montréal, Québec, H3C 3J7, Canada
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24
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Haman F, Peronnet F, Kenny GP, Doucet E, Massicotte D, Lavoie C, Weber JM. Effects of carbohydrate availability on sustained shivering I. Oxidation of plasma glucose, muscle glycogen, and proteins. J Appl Physiol (1985) 2004; 96:32-40. [PMID: 12949018 DOI: 10.1152/japplphysiol.00427.2003] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Carbohydrates (CHO) can play an important thermogenic role during shivering, but the effect of their availability on the use of other oxidative fuels is unclear. Using indirect calorimetry and tracer methods ([U-13C]glucose ingestion), we have determined the specific contributions of plasma glucose, muscle glycogen, proteins, and lipids to total heat production (Hprod) in men exposed to cold for 2-h (liquid-conditioned suit perfused with 10 degrees C water). Measurements were made after low-CHO diet and exercise (Lo) and high-CHO diet without exercise (Hi). The size of CHO reserves had no effect on Hprod but a major impact on fuel selection before and during shivering. In the cold, a complete shift from lipid oxidation for Lo (53, 28, and 19% Hprod for lipids, CHO, and proteins, respectively) to CHO-based metabolism for Hi (23, 65, and 12% Hprod for lipids, CHO, and proteins, respectively) was observed. Plasma glucose oxidation remains a minor fuel under all conditions (<13% Hprod), falling to 7% Hprod for Lo. Therefore, adjusting plasma glucose oxidation to compensate for changes in muscle glycogen oxidation is not a strategy used for maintaining heat production. Instead, proteins and lipids share responsibility for this compensation. We conclude that humans can show remarkable flexibility in oxidative fuel selection to ensure that heat production is not compromised during sustained cold exposure.
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Affiliation(s)
- François Haman
- Biology Department, University of Ottawa, Ottawa, Ontario, Canada K1N 6N5
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25
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Haman F, Péronnet F, Kenny GP, Massicotte D, Lavoie C, Scott C, Weber JM. Effect of cold exposure on fuel utilization in humans: plasma glucose, muscle glycogen, and lipids. J Appl Physiol (1985) 2002; 93:77-84. [PMID: 12070189 DOI: 10.1152/japplphysiol.00773.2001] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The relative roles of circulatory glucose, muscle glycogen, and lipids in shivering thermogenesis are unclear. Using a combination of indirect calorimetry and stable isotope methodology ([U-13C]glucose ingestion), we have quantified the oxidation rates of these substrates in men acutely exposed to cold for 2 h (liquid conditioned suit perfused with 10 degrees C water). Cold exposure stimulated heat production by 2.6-fold and increased the oxidation of plasma glucose from 39.4 +/- 2.4 to 93.9 +/- 5.5 mg/min (+138%), of muscle glycogen from 126.6 +/- 7.8 to 264.2 +/- 36.9 mg glucosyl units/min (+109%), and of lipids from 46.9 +/- 3.2 to 176.5 +/- 17.3 mg/min (+376%). Despite the observed increase in plasma glucose oxidation, this fuel only supplied 10% of the energy for heat generation. The major source of carbohydrate was muscle glycogen (75% of all glucose oxidized), and lipids produced as much heat as all other fuels combined. During prolonged, low-intensity shivering, we conclude that total heat production is unequally shared among lipids (50%), muscle glycogen (30%), plasma glucose (10%), and proteins (10%). Therefore, future research should focus on lipids and muscle glycogen that provide most of the energy for heat production.
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Couture S, Massicotte D, Lavoie C, Hillaire-Marcel C, Péronnet F. Oral [(13)C]glucose and endogenous energy substrate oxidation during prolonged treadmill running. J Appl Physiol (1985) 2002; 92:1255-60. [PMID: 11842065 DOI: 10.1152/japplphysiol.00437.2001] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Six male subjects were studied during running exercise (120 min, 69% maximal oxygen consumption) with ingestion of a placebo or 3.5 g/kg of [(13)C]glucose (approximately 2 g/min). Indirect respiratory calorimetry corrected for urea excretion in urine and sweat, production of (13)CO(2) at the mouth, and changes in plasma glucose (13)C/(12)C were used to compute energy substrate oxidation. The oxidation rate of exogenous glucose increased from 1.02 at minute 60 to 1.22 g/min at minute 120 providing approximately 24 and 33% of the energy yield (%En). Glucose ingestion did not modify protein oxidation, which provided approximately 4-5%En, but significantly increased glucose oxidation by approximately 7%, reduced lipid oxidation by approximately 16%, and markedly reduced endogenous glucose oxidation (1.25 vs. 2.21 g/min between minutes 80 and 120, respectively). The oxidation rate of glucose released from the liver (0.38 and 0.47 g/min, or 10-13%En at minutes 60 and 120, respectively), and of plasma glucose (1.30-1.69 g/min, or 34 and 45%En and 50 and 75% of glucose oxidation) significantly increased from minutes 60 to 120, whereas the oxidation of muscle glycogen significantly decreased (1.28 to 0.58 g of glucose/min, or 34 and 16%En and 50 and 25% of glucose oxidation). These results indicate that, during moderate prolonged running exercise, ingestion of a very large amount of glucose significantly reduces endogenous glucose oxidation, thus sparing muscle and/or liver glycogen stores.
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Affiliation(s)
- Stéphane Couture
- Département de Kinésiologie, Université de Montréal, Montréal, Québec, Canada H3C 3J7
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Jeukendrup AE, Jentjens R. Oxidation of carbohydrate feedings during prolonged exercise: current thoughts, guidelines and directions for future research. Sports Med 2000; 29:407-24. [PMID: 10870867 DOI: 10.2165/00007256-200029060-00004] [Citation(s) in RCA: 157] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Although it is known that carbohydrate (CHO) feedings during exercise improve endurance performance, the effects of different feeding strategies are less clear. Studies using (stable) isotope methodology have shown that not all carbohydrates are oxidised at similar rates and hence they may not be equally effective. Glucose, sucrose, maltose, maltodextrins and amylopectin are oxidised at high rates. Fructose, galactose and amylose have been shown to be oxidised at 25 to 50% lower rates. Combinations of multiple transportable CHO may increase the total CHO absorption and total exogenous CHO oxidation. Increasing the CHO intake up to 1.0 to 1.5 g/min will increase the oxidation up to about 1.0 to 1.1 g/min. However, a further increase of the intake will not further increase the oxidation rates. Training status does not affect exogenous CHO oxidation. The effects of fasting and muscle glycogen depletion are less clear. The most remarkable conclusion is probably that exogenous CHO oxidation rates do not exceed 1.0 to 1.1 g/min. There is convincing evidence that this limitation is not at the muscular level but most likely located in the intestine or the liver. Intestinal perfusion studies seem to suggest that the capacity to absorb glucose is only slightly in excess of the observed entrance of glucose into the blood and the rate of absorption may thus be a factor contributing to the limitation. However, the liver may play an additional important role, in that it provides glucose to the bloodstream at a rate of about 1 g/min by balancing the glucose from the gut and from glycogenolysis/gluconeogenesis. It is possible that when large amounts of glucose are ingested absorption is a limiting factor, and the liver will retain some glucose and thus act as a second limiting factor to exogenous CHO oxidation.
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Affiliation(s)
- A E Jeukendrup
- Human Performance Laboratory, School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, England.
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Abstract
The purpose of this review is to evaluate the effectiveness of commercially available sports drinks by answering the questions: (i) will consuming a sports drink be beneficial to performance? and (ii) do different sports drinks vary in their effectiveness? To answer these questions we have considered the composition of commercially available sports drinks, examined the rationale for using them, and critically reviewed the vast number of studies that have investigated the effectiveness of sports drinks on performance. The focus is on the drinks that contain low carbohydrate concentrations (<10%) and are marketed for general consumption before and during exercise rather than those with carbohydrate concentrations >10%, which are intended for carbohydrate loading. Our conclusions are 3-fold. First, because of variations in drink composition and research design, much of the sports drinks research from the past cannot be applied directly to the effectiveness of currently available sports drinks. Secondly, in studies where a practical protocol has been used along with a currently available sports beverage, there is evidence to suggest that consuming a sports drinks will improve performance compared with consuming a placebo beverage. Finally, there is little evidence that any one sports drink is superior to any of the other beverages on the market.
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Affiliation(s)
- J S Coombes
- Centre for Human Movement, University of Tasmania, Launceston, Australia
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