Ingestion of glucose or sucrose prevents liver but not muscle glycogen depletion during prolonged endurance-type exercise in trained cyclists.
The purpose of this study was to define the effect of glucose ingestion compared with sucrose ingestion on liver and muscle glycogen depletion during prolonged endurance-type exercise. Fourteen cyclists completed two 3-h bouts of cycling at 50% of peak power output while ingesting either glucose or sucrose at a rate of 1.7 g/min (102 g/h). Four cyclists performed an additional third test for reference in which only water was consumed. We employed (13)C magnetic resonance spectroscopy to determine liver and muscle glycogen concentrations before and after exercise. Expired breath was sampled during exercise to estimate whole body substrate use. After glucose and sucrose ingestion, liver glycogen levels did not show a significant decline after exercise (from 325 ± 168 to 345 ± 205 and 321 ± 177 to 348 ± 170 mmol/l, respectively; P > 0.05), with no differences between treatments. Muscle glycogen concentrations declined (from 101 ± 49 to 60 ± 34 and 114 ± 48 to 67 ± 34 mmol/l, respectively; P < 0.05), with no differences between treatments. Whole body carbohydrate utilization was greater with sucrose (2.03 ± 0.43 g/min) vs. glucose (1.66 ± 0.36 g/min; P < 0.05) ingestion. Both liver (from 454 ± 33 to 283 ± 82 mmol/l; P < 0.05) and muscle (from 111 ± 46 to 67 ± 31 mmol/l; P < 0.01) glycogen concentrations declined during exercise when only water was ingested. Both glucose and sucrose ingestion prevent liver glycogen depletion during prolonged endurance-type exercise. Sucrose ingestion does not preserve liver glycogen concentrations more than glucose ingestion. However, sucrose ingestion does increase whole body carbohydrate utilization compared with glucose ingestion. This trial was registered at https://www.clinicaltrials.gov as NCT02110836.
Department for Health, University of Bath, Bath, United Kingdom; Faculty of Health and Life Sciences, Northumbria University, Newcastle-upon-Tyne, United Kingdom;
Javier T
JT
Gonzalez
Faculty of Health and Life Sciences, Northumbria University, Newcastle-upon-Tyne, United Kingdom; Department of Human Movement Sciences, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+ (MUMC+), Maastricht, The Netherlands; and.
Cas J
CJ
Fuchs
Newcastle Magnetic Resonance Centre, Institute of Cellular Medicine, Newcastle University, Newcastle-upon-Tyne, United Kingdom.
Fiona E
FE
Smith
Newcastle Magnetic Resonance Centre, Institute of Cellular Medicine, Newcastle University, Newcastle-upon-Tyne, United Kingdom.
Pete E
PE
Thelwall
Newcastle Magnetic Resonance Centre, Institute of Cellular Medicine, Newcastle University, Newcastle-upon-Tyne, United Kingdom.
Roy
R
Taylor
Faculty of Health and Life Sciences, Northumbria University, Newcastle-upon-Tyne, United Kingdom;
Emma J
EJ
Stevenson
Newcastle Magnetic Resonance Centre, Institute of Cellular Medicine, Newcastle University, Newcastle-upon-Tyne, United Kingdom.
Michael I
MI
Trenell
Department of Human Movement Sciences, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+ (MUMC+), Maastricht, The Netherlands; and.
Naomi M
NM
Cermak
Department of Human Movement Sciences, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+ (MUMC+), Maastricht, The Netherlands; and l.vanloon@maastrichtuniversity.nl.
Luc J C
LJ
van Loon
D000284:Administration, Oral; D000328:Adult; D001642:Bicycling / Q000502:physiology*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D015444:Exercise / Q000502:physiology; D005947:Glucose / Q000008:administration & dosage*; D006003:Glycogen / Q000378:metabolism*; D006801:Humans; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D010807:Physical Endurance / Q000187:drug effects / Q000502:physiology*; D013395:Sucrose / Q000008:administration & dosage*; D055815:Young Adult
D013395:Sucrose; D006003:Glycogen; D005947:Glucose
glucose; hepatic glycogen; metabolism; nutrition; sucrose