PMID- 8941515
OWN - NLM
STAT- MEDLINE
DCOM- 19970313
LR  - 20171213
IS  - 8750-7587 (Print)
IS  - 0161-7567 (Linking)
VI  - 81
IP  - 5
DP  - 1996 Nov
TI  - Reduced oxidation rates of ingested glucose during prolonged exercise with low 
      endogenous CHO availability.
PG  - 1952-7
AB  - This study investigated the effect of endogenous carbohydrate (CHO) availability 
      on oxidation rates of ingested glucose during moderate-intensity exercise. Seven 
      well-trained cyclists performed two trials of 120 min of cycling exercise in 
      random order at 57% maximal O2 consumption. Preexercise glycogen concentrations 
      were manipulated by glycogen-lowering exercise in combination with CHO 
      restriction [low-glycogen (LG) trial] or CHO loading [moderate-to-high-glycogen 
      (HG) trial]. In the LG and HG trials, subjects ingested 4 ml/kg body wt of an 8% 
      corn-derived glucose solution of high natural 13C abundance at the start, 
      followed by boluses of 2 ml/kg every 15 min. The third trial, in which 
      potato-derived glucose was ingested, served as a control test for background 
      correction. Exogenous glucose oxidation rates were calculated from the 13C 
      enrichment of the ingested glucose and of the breath CO2. Total CHO oxidation was 
      lower in the LG trial than in the HG trial during 60-120 min of exercise [84 +/- 
      7 (SE) vs. 116 +/- 8 g; P < 0.05]. Exogenous CHO oxidation in this period was 28% 
      lower in the LG trial compared with the HG trial. Maximal exogenous oxidation 
      rates were also lower (P < 0.05) in the LG trial (0.64 +/- 0.05 g/min) than in 
      the HG trial (0.88 +/- 0.04 g/min). This decreased utilization of exogenous 
      glucose was accompanied by increased plasma free fatty acid levels (2-3 times 
      higher) and lower insulin concentrations. It is concluded that glycogen-lowering 
      exercise, performed the evening before an exercise bout, in combination with CHO 
      restriction leads to a reduction of the oxidation rate of ingested glucose during 
      moderate-intensity exercise.
FAU - Jeukendrup, A E
AU  - Jeukendrup AE
AD  - Department of Human Biology, University Maastricht, The Netherlands. 
      A.Jeukendrup@HB.RuLimburg.NL
FAU - Borghouts, L B
AU  - Borghouts LB
FAU - Saris, W H
AU  - Saris WH
FAU - Wagenmakers, A J
AU  - Wagenmakers AJ
LA  - eng
PT  - Clinical Trial
PT  - Journal Article
PT  - Randomized Controlled Trial
PL  - United States
TA  - J Appl Physiol (1985)
JT  - Journal of applied physiology (Bethesda, Md. : 1985)
JID - 8502536
RN  - 0 (Blood Glucose)
RN  - 0 (Dietary Carbohydrates)
RN  - 0 (Fatty Acids, Nonesterified)
RN  - 0 (Insulin)
RN  - 142M471B3J (Carbon Dioxide)
RN  - IY9XDZ35W2 (Glucose)
SB  - IM
MH  - Adult
MH  - Anaerobic Threshold/physiology
MH  - Blood Glucose/metabolism
MH  - Carbon Dioxide/metabolism
MH  - Dietary Carbohydrates/metabolism/*pharmacology
MH  - Energy Metabolism/physiology
MH  - Exercise/*physiology
MH  - Fatty Acids, Nonesterified/blood
MH  - Glucose/*metabolism
MH  - Humans
MH  - Insulin/blood
MH  - Kinetics
MH  - Oxidation-Reduction
MH  - Physical Endurance/physiology
EDAT- 1996/11/01 00:00
MHDA- 1996/11/01 00:01
CRDT- 1996/11/01 00:00
PHST- 1996/11/01 00:00 [pubmed]
PHST- 1996/11/01 00:01 [medline]
PHST- 1996/11/01 00:00 [entrez]
AID - 10.1152/jappl.1996.81.5.1952 [doi]
PST - ppublish
SO  - J Appl Physiol (1985). 1996 Nov;81(5):1952-7. doi: 10.1152/jappl.1996.81.5.1952.