PMID- 12527974
OWN - NLM
STAT- MEDLINE
DCOM- 20030721
LR  - 20061115
IS  - 1439-6319 (Print)
IS  - 1439-6319 (Linking)
VI  - 88
IP  - 4-5
DP  - 2003 Jan
TI  - Metabolic profile of 4 h cycling in the field with varying amounts of 
      carbohydrate supply.
PG  - 431-7
AB  - Several laboratory studies have demonstrated a performance-enhancing effect of 
      carbohydrate (CHO) supplementations during endurance sessions of long duration. 
      However, the transferability of these results to real training and competition 
      circumstances has not been conclusively shown. Therefore, we tried to test the 
      influence of graded CHO substitution on substrate utilization and selected 
      physiological parameters under standardized but practically orientated field 
      conditions. Fourteen endurance-trained male subjects [mean (SD): 25 (5) years, 72 
      (9) kg, .VO(2max) 67 (6) ml.min(-1).kg(-1), individual anaerobic threshold (IAT) 
      269 (30) W] after a stepwise increasing pre-test had to perform three 4-h 
      endurance rides on their own bicycles with simultaneous spiroergometry: constant 
      workload 70% IAT (monitoring by SRM-System). Before and during exercise, 
      solutions without (0%), with 6% or 12% CHO were administered double-blindly and 
      in randomized order (total volume: 50 ml.kg(-1)). After cessation of exercise, 
      significant differences between 0% and both CHO concentrations were detected for 
      blood glucose (GLU; 75 mg dl(-1) for 0% vs 101 mg dl(-1) for 6% vs 115 mg dl(-1) 
      for 12%; P<0.001) and respiratory exchange ratio (0.84 vs 0.88 vs 0.90; P<0.01; 
      correlation to GLU: r=0.46, P<0.05). Free fatty acids (0.19 vs 0.16 vs 0.10 mmol 
      l(-1)) and glycerol (0.41 vs 0.22 vs 0.12 mmol l(-1)) were significantly 
      different between the endurance trials in a dose-dependent manner (both P<0.001). 
      Lactate concentration ( P=0.42) and heart rate ( P=0.12) had no significant 
      influence from CHO substitution. We conclude that CHO substitution during 4-h 
      endurance training inhibits lipolysis in a dose-dependent manner and enhances 
      aerobic glycolysis. This proves that earlier laboratory findings can be 
      replicated under field conditions using modern portable equipment.
FAU - Meyer, T
AU  - Meyer T
AD  - Institute of Sports and Preventive Medicine, University of Saarland, Faculty of 
      Clinical Medicine, 66041 Saarbrucken, Germany. t.meyer@rz.uni-sb.de
FAU - Gabriel, H H W
AU  - Gabriel HH
FAU - Auracher, M
AU  - Auracher M
FAU - Scharhag, J
AU  - Scharhag J
FAU - Kindermann, W
AU  - Kindermann W
LA  - eng
PT  - Clinical Trial
PT  - Journal Article
PT  - Randomized Controlled Trial
PT  - Research Support, Non-U.S. Gov't
DEP - 20021119
PL  - Germany
TA  - Eur J Appl Physiol
JT  - European journal of applied physiology
JID - 100954790
RN  - 0 (Blood Glucose)
RN  - 0 (Carbohydrates)
SB  - IM
MH  - Adult
MH  - Anaerobic Threshold
MH  - Bicycling/*physiology
MH  - Blood Glucose/analysis
MH  - Carbohydrates/*administration & dosage
MH  - Dose-Response Relationship, Drug
MH  - Double-Blind Method
MH  - Glycolysis/drug effects
MH  - Humans
MH  - Lipolysis/drug effects
MH  - Male
MH  - Oxygen Consumption
MH  - Physical Education and Training
MH  - Physical Endurance
MH  - Pulmonary Gas Exchange/drug effects
MH  - Time Factors
EDAT- 2003/01/16 04:00
MHDA- 2003/07/23 05:00
CRDT- 2003/01/16 04:00
PHST- 2002/07/09 00:00 [accepted]
PHST- 2003/01/16 04:00 [pubmed]
PHST- 2003/07/23 05:00 [medline]
PHST- 2003/01/16 04:00 [entrez]
AID - 10.1007/s00421-002-0712-3 [doi]
PST - ppublish
SO  - Eur J Appl Physiol. 2003 Jan;88(4-5):431-7. doi: 10.1007/s00421-002-0712-3. Epub 
      2002 Nov 19.