PMID- 18046188
OWN - NLM
STAT- MEDLINE
DCOM- 20080225
LR  - 20071129
IS  - 0195-9131 (Print)
IS  - 0195-9131 (Linking)
VI  - 39
IP  - 12
DP  - 2007 Dec
TI  - Exogenous carbohydrate spares muscle glycogen in men and women during 10 h of 
      exercise.
PG  - 2171-9
AB  - PURPOSE: The purpose of the study was to evaluate the effects of carbohydrate 
      (CHO) supplementation on whole-body and net muscle substrate use during 10 h of 
      discontinuous exercise, simulating occupational settings in men and women. 
      METHODOLOGY: Recreationally trained subjects (N = 7 males, N = 6 females) 
      performed a graded exercise test on a treadmill (TM) and cycle ergometer (CE) to 
      determine ventilatory threshold (VT) and V O2peak. In a double-blind, randomized 
      crossover design, subjects received either CHO [20% maltodextrin (0.6 g.kg 
      FFM.h)] or flavored placebo (PLA) drink each hour across 10 h of exercise. 
      Exercise intensity was 71.3 +/- 3% and 72.4 +/- 4% VT for TM and CE, 
      respectively. Hourly exercise included 9 min of upper-body ergometery, 19 min of 
      cycling, and 20 min of treadmill walking, with a 1-min transition between modes, 
      followed by a 10-min rest and feeding period. The protocol was selected to 
      simulate arduous occupational settings. Vastus lateralis biopsies were obtained 
      before and after exercise. Expired gases were collected every other hour to 
      establish average rates of whole-body CHO and fat oxidation. Blood glucose (BG) 
      was measured continuously. RESULTS: Whole-body CHO oxidation was maintained 
      during CHO trial compared with the PLA trial. Net muscle glycogen use was 52% 
      higher for the PLA trial (176.0 +/- 16.7, 117.0 +/- 20.9 and 164.5 +/- 11.0, 
      133.8 +/- 10.9 mmol.kg w.w. for PLA and CHO, respectively, P < 0.05). There were 
      no significant sex-specific differences in glycogen use, whole-body substrate 
      oxidation, or BG values. CONCLUSION: The ingestion of CHO during long-duration 
      exercise decreases net muscle glycogen use while better maintaining whole-body 
      carbohydrate oxidation, and potentially increasing performance in field settings. 
      There are limited differences in sex-specific substrate oxidation.
FAU - Harger-Domitrovich, Stephanie G
AU  - Harger-Domitrovich SG
AD  - Department of Health and Human Performance, The University of Montana, Missoula, 
      MT 59812-1825, USA.
FAU - McClaughry, Anne E
AU  - McClaughry AE
FAU - Gaskill, Steven E
AU  - Gaskill SE
FAU - Ruby, Brent C
AU  - Ruby BC
LA  - eng
PT  - Journal Article
PL  - United States
TA  - Med Sci Sports Exerc
JT  - Medicine and science in sports and exercise
JID - 8005433
RN  - 0 (Carbohydrates)
RN  - 9005-79-2 (Glycogen)
SB  - IM
MH  - Adult
MH  - Carbohydrate Metabolism
MH  - Carbohydrates/*pharmacology
MH  - Cross-Over Studies
MH  - Energy Metabolism
MH  - Exercise/*physiology
MH  - Female
MH  - Glycogen/*metabolism
MH  - Humans
MH  - Lipid Metabolism
MH  - Male
MH  - Muscle, Skeletal/*physiology
MH  - Time Factors
EDAT- 2007/11/30 09:00
MHDA- 2008/02/26 09:00
CRDT- 2007/11/30 09:00
PHST- 2007/11/30 09:00 [pubmed]
PHST- 2008/02/26 09:00 [medline]
PHST- 2007/11/30 09:00 [entrez]
AID - 00005768-200712000-00010 [pii]
AID - 10.1249/mss.0b013e318157a650 [doi]
PST - ppublish
SO  - Med Sci Sports Exerc. 2007 Dec;39(12):2171-9. doi: 10.1249/mss.0b013e318157a650.