PMID- 22968309
OWN - NLM
STAT- MEDLINE
DCOM- 20130625
LR  - 20130118
IS  - 1530-0315 (Electronic)
IS  - 0195-9131 (Linking)
VI  - 45
IP  - 2
DP  - 2013 Feb
TI  - Curvilinear dose-response relationship of carbohydrate (0-120 g.h(-1)) and 
      performance.
PG  - 336-41
LID - 10.1249/MSS.0b013e31827205d1 [doi]
AB  - BACKGROUND: There is a lack of consensus regarding the optimal range of 
      carbohydrate (CHO) ingestion rates recommended for endurance athletes. PURPOSE: 
      This study investigated the relationship between CHO dose and cycling time trial 
      performance to identify an optimal range of CHO ingestion rates for endurance 
      performance. METHODS: Fifty-one cyclists and triathletes (28 +/- 7 yr, mean +/- SD) 
      across four research sites completed four trials. Each trial consisted of a 2-h 
      constant load ride at 95% of the workload that elicited a 4-mmol.L(-1) blood 
      lactate concentration immediately followed by a computer-simulated 20-km time 
      trial, which subjects were asked to complete as quickly as possible. Twelve CHO 
      electrolyte (18 mmol.L(-1) Na, 3 mmol.L(-1) K, and 11 mmol.L(-1) Cl) beverages 
      (three at each site) were tested in a double-blind manner, providing subjects 10, 
      20, 30, 40, 50, 60, 70, 80, 90, 100, 110, and 120 g CHO (1:1:1 
      glucose-fructose-maltodextrin) per hour during the 2-h constant load ride at a 
      fluid intake rate of 1 L.h(-1). All subjects also consumed a noncaloric placebo 
      on one counterbalanced test occasion. Data were natural log transformed, 
      subjected to a mixed-model analysis, and are reported as adjusted treatment 
      means. RESULTS: We estimate incremental performance improvements of 1.0%, 2.0%, 
      3.0%, 4.0%, and 4.7% at 9, 19, 31, 48, and 78 g.h, respectively, with diminishing 
      performance enhancement seen at CHO levels >78 g.h(-1). CONCLUSIONS: CHO beverage 
      ingestion and endurance ( approximately 160 min) performance appear to be related in a 
      curvilinear dose-response manner, with the best performance occurring with a CHO 
      (1:1:1 glucose-fructose-maltodextrin) ingestion rate of 78 g.h(-1).
FAU - Smith, Johneric W
AU  - Smith JW
AD  - Gatorade Sports Science Institute, Barrington, IL, USA.
FAU - Pascoe, David D
AU  - Pascoe DD
FAU - Passe, Dennis H
AU  - Passe DH
FAU - Ruby, Brent C
AU  - Ruby BC
FAU - Stewart, Laura K
AU  - Stewart LK
FAU - Baker, Lindsay B
AU  - Baker LB
FAU - Zachwieja, Jeffrey J
AU  - Zachwieja JJ
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Med Sci Sports Exerc
JT  - Medicine and science in sports and exercise
JID - 8005433
RN  - 0 (Dietary Carbohydrates)
RN  - 0 (Lactates)
SB  - IM
MH  - Adult
MH  - Athletic Performance/*physiology
MH  - Beverages
MH  - Bicycling/*physiology
MH  - Dietary Carbohydrates/*administration & dosage
MH  - Dose-Response Relationship, Drug
MH  - Humans
MH  - Lactates/blood
MH  - Male
MH  - Physical Endurance/*drug effects
MH  - Regression Analysis
MH  - Running/*physiology
MH  - Swimming/*physiology
EDAT- 2012/09/13 06:00
MHDA- 2013/06/26 06:00
CRDT- 2012/09/13 06:00
PHST- 2012/09/13 06:00 [entrez]
PHST- 2012/09/13 06:00 [pubmed]
PHST- 2013/06/26 06:00 [medline]
AID - 10.1249/MSS.0b013e31827205d1 [doi]
PST - ppublish
SO  - Med Sci Sports Exerc. 2013 Feb;45(2):336-41. doi: 10.1249/MSS.0b013e31827205d1.