PMID- 10870867
OWN - NLM
STAT- MEDLINE
DCOM- 20001019
LR  - 20181113
IS  - 0112-1642 (Print)
IS  - 0112-1642 (Linking)
VI  - 29
IP  - 6
DP  - 2000 Jun
TI  - Oxidation of carbohydrate feedings during prolonged exercise: current thoughts, 
      guidelines and directions for future research.
PG  - 407-24
AB  - Although it is known that carbohydrate (CHO) feedings during exercise improve 
      endurance performance, the effects of different feeding strategies are less 
      clear. Studies using (stable) isotope methodology have shown that not all 
      carbohydrates are oxidised at similar rates and hence they may not be equally 
      effective. Glucose, sucrose, maltose, maltodextrins and amylopectin are oxidised 
      at high rates. Fructose, galactose and amylose have been shown to be oxidised at 
      25 to 50% lower rates. Combinations of multiple transportable CHO may increase 
      the total CHO absorption and total exogenous CHO oxidation. Increasing the CHO 
      intake up to 1.0 to 1.5 g/min will increase the oxidation up to about 1.0 to 1.1 
      g/min. However, a further increase of the intake will not further increase the 
      oxidation rates. Training status does not affect exogenous CHO oxidation. The 
      effects of fasting and muscle glycogen depletion are less clear. The most 
      remarkable conclusion is probably that exogenous CHO oxidation rates do not 
      exceed 1.0 to 1.1 g/min. There is convincing evidence that this limitation is not 
      at the muscular level but most likely located in the intestine or the liver. 
      Intestinal perfusion studies seem to suggest that the capacity to absorb glucose 
      is only slightly in excess of the observed entrance of glucose into the blood and 
      the rate of absorption may thus be a factor contributing to the limitation. 
      However, the liver may play an additional important role, in that it provides 
      glucose to the bloodstream at a rate of about 1 g/min by balancing the glucose 
      from the gut and from glycogenolysis/gluconeogenesis. It is possible that when 
      large amounts of glucose are ingested absorption is a limiting factor, and the 
      liver will retain some glucose and thus act as a second limiting factor to 
      exogenous CHO oxidation.
FAU - Jeukendrup, A E
AU  - Jeukendrup AE
AD  - Human Performance Laboratory, School of Sport and Exercise Sciences, University 
      of Birmingham, Edgbaston, England. a.e.jeukendrup@bham.ac.uk
FAU - Jentjens, R
AU  - Jentjens R
LA  - eng
PT  - Journal Article
PT  - Review
PL  - New Zealand
TA  - Sports Med
JT  - Sports medicine (Auckland, N.Z.)
JID - 8412297
RN  - 0 (Dietary Carbohydrates)
RN  - 30237-26-4 (Fructose)
RN  - 9005-79-2 (Glycogen)
SB  - IM
MH  - Dietary Carbohydrates/*metabolism
MH  - Exercise/*physiology
MH  - Fructose/metabolism
MH  - Gastric Emptying/physiology
MH  - Glycogen/metabolism
MH  - Humans
MH  - Intestinal Absorption/physiology
MH  - Muscle, Skeletal/metabolism
MH  - Osmolar Concentration
MH  - Oxygen Consumption
MH  - Physical Endurance/*physiology
MH  - Time Factors
RF  - 88
EDAT- 2000/06/28 11:00
MHDA- 2000/10/21 11:01
CRDT- 2000/06/28 11:00
PHST- 2000/06/28 11:00 [pubmed]
PHST- 2000/10/21 11:01 [medline]
PHST- 2000/06/28 11:00 [entrez]
AID - 10.2165/00007256-200029060-00004 [doi]
PST - ppublish
SO  - Sports Med. 2000 Jun;29(6):407-24. doi: 10.2165/00007256-200029060-00004.