Abstract
This presentation summarizes the experimental data on the oxidation of exogenous substrates
using isotopic labelling: glucose, fructose, maltodextrins, glucose polymers, starch
and FFA. The two main determining factors for the oxidation of exogenous substrates
are in this order: power output and amount of ingested substrates. The largest oxidation
of exogenous substrate is observed for glucose, maltodextrins, Polycose, and starch.
For exercises of one hour duration or more, the average rate of oxidation of these
compounds can reach up to 0.5 g/min, which agrees with the indirect estimation of
Coyle et al. Fructose is oxidized at a lower rate, except when it is taken before
the exercise period. FFA are only oxidized to a small extent.
Key words
Carbohydrates - free fatty acids - energy metabolism - prolonged exercise
