3 research outputs found
No attenuation of gastric distress or benefit to performance with adaptation to octanoate-rich esterified oils in female cyclists
Effect of graded fructose coingestion with maltodextrin on exogenous 14C-fructose and 13C-glucose oxidation efficiency and high-intensity cycling performance
The ingestion of solutions containing carbohydrates with different
intestinal transport mechanisms (e.g., fructose and glucose) produce
greater carbohydrate and water absorption compared with singlecarbohydrate
solutions. However, the fructose-ingestion rate that
results in the most efficient use of exogenous carbohydrate when
glucose is ingested below absorption-oxidation saturation rates is
unknown. Ten cyclists rode 2 h at 50% of peak power then performed
10 maximal sprints while ingesting solutions containing 13C-maltodextrin
at 0.6 g/min combined with 14C-fructose at 0.0 (No-Fructose),
0.3 (Low-Fructose), 0.5 (Medium-Fructose), or 0.7 (High-Fructose)
g/min, giving fructose:maltodextrin ratios of 0.5, 0. 8, and 1.2. Mean
(percent coefficient of variation) exogenous-fructose oxidation rates
during the 2-h rides were 0.18 (19), 0.27 (27), 0.36 (27) g/min in
Low-Fructose, Medium-Fructose, and High-Fructose, respectively,
with oxidation efficiencies (�oxidation/ingestion rate) of 62–52%.
Exogenous-glucose oxidation was highest in Medium-Fructose at 0.57
(28) g/min (98% efficiency) compared with 0.54 (28), 0.48 (29), and
0.49 (19) in Low-Fructose, High-Fructose, No-Fructose, respectively;
relative to No-Fructose, only the substantial 16% increase (95%
confidence limits �16%) in Medium-Fructose was clear. Total exogenous-
carbohydrate oxidation was highest in Medium-Fructose at
0.84 (26) g/min. Although the effect of fructose quantity on overall
sprint power was unclear, the metabolic responses were associated
with lower perceptions of muscle tiredness and physical exertion, and
attenuated fatigue (power slope) in the Medium-Fructose and High-
Fructose conditions. With the present solutions, low-medium fructose-
ingestion rates produced the most efficient use of exogenous
carbohydrate, but fatigue and the perception of exercise stress and
nausea are reduced with moderate-high fructose doses