Glucose ingestion during endurance training does not alter adaptation

Feb 21, 2009Journal of applied physiology (Bethesda, Md. : 1985)

Taking glucose while endurance training does not change how the body adapts

AI simplified

Circadian Biology on OpenScience ↗PubMed ↗DOI ↗

Abstract

Glucose ingestion during training does not affect adaptations in muscle metabolism or performance.

Nine male subjects trained one leg with a glucose solution and the other with a placebo over 10 weeks.
Endurance training resulted in a 14% increase in peak power and a 30% increase in time to fatigue.
Citrate synthase and beta-hydroxyacyl-CoA dehydrogenase activity increased, along with greater glycogen content post-training.
Fatty acid oxidation rates changed following training, with a 16.4% increase during exercise and a 30.4% decrease after exercise.
No significant differences were observed between the glucose and placebo conditions regarding metabolic adaptations or performance.

AI simplified

Glucose ingestion during exercise attenuates activation of metabolic enzymes and expression of important transport proteins. In light of this, we hypothesized that glucose ingestion during training would result in 1) an attenuation of the increase in fatty acid uptake and oxidation during exercise, 2) lower citrate synthase (CS) and beta-hydroxyacyl-CoA dehydrogenase (beta-HAD) activity and glycogen content in skeletal muscle, and 3) attenuated endurance performance enhancement in the trained state. To investigate this we studied nine male subjects who performed 10 wk of one-legged knee extensor training. They trained one leg while ingesting a 6% glucose solution (Glc) and ingested a sweetened placebo while training the other leg (Plc). The subjects trained their respective legs 2 h at a time on alternate days 5 days a week. Endurance training increased peak power (P(max)) and time to fatigue at 70% of P(max) approximately 14% and approximately 30%, respectively. CS and beta-HAD activity increased and glycogen content was greater after training, but there were no differences between Glc and Plc. After training the rate of oxidation of palmitate (R(ox)) and the % of rate of disappearance that was oxidized (%R(dox)) changed. %R(dox) was on average 16.4% greater during exercise after training whereas, after exercise %R(dox) was 30.4% lower. R(ox) followed the same pattern. However, none of these parameters were different between Glc and Plc. We conclude that glucose ingestion during training does not alter training adaptation related to substrate metabolism, mitochondrial enzyme activity, glycogen content, or performance.

Full Text

Full text is available at the source.

View full text ↗

Glucose ingestion during endurance training does not alter adaptation

Abstract

Full Text

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief

Abstract

Full Text

Related papers

You found one interesting study. We’ll send the next 7.

what lands in your inbox each week:

Recent issues from the circadian biology brief