TY - JOUR
T1 - Glucose ingestion during endurance training does not alter adaptation
AU - Akerstrom, Thorbjorn C.A.
AU - Fischer, Christian P.
AU - Plomgaard, Peter
AU - Thomsen, Carsten
AU - Van Hall, Gerrit
AU - Pedersen, Bente Klarlund
PY - 2009/6/1
Y1 - 2009/6/1
N2 - 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 β-hydroxyacyl-CoA dehydrogenase (β-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 ∼14% and ∼30%, respectively. CS and β-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.
AB - 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 β-hydroxyacyl-CoA dehydrogenase (β-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 ∼14% and ∼30%, respectively. CS and β-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.
KW - Metabolism
KW - Performance
KW - Skeletal muscle
UR - http://www.scopus.com/inward/record.url?scp=66749145004&partnerID=8YFLogxK
U2 - 10.1152/japplphysiol.91534.2008
DO - 10.1152/japplphysiol.91534.2008
M3 - Article
C2 - 19228984
AN - SCOPUS:66749145004
VL - 106
SP - 1771
EP - 1779
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
SN - 8750-7587
IS - 6
ER -