Adaptations to skeletal muscle with endurance exercise training in the acutely fed versus overnight-fasted state.
Minimising carbohydrate (CHO) status in the peri-training period may accelerate the training adaptations normally observed. The aim of this study was to compare adaptations to endurance training undertaken in the acutely CHO fed and overnight-fasted states. Eight female and six male untrained, healthy participants: aged 26.6+/-5.8 years (mean+/-SD); height 174.7+/-7.6 cm; weight 75.3+/-11.4 kg; VO(2max) 3.48+/-0.67 l/min; were randomly divided into two training groups and undertook four weeks of five days per week endurance cycle ergometer training in either the overnight-fasted (FAST) or acutely fed (FED) state. FAST training had no effect on RER or plasma glucose, lactate and FFA concentrations during subsequent submaximal exercise. Training-induced changes in Vastus lateralis citrate synthase (CS) and 3-hydroxy-CoA dehydrogenase (HAD) activities were not different between training groups (P=0.655 and 0.549, respectively), but when the effect of gender was considered, men responded better to FAST and women responded better to FED. The FAST group showed a significantly greater training-induced increase in VO(2max) and resting muscle glycogen concentration than FED (P=0.014 and P=0.047 respectively), but there was no gender interaction. In conclusion, these results suggest that (a) meal ingestion prior to daily exercise can modify some of the exercise training-induced adaptations normally seen with endurance training compared to when daily exercise is undertaken in the overnight-fasted state; and (b) the extent of these adaptations in skeletal muscle differ slightly between men and women.
Stannard
Stephen R
SR
Institute of Food Nutrition and Human Health, Massey University, Palmerston North, New Zealand. S.Stannard@massey.ac.nz
Buckley
Alex J
AJ
Edge
Johann A
JA
Thompson
Martin W
MW
D000222:Adaptation, Physiological / Q000502:physiology*; D000328:Adult; D002950:Citrate (si)-Synthase / Q000378:metabolism; D005215:Fasting / Q000502:physiology*; D005260:Female; D006003:Glycogen / Q000378:metabolism; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D010101:Oxygen Consumption; D010807:Physical Endurance / Q000502:physiology*; D055815:Young Adult
D006003:Glycogen; D002950:Citrate (si)-Synthase