Adaptations to skeletal muscle with endurance exercise training in the acutely fed versus overnight-fasted state

J Sci Med Sport. 2010 Jul;13(4):465-9. doi: 10.1016/j.jsams.2010.03.002. Epub 2010 May 7.


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.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adaptation, Physiological / physiology*
  • Adult
  • Citrate (si)-Synthase / metabolism
  • Fasting / physiology*
  • Female
  • Glycogen / metabolism
  • Humans
  • Male
  • Muscle, Skeletal / physiology*
  • Oxygen Consumption
  • Physical Endurance / physiology*
  • Young Adult


  • Glycogen
  • Citrate (si)-Synthase