Resumen de Similar Expression of Oxidative Genes after Interval and Continuous Exercise
Li Wang, Niklas Psilander, Michail Tonkonogi, Shuzhe Ding, Kent Sahlin
Purpose: There is a debate whether interval or traditional endurance training is the most effective stimulus of mitochondrial biogenesis. Here, we compared the effects of acute interval exercise (IE) or continuous exercise (CE) on the muscle messenger RNA (mRNA) content for several genes involved in mitochondrial biogenesis and lipid metabolism.
Methods: Nine sedentary subjects cycled for 90 min with two protocols: CE (at 67% V[spacing dot above]O2max) and IE (12 s at 120% and 18 s at 20% of V[spacing dot above]O2max). The duration of exercise and work performed with CE and IE was identical. Muscle biopsies were taken before and 3 h after exercise.
Results: There were no significant differences between the two exercise protocols in the increases in V[spacing dot above]O2 and HR, the reduction in muscle glycogen (35%-40% with both protocols) or the changes in blood metabolites (lactate, glucose, and fatty acids). The mRNA content for major regulators of mitochondrial biogenesis [peroxisome proliferator-activated receptor (PPAR) [gamma] coactivator 1[alpha] (PGC-1[alpha]), PGC-1-related coactivator, PPAR/[delta]] and of lipid metabolism [pyruvate dehydrogenase kinase isozyme 4 (PDK4)] increased after exercise, but there was no significant difference between IE and CE. However, the mRNA content for several downstream targets of PGC-1[alpha] increased significantly only after CE, and mRNA content for nuclear respiratory factor 2 was significantly higher after CE (P < 0.025 vs IE).
Conclusions: The present findings demonstrate that, when the duration of exercise and work performed is the same, IE and CE influence the transcription of genes involved in oxidative metabolism in a similar manner.
