Effects of continuous and intermittent aerobic exercise upon mRNA expression of metabolic genes in human skeletal...

It is known that intermittent aerobic exercise training program is more efficient for the improvement of aerobic performance than continuous one but molecular mechanisms of such effects are purely understood. The aim of the present study was to compare gene expression of mitochondrial biogenesis regulators (peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), mitochondrial transcription factors A (TFAM) and B2 (TFB2M) and genes involved in exercise-induced catabolic events (forkhead box O1 (FOXO1) and Atrogin-1) in human skeletal muscle after single continuous (CE) and intermittent (IE) aerobic exercise sessions, equalized thoroughly in duration and mean power output.

Twelve physically active males performed CE (workload at lactate threshold [LT], 50 min) or IE ([3 min 81% LT+2 min 125% LT]x10). The biopsies were taken from m. vastus lateralis before and 1 h, 3 h, 5 h after the exercise.

The IE induced a 2-fold greater increase of PGC-1α and TFAM gene expression after 3 h and 5 h of recovery than CE. The increments of Atrogin-1 mRNA abundance were observed 3 and 5 h after IE only. The increments in FOXO1 mRNA level were revealed 1 h and 3 h after the IE and 3 h after the CE.

The results of the study suggest that higher potential of IE for the improvement of mitochondrial biogenesis than CE associated with more pronounced increase of PGC-1α and TFAM mRNA expression. Along with that, IE induces a higher increment of expression of FOXO1 and Atrogin-1 genes involved with exercise-induced catabolic events compared to CE.