Impact of exercise and fasting on mitochondrial regulators in human muscle.

OBJECTIVES

To investigate the impact of acute energetic stress (acute HIIE and fasting) on , , , , and in human skeletal muscle.

METHODS

The current study performed secondary analyses using muscle biopsy samples from two previously published studies: study 1) leg muscle biopsies from nine men and eight women were obtained pre and 3 h following acute high-intensity interval cycling exercise (HIIE); study 2) leg muscle biopsies were obtained from nine men pre-, during, and post-an 8 h fast with or without 2 h of arm ergometer exercise. RT-PCR was performed on samples from each study to determine the mRNA expression of , , , , and . Additionally, we retrieved data from meta-analyzed human muscle gene expression using the publicly available database MetaMex.

RESULTS

(p<0.01, d=1.98) and (p<0.01, d=1.36) mRNA expression significantly increased while (p≤0.05, d=0.70) decreased following HIIE. Significant decreases in and mRNA expression were observed following an 8 h fast. Our MetaMex analyses revealed significant increases (p<0.05) in and  expression following aerobic and resistance exercise, and in expression following resistance exercise.

CONCLUSIONS

Our data indicate that acute HIIE stimulates increases in and and decreases in mRNA expression in human skeletal muscle. Additionally, a short term (8 h) fast reduced the mRNA expression of the transcriptional regulators and  - potentially as a mechanism of decreasing mitochondrial biogenesis to reduce energy expenditure during a period of restricted energy availability.