Raw Data

Regular aerobic exercise decreases the risk of metabolic diseases; however, reduced physical activity may attenuate these beneficial adaptations. This study investigated the influence of a single day of reduced activity on the skeletal muscle transcriptome (RNASeq) and systemic metabolism surrounding an acute bout of aerobic exercise. Utilizing a crossover design, subjects (n=9 [7M, 2F], 24±1y) exercised at 65% VO2max for 60-minutes following a day of reduced activity (IN; 3,581±1,185 steps) and normal activity (A; 11,069±3,631 steps). RNAseq from skeletal muscle biopsies were taken before and 4-hours post-exercise. Respiratory gas exchange analysis was completed at 20, 40, and 60 minutes of exercise. Blood samples for select metabolites were collected before, during, and throughout the 4-hour recovery. Inactivity resulted in nine Differentially Expressed Genes (DEG) at rest, while exercise altered 793 and 1,403 genes in A and IN, respectively. Gene set enrichment analysis revealed an interaction of exercise and trial, which were related to inflammation, metabolism, cell cycle, and innate immunity. Respiratory exchange ratio (0.93±0.04 vs. 0.91±0.03; p<0.05) and carbohydrate utilization (2.16±0.79 vs. 1.96±0.72 g/min; p=0.09) were higher in the IN vs. A trial at 60-minutes of exercise. Triglycerides were higher in the IN trial (p<0.05), with no differences between trials observed in other measured metabolites. These findings indicate that a single day of reduced physical activity can elicit modest but significant changes in the metabolic and transcriptomic exercise response. Such alterations have implications for exercise guidelines and underscore the importance of controlling for daily step count when assessing exercise responses.