Molecular responses in abdominal subcutaneous adipose tissue after a session of endurance exercise: effects of exercise intensity.

The primary aim of this study was to compare the acute effects of three exercise intensities on abdominal subcutaneous adipose tissue (aSAT) transcriptome in regular exercisers. A total of 45 adults who exercise regularly were assigned to perform a single session of either low-intensity continuous (LOW; 60 min at 30% VO₂max; n = 15), moderate-intensity continuous (MOD; 45 min at 65% VO₂max; n = 15) or high-intensity interval exercise (HIGH; 10 × 1 min at 90% VO₂max interspersed with 1 min active recovery; n = 15). aSAT biopsy samples were collected before and 1.5 h after the exercise session for bulk RNA sequencing and targeted protein immunoassays. HIGH upregulated genes were involved in angiogenesis, protein secretion and insulin signalling pathways, whereas MOD and LOW upregulated genes regulated extracellular matrix (ECM) remodelling, ribosome biogenesis and oxidative phosphorylation pathways. Exercise-induced changes in aSAT clock genes, ERK protein phosphorylation and circulating cytokines were similar after all three exercise treatments. Network analysis identified exercise-responsive gene clusters linked to cardiometabolic health traits. Cell-type analysis highlighted a heterogeneous response of aSAT cell types to exercise, with distinct patterns observed across exercise intensities. Collectively, our data characterize early responses in aSAT after a single session of exercise. Because adaptations to exercise training stem from an accrual of responses after each session of exercise, these early responses to exercise are likely important contributors to the long-term structural and functional changes that occur in adipose tissue in response to exercise training. KEY POINTS: Chronic adaptations in adipose tissue from regular exercise support cardiometabolic health, but the acute molecular triggers of these adaptations remain unclear. We show that acute exercise alters gene expression, along with ERK phosphorylation in adipose tissue of regular exercisers. Exercise intensity shapes the transcriptomic response: high-intensity exercise induces inflammatory, cytokine and genes, whereas lower intensities upregulate genes involved in protein translation and oxidative phosphorylation. Network and cell-type analyses highlight intensity-specific adipose responses, revealing gene modules linked to health traits and differential engagement of adipocyte subpopulations.