INTRODUCTION
muscle hypertrophy
INFLAMMATION
The beneficial effects of exercise on health span and lifespan are among the most well‐documented scientific findings in health science research (Aune et al., Given that many beneficial effects of exercise require repeated bouts over time to manifest, this represents an opportunity for discovery. Consider for example the inappropriate conclusions that could be drawn when studying the effects of a single bout of exercise on muscle hypertrophy, strength, or inflammation. The beneficial effects of exercise on biological aging is likely most apparent when studied over time.The central theme of molecular biology holds that a cell's function and status are dictated by the specific sets of genes undergoing transcription at any given time, and to what degree these processes are occurring (O'Brien et al., As high‐throughput RNA sequencing becomes more commonplace, gene expression‐based predictive models have emerged. Some of these models are designed to predict biological age (Meyer & Schumacher, The biological age prediction field is diverse and rapidly evolving, with models composed of various inputs (Cesari et al., The effect of exercise on various biological age predictors is inconsistent. Most experimental studies that examine the relationship between exercise and biological age use telomere length as their primary biomarker of aging. These results are mixed, with positive relationships, U‐shaped relationships, and no relationship all being reported (Sellami et al., Fewer studies have been performed using epigenetic alteration, such as DNA methylation or histone methylation/acetylation as an outcome measure. Of those that have been performed, various types of exercise have been shown to induce widespread changes in the methylome and associated gene expression (Barrès et al., To the authors' knowledge, only two lifestyle modification trials have utilized a next generation predictor of biological age in humans, such as an epigenetic clock (Fiorito et al., The trial described here aims to address this by utilizing high‐throughput RNA sequencing to explore the effects of 12 high‐intensity interval training (HIIT) sessions on biological age as measured by a blood mRNA‐based “transcriptomic clock” (Peters et al., To confirm previously observed effects of HIIT on various physiological parameters (Gu et al., 