Acute Endurance Exercise Amends the Circulating MicroRNA Profile in Response to Exercise Dosage

Regular exercise, particularly continuous endurance activity, is known to help prevent and manage various chronic conditions. It remains unknown which cellular and molecular mechanisms underpin the adaptive response to exercise, despite new research suggesting that epigenetic mechanisms, particularly microRNAs (miRNAs), may play a role in the formation and regulation of exercise-related alterations. A "fitness score" was created by integrating the analysis of miRNAs as epigenetic biomarkers, genetic predispositions, and food and supplement consumption in order to gauge an individual's response to diet, exercise, and metabolic effects.

In response to a four-week sports intervention, we employed qPCR analysis to investigate genetic and epigenetic markers, including miR-21 and miR-146a, in capillary blood from 10 participants (mean age: 33 years, comprising 66.1% females and 33.9% males). A healthy, ageand sex-matched control group (n = 10) that did not receive any intervention was also used to study these biomarkers.

Significant differences (P < 0.05) were observed in the relative expression levels of two microRNAs, miR-21 and miR-146a. During the training period, expression levels increased in nine out of ten participants. Specifically, miR-21 expression rose from 1.125 ± 0.113 to 1.164 ± 0.205, and miR-146a expression increased from 1.103 ± 0.054 to 1.210 ± 0.217 following the intervention.

Our research reveals that, during a 4-week training cycle, the levels of specific microRNAs, such as miR-21 and miR-146a, fluctuate. The levels of these miRNAs significantly increased after the intense training session.

Our findings suggest that a comprehensive examination of multiple biomarkers (miRNAs) may provide insights into a person's body composition, potential recovery, training adaptations, fitness, and dietary requirements. We demonstrated that these biomarkers can also be tested using a less invasive technique, in contrast to the majority of research that uses muscle biopsies.