Circulating microRNAs and physical activity: Impact in diabetes.

The term "ci-miRNAs," or "circulating microRNAs," refers to extracellular microRNAs (miRNAs) that exist outside of cells and can be detected in various bodily fluids, including blood, saliva, urine, and breast milk. These ci-miRNAs play a role in regulating gene expression and are mainly recognized for their functions beyond the cell, serving as signaling molecules in the blood. Researchers have thoroughly investigated the roles of these circulating miRNAs in various diseases. The capacity to detect and quantify ci-miRNAs in bodily fluids suggests their potential as biomarkers for monitoring several health conditions, including cancer, heart disease, brain disorders, and metabolic disorders, where fluctuations in miRNA levels may correlate with different physiological and pathological states. Current methods enable researchers to identify and measure miRNAs in these fluids, facilitating the exploration of their roles in health maintenance and disease resistance. Although research on ci-miRNAs is ongoing, recent studies focus on uncovering their significance, assessing their viability as biomarkers, and clarifying their functions. However, our understanding of how various types, intensities, and durations of exercise influence the levels of these miRNAs in the bloodstream is still limited. This section seeks to provide an overview of the changes in ci-miRNAs in response to exercise.