Type, Duration, and Intensity of Physical Exercise Modulate FNDC5/Irisin Expression in the Hippocampus

Introduction: Physical exercise can activate important biochemical processes in the human body, one of which is a myokine called irisin. Objective: This review aims to identify the effect of exercise on the expression of FNDC5/irisin, a myokine secreted by skeletal muscles that is produced in response to physical activity. This hormone provides a protective function in the central nervous system, specifically the hippocampus. The effects of exercise on the brain are well known, but the duration, intensity and type of exercise as well as the underlying molecular mechanisms are not fully understood. This review will focus on Fibronectin type III domain-containing protein 5 (FNDC5) and its secreted form, myokine “irisin” with a mechanism of action in the hippocampus and the effect of exercise on irisin expression. Method: A literature search was performed on several databases (PubMed, Scopus, and Sciencedirect) on the impact of training on irisin, resulting in 17 articles. Results: This review shows that physical exercise increases plasma irisin levels in humans and brains in rats, including the hippocampus. Discussion; The relationship between exercise, FNDC5 (the gene that encodes irisin), and the hippocampus is an area of active research. FNDC5/irisin is a protein that has gained attention for its potential role in mediating some of the beneficial effects of exercise on the brain, including the hippocampus. Conclusion: Irisin is expressed in plasma and hippocampus as a result of physical exercise that depends on the type, intensity, and duration of exercise that functions in the brain.