Aerobic exercise can delay aging and extend lifespan, but its specific mechanism still remains unclear. One popular theory is that with age and the cell division times increasing, DNA damage will inevitably accumulate, leading to dysfunction and failure of various tissues and organs, which will eventually lead to aging. Thus, repairing damaged DNA is a key strategy to extend lifespan. Excision repair cross-complementary gene 1 (ERCC1) is a DNA repair enzyme that recognizes, excises and repairs damaged DNA. Defects or reduced activity of the enzyme can lead to DNA damage accumulation. This study provides that aerobic exercise can significantly extend rats' lifespan and increase the expression of ERCC1 in heart, brain, liver and kidney. Therefore, based on our experiments, we propose the following scientific hypothesis: aerobic exercise can up-regulate the expression of ERCC1 and then may reduce DNA damage accumulation to maintain genomic integrity and stability, thereby delaying aging and prolonging lifespan in humans.