Thoracic aortic dilatation is a progressive condition that results from aging and many pathological conditions (i.e., connective tissue, inflammatory, shear stress disorders, severe valvular heart disease) that induce degenerative changes in the elastic properties, leading to the loss of elasticity and compliance of the aortic wall. Mild aortic root enlargement may be also observed in athletes and is considered as a normal adaptation to regular exercise training. On the other hand, high-intensity physical activity in individuals with a particular genetic substrate, such as those carrying gene variants associated with Marfan syndrome or other inherited aortopathies, can favor an excessive aortic enlargement and trigger an acute aortic dissection. The evaluation of the aortic valve and aortic root diameters, as well as the detection of a disease-causing mutation for inherited aortic disease, should be followed by a tailored decision about sport eligibility. In addition, the risk of aortic complications associated with sport in patients with genetic aortic disease is poorly characterized and is often difficult to stratify for each individual athlete. This review aims to describe the relationship between regular physical activity and aortic dilation, focusing on patients with bicuspid aortic valve and inherited aortic disease, and discuss the implications in terms of aortic disease progression and sport participation.