Nitric oxide synthase 3 (coded by the NOS3 gene) is an enzyme that facilitates the production of nitric oxide (NO). NO is involved in the widening of blood vessels by relaxation of the smooth muscle cells within their walls, which increases blood flow. Variations in the NOS3 gene may affect the predisposition for power/strength performance. These variations may also influence the beneficial effects induced by exercise, such as a lowering of blood triglycerides levels.
Source: 1000 Genome Project. Global averages for both sexes