Exercise and Artery Function in Twins: Sex Differences in a Cross-Over Trial

Physical activity reduces cardiovascular risk, partly via direct effects on the arterial wall. We hypothesized that vascular function responses would be modality-specific, sex-dependent, and express a high degree of heritability. We recruited 90 same-sex twins (31 monozygotic, 14 dizygotic dizygotic pairs; 25.8±6.0 years) and randomized 70 (25 monozygotic, 10 dizygotic) to complete, as pairs, 3 months each of resistance and endurance training, separated by a 3-month washout. Brachial artery flow-mediated (FMD%) and glyceryl-trinitrate induced dilation (GTN%) both increased following endurance (FMD%: ∆1.46%,