Exercise-induced coronary angiogenesis: a review.

Numerous studies have examined the effects of exercise training on coronary angiogenesis. Although the conclusions drawn from these studies are sometimes conflicting, variabilities in training (magnitude, type and intensity), age and other factors need to be closely examined. Most studies on young animals indicate that capillary growth occurs providing that the training intensity is appropriate. Furthermore, there is evidence that growth of arteries and resistance vessels can occur as indicated by 1) direct measurements of vessels and 2) calculation of minimal coronary vascular resistance during pharmacologically induced vasodilation. Although the mechanism(s) underlying exercise-induced angiogenesis is unknown, mechanical events associated with increased flow and/or increased venous return, as well as resting bradycardia may serve to trigger growth factors involved in mitogenic, migratory, and tube formation of endothelial cells. In contrast, exercise training per se does not appear to enhance collateral vessel growth. However, there is evidence that collateral growth is accelerated with training in animals with coronary artery occlusion.