Final answer:
Blood vessels dilate in active skeletal muscles and constrict in other organs during exercise. Regular aerobic training leads to adaptations in blood vessels that improve cardiovascular health.
Step-by-step explanation:
During exercise, blood vessels respond by dilating in the skeletal muscles, heart, lungs, liver, and integument, while vasoconstriction occurs in the vessels leading to the kidneys and most of the digestive and reproductive organs.
This selective vasodilation allows for increased blood flow to the active muscles and organs.
In addition, regular aerobic training can lead to adaptations in the blood vessels, such as increased capillarization and improved endothelial function, which enhance oxygen delivery and improve overall cardiovascular health.