I've read several fitness articles mentioning redirected blood flow to muscles that are in use. However, they never mention how it works. Is it local and specific to the muscles in use? Or, for example, I guess more blood has to flow through the entire arm if I am training my forearms..? So, won't the entire arm benefit to a certain extent?
I did some research and discovered the vascular shunt mechanism through the opening and closing of capillary sphincters. However, I cannot find any resources discussing how local this effect is. So, as an example, how much does blood flow to the arm improve if someone is training their forearm for six months?