Breathing Exercises...?

[Debra]

I'm a really good runner and I could run for miles but my lungs never agree with my legs. I get tired easily when I run. Can you tell me some excises I can do to expand my lungs and how many times I should do them a day? Thank you!! P.S I can't go into yoga or anything but if you have links on youtube or something that would be great!!! <3