What is the RIGHT way to breath when running? ?

Dont listen to either of the people above. Breathe in through your mouth and nose, and out through both your mouth and nose. To run properly you need to be getting in as much oxygen as possible, so why on earth would you wanto cut off the most efficient way to take in oxygen by closing your mouth? It is a bigger hole, it can take in more oxygen in less time. If you dont believe me, try running while holding your breath. Its not easy. Try breathing as deeply as possible through your nose, and then through your mouth. Which way do you get more air in? Simple logic, breathe the way that feels natural.

I'm a high school track athlete and my coach always says to slow down your breathing...

When you first start, try to keep breathing through your nose for as long as you can, the move on to breathing in through your nose and out through your mouth. You might be getting light headed partially due to dehydration so make sure to take a water bottle with you. Also make sure you take deep breaths, not shallow ones. Try doing some breathing exercises before you go running, lie down on the floor and put a book (a light one) on your stomach and see if when you breathe in you can lift the book and when you breathe out let the book come down slowly.

I agree with the person above me. In your nose and out your mouth.