How do I avoid getting "side stitches" while running?

I had been wondering about this and was eager to read the first answer. I know how to indirectly contract the diaphragm three-dimensionally, but I never knew that you could contract it isometrically at will. A google search got no result.

Could you please explain how to do this?

Karin, this is how is done, you pinch your nose with your fingers and don't let any air out and at the same time you are trying to exhale out of your mouth but, dont let any air out of the mouth either, do it for 10 reps. Again the puropose is to try to exhale through your nose and mouth at the same time, but you don't. I hope that explains it? This technique is a Physical Therapy Technique, and also works great after any impact that causes you to lose your breath. Also, it will get rid of a stich on your side, instantly.

Another simple thing to do is blow air out as long as you possibly can. It's simple layman's thing to tell a client.

You can val salva away a "side stitch"? I am sooooo trying this! I relax my breathing and tip my head back slightly to open the air passage wide, allowing the air to "fall" into and out of the lungs with little effort gets it to go away most of the time.

I breathe in through my nose as deeply as I can while running and exhale through my mouth and that usually helps