I enjoy running, but about halfway through my runs I always get an awful cramp in my left side. My running partners tell me to just run it out, or pinch my right side, or eat more bananas for the potassium. What do you think?

--margy

Running gives me terrible side aches. Can you tell me why this happens?
--joanna

That side ache or cramp is what is commonly called a "stitch," margy and joanna -- a cramp or spasm in the diaphragm. Your diaphragm is a muscle that stretches across your chest cavity below your lungs. It expands downward when we inhale and contracts upward when we exhale. Stitches can occur when we run too fast or breathe rapidly without getting enough air into our lungs during inhalation, or when we don't expel enough air during exhalation. They are not the result of having too little potassium or of being dehydrated, as leg cramps often are.

When we run at a comfortable pace -- a pace that allows us to carry on a conversation -- breathing is rarely a problem. As the pace increases, we need more oxygen and our breathing becomes more rapid. (When I'm training on my bike with a group, I can always tell the people who are struggling because they can't keep up the snappy patter and witty repartee. On steep hills, everybody is quiet.)

Pressing on your side helps relieve the discomfort of a stitch. Learning a technique called "belly breathing" is a way to counteract stitches and prevent them from occurring.

To belly breathe, contract your abdominal muscles and pull your stomach in as you exhale. Force as much air as possible out of your lungs, and then inhale as much as you can. As you inhale, you should feel your abs swell as your diaphragm stretches downward, allowing your lungs to expand fully. This technique is similar to the diaphragmatic breathing that singers like Jessye Norman use to hold a note for a long time.

If I feel a stitch coming on, I begin belly breathing and continue until the pace slows. When I can anticipate a hard effort, like a long, steep incline, I start belly breathing before I even get to the climb. I focus primarily on the exhalation and the contraction of my abs. The sound I make as I force the air is actually quite calming to me, and I use it like a mantra to help get me through the hard part of a ride. (To other people, I sound like an anemic steam engine.)

To use this technique successfully, you need strong, supple abdominal muscles (handy things to have anyway), so check the Fit by Friday archives for some ab routines. Or, get Stronger Abs and Back by Dean and Greg Brittenham (Human Kinetics).

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