Breathing while running should be done with the diaphragm instead of the chest. Breathe in a pattern with your steps. One common breathing pattern involves inhaling for two steps, then exhaling for two steps.
The amount of steps for inhaling and exhaling don't have to be equal. Another popular pattern is inhaling for three steps, then exhaling for two while running at an easy pace. When the intensity is increased, inhale for two steps and exhale for one.
To practice breathing with your diaphragm, lie on your back and breathe deeply through the mouth. You should feel each breath in your stomach. Begin walking while breathing this way, then progress to jogging and running.
Another way to practice breathing is to perform Pilates exercises such as the swan and the standing chest expansion. The swan is performed by lying face down with your palms directly under your shoulders and looking downward to align the neck and spine. Inhale while lifting your upper body off the mat and pressing your palms into the ground. Exhale while lowering yourself towards the ground. The standing chest expansion is performed by standing with both arms hanging at your sides, then sweeping the arms out and up as you inhale. The arms should end above the head with both palms facing each other. Exhale as the arms are swept back down.