The body needs an immense amount of oxygen during physical activity, so many runners try to develop the best breathing technique for running that will maximize oxygen intake to stimulate blood flow and body function. Unfortunately, there is no one breathing technique for running that will be best for everyone, so it will be necessary to try several techniques before finding the one that works best for the individual runner. The general idea, however, will remain the same: it is important to maximize intake through the mouth and nose if possible, and it is best to breathe with the diaphragm rather than the chest.
A commonly-used breathing technique for running involves taking in oxygen in both the nose and the mouth, and allowing the diaphragm to expand and contract with both the inhale and exhale. Many runners tend to breathe in either from the mouth or the nose, not through both, and they inflate the lungs within the chest. When this occurs, the chest will expand and contract, leading to muscle tension in the back and shoulders; the ribs will also limit the expansion of the lungs, meaning less air will enter them. To counteract such problems, a breathing technique for running must be developed that allows the runner to inflate the lungs as much as possible. The diaphragm will expand when this occurs; most people notice this as the stomach expanding.
The cadence with which one breathes in and out will also help develop a good breathing technique for running. At a jogging pace, many runners prefer a 3:2 ratio, which means for three steps forward, the runner will breathe in, and then for two steps forward, he or she will breathe out. This ratio may be adjusted if the runner is running faster than a jog or in a sprint — runners often revert to a 2:1 ratio in such situations — but the advantages of slowing the breathing process may be felt immediately in the form of better muscle function, less cardiovascular stress, and a more comfortable breathing pattern.
Other runners tend to use a breathing technique for running that employs a 2:2 ratio. This means the runner will inhale for two strides and exhale for two strides. This is a good technique for running long distances or at higher speeds than a jog, and it should be combined with air intake through both the nose and the mouth.