There has been a lot of research around the world especially on something called abdominal breathing, or diaphragmatic breathing
With this method, as you inhale or breathe in, your abdomen goes out, and as you exhale, your abdomen goes back in, and this is a slow, controlled type of breathing. Abdominal breathing is a core component of things like yoga, tai chi, and meditation. Even musicians incorporate this type of abdominal breathing into their daily lives. Electroencephalography (EEG) studies on this type of abdominal breathing have found that even just a few minutes of using this type of breathing alters your brainwaves in a positive way, increases your relaxation response, decreases your stress hormones, decreases your blood pressure, and increases your oxygen levels.