Being stressed can cause you to tense up and breathe shallowly from your chest, rather than deeply from your belly. By learning to breathe in a deep and relaxed way, you can help break the stress cycle. Belly breathing, unlike chest breathing, involves slow, deep breaths from the belly. It does not engage your neck and shoulder muscles. They stay loose to help you stay relaxed.
When you practice belly breathing, bring attention to your abdomen and take controlled, deep breaths. Let your belly fill and expand with each inhale, and relax and flatten with each exhale.