Be mindful of your breathing at all times. Maintain a deliberate, relaxed cadence of breath.
We all like to think that the mind leads the body, but in reality the mind and body are very closely intertwined. Sometimes the body can actually lead the mind. For instance, it’s been shown that smiling actually makes you happier. Similarly, controlled breathing helps keep you relaxed and conserve your energy.
Controlled breathing is especially important against a larger or more experienced opponent. Besides helping conserve your energy, controlled breathing helps keep you calm. Calmness is critical to prevent panicking when you’re seriously being challenged.