"Belly Breathing", or Deep Breathing is often recommended by your Therapist during Deep Tissue Massage for a reason. Deep breathes that push out your abdominal muscles will fill your lungs with air, helping your muscles to relax.
Using Deep Breathing exercises are often recommended when feeling tense, or when in pain. Practicing regularly may lead to the prevention of symptoms often associated with stress. Some examples include, high blood pressure, anxiety and head aches.