One of the most important and often overlooked components of exercise is breathing. Not only does breathing allow oxygen to be circulated through the bloodstream, but is also effective for moving fluid through a gentle pumping action of the abdominal muscles. The fluid is pumped through the central lymphatic vessel in the chest cavity, stimulating the flow of the lymph.
When you breathe in, using your abdominal muscles, the pressure in the chest cavity changes, because the belly breath moves your diaphram.
When you exhale, the pressure changes once again. This back and forth alternation in the pressure acts like a pump on the large lymphatic pump that runs up through the chest cavity and drains into the venous system of the neck.
Sit in an upright postion. Take a deep breath through your nose and exhale through your mouth, flattening your belly and squeezing out every bit of air.
Emptying the lungs completely and removing all the stale air from the bottom of your lungs automatically stimulates a diaphragmatic breath. Breath in through the nose and notice how your belly expands. Repeat the sequence again. Let the air out through the mouth, making sure your belly flattens. Try another one or two breaths this way. If you feel light headed try to slow down your inhalation and pause before breathing in again.
It is not neccesary to breathe with a giant breath- just one thats goes to the bottom of your lungs while your chest remains still. Imagine a ballon in your stomach that inflates when you inhale and deflates when you exhale.