I was told it wasn't necessary for upper extremity patients. Yet with experience and time I have come to realize that unless I actively teach my patients deep breathing, all of them, even those who don't have lymphedema but are frightened that they might develop lymphedema, I wasn't doing my part as a therapist. So now all my patients get more instruction in deep breathing than any other component of self care. The major problem with poor breathing is poor oxygenation. If there is poor oxygenation there is no energy.
Poor oxygenation causes listlissness and depresses mood.
Furthermore poorly oxygenated systems are stressed. The body doesn't care where the stress comes from, but it always responds in the same way, by tightening muscles, including the diaphragm. The neat thing is this stress response can be changed both mentally and physically. Or, change your body - practice deep breathing, exercise and stretching and reduce your stress. The lymphatic system needs a relaxed body to operate properly.