Here is what it says about deep breathing.
'No matter what your physical troubles are, deep breathing will help to overcome them. It helps to cure cold feet by bringing more oxygen into the blood. It helps to drive away constipation by giving internal massage to the bowels. It helps to overcome torpid liver by the exercise given to that organ. It helps to cure rheumatism by securing enough oxygen to burn up some of the foreign deposits in various parts of the body. It costs nothing and has only good after-effects.'
If you have lost the knack to breathe deeply, pop along to the Breathing Club and find the time and space to rediscover it.