Lie on your stomach, head turned to one side and simply breathe, slowly and deeply, for two minutes. Pay attention to which parts of your trunk are moving. You should feel your abdomen expanding and your chest remaining relatively still. This is how we should breathe in every position. The point of this exercise is simply to reconnect your conscious mind with diaphragmatic movement so that you can begin to replicate it in all other positions.
Lie on your back and simply breathe, slowly and deeply for two to five minutes. Focus your attention on using your diaphragm, not your chest muscles, to initiate the movement. In other words make your belly go up and down. As you breathe, count. Try to make the inhale the same length as the exhale. I suggest starting with 3 seconds per inhale and then slowly increasing the length of each breath as you feel comfortable to do so. Try to breathe as slowly as you can comfortably, without making yourself short of breath.
Using your breath to stimulate your parasympathetic nervous system. Lie on your back and commence diaphragmatic breathing as described above. Gradually lengthen your exhale to make it longer than your inhale. Start with 4 seconds in, 6 seconds out. Find a pace that you’re comfortable with. Continue for 3-5 minutes
This exercise helps with diaphragm mobility. Inhale in as deeply as you can, relaxing your abdominals and feeling your diaphragm descend as far as possible. Pause. Exhale as deeply as possible, drawing in your abdominals to force as much air out of your lungs as possible. This exercise gives you a sense of the true range of movement that your diaphragm is capable of, and helps to stretch & then relax it.