The benefits of deep breathing are literally endless. With so many people living a high stress 100 mph lifestyle nobody ever just stops to breathe. Most of us (including me) shallow breathe which means you only breathe in the very shallow section of your lungs, now your lungs are pretty damn big so to neglect them so much is really under working them. No wonder we get so out of breath as soon as we do some intense training.
Try these two tricks first:
1: Sit up straight, now breathe in as deep as you possibly can do and hold your breath for a couple seconds... Do you feel slightly light headed? That is because of the huge oxygen deprivation we give brains everyday.
2: Sit up straight, now breathe in as deep as possible (your rib cage should rise up), without letting your rib cage or diaphragm lower down I want you to blow out as much as possible. You should really feel your abs tighten and contract on the exhale, this is how you should breathe when you are training. Breathe out on the powerful part of the exercise eg. The upwards phase of the squat.
When you are lay in bed practice this relaxation technique, it as simple as breathe in and out as deep as possible. Really focus on filling your lungs up and then emptying them, it is great practice for your cardio and respiratory system.
By this point I guarantee you will be relaxed, have no thoughts and you will drift off into a quicker deep sleep.