Breathing from the diaphragm (the long band of muscle that lies beneath your lungs) allows for the fullest expansion possible of your ribcage. This means that more air can get into your lungs and into your bloodstream.
Singers use diaphragm breathing to be able to perform their songs with greater power and control, and learning the technique of diaphragm breathing will also improve your chances of relaxing into deep sleep.
This is a good exercise to start with, and can easily be used as a "cleansing" warm-up before doing any other form of exercise.
1. Ideally, lie on your back on a flat surface, or in bed, with your arms at your sides. If lying down isn't possible then try to find a reclining position so that the ribcage is slightly extended.
2. As you breathe in through your nose, imagine that your abdomen and chest contain an empty vessel, like a wine carafe. The opening of the carafe is your nose or mouth and the neck of the carafe is your own neck. Where the neck of the carafe opens into the basin, picture this area as your lungs and then picture the main basin of the carafe as your abdomen.
3. Breathe in and feel the air pouring into your lungs. You should slowly expand your belly first, as if the air is literally filling up your body like wine would fill the carafe. Next fill and expand your upper abdomen, then your chest, throat and mouth. You can place your hand on your upper abdomen if you need help breathing this way. Your hand should rise as you breathe in.
4. When your "vessel" is full, begin to "pour" the air out through your mouth. This time, the air will empty in the opposite direction. First from your mouth, then your throat, chest and finally your stomach. Slightly contract your stomach muscles as if you're trying to squeeze the last "drops" out.
5. Relax and breathe in again through your nose.
6. Repeat this process at least half a dozen times. Each time, try to pull in and pour out slightly more air.
If you prefer, you can imagine your stomach as a balloon - but it is important to keep the "order" in which the air fills your body. This exercise is teaching you not just to breathe deeply, but to notice and control your breathing. These skills form an important part of later meditation practices.
To continue practicing these skills, try this exercise. It may seem strange, but it will help you to expand your lung capacity and increase your sense of control over your breathing.
1. Get into a comfortable position, either lying down or sitting. Close your eyes and place the little finger of each hand on each side of your nose. Relax your other fingers against your cheeks or in a loose fist against your chin.
2. Use the left little finger to close the left nostril. Breathe in deeply through the right nostril only.
3. Now close the right nostril with the right little finger and release the left nostril. Exhale strongly through the left nostril.
4. Without moving your hands at all, breathe back in through the left nostril. Then close your left nostril and exhale through your right nostril only.
5. Repeat with each nostril as the "inhaling" nostril at least 3 times.
If you find it difficult to use both hands, try using the thumb and forefinger of one hand.
Because you are limiting the "pathways" for air to enter your lungs, you are making the lungs work harder to inhale and exhale. Over time, just as when you exercise a muscle, your lungs will get stronger and their capacity will increase, enabling you to breathe more deeply.
This exercise will get you some interesting looks if you try it in public, so just be forewarned!