What is diaphragmatic breathing?
Most people, when relaxed, already breathe this way naturally. However, when it’s time to speak, some people become tense, and therefore use more shallow, “chest” or “clavicular” breathing (breathing moving the collar bone, or “clavicle”). This can become a habit, so you don’t even realize you are tense when this is happening. It can also lead to vocal cord tension and muscle tension around the vocal cords, and gives your voice a quieter, less powerful sound.
Diaphragmatic breathing is deeper, more relaxed breathing, which gives your voice more support, and allows you to speak more loudly and sound more powerful with less effort and no strain on the vocal cords or surrounding muscles.
What is happening during diaphragmatic breathing?
The diaphragm is a muscle that runs underneath your lungs across your body. When your body needs to breathe, it is because there is lower pressure in the lungs than in the outside air, so the nervous system sends a signal for the diaphragm to contract. As the diaphragm lowers, your lungs are pulled down, and become enlarged, and the air rushes in to equalize the pressure. As you breathe in, you will feel your lower abdomen expanding in 3 dimensions, like a balloon, not just movement toward and away from the spine, but also up and down, and to the sides. This is because your lungs are in the centre of the body, and expand in all directions. It may feel like your body is expanding outward from the hip area. Your ribs may also separate outwards and your chest may rise. Just because you are using the diaphragm, it doesn’t mean your chest will be still! It just means the air is going lower down into the body as well. Once you feel full of air, you won’t need to breathe in any more. There will be a brief moment of stillness that may feel like the apex of a swing, when the pressure in your lungs is higher than the air outside of the body. Then your diaphragm relaxes, and your lungs begin to release the air back out, and your lungs and ribs move back elastically to their original shape.
How does diaphragmatic breathing impact upon the voice?
Diaphragmatic breathing results in a more powerful voice because using the back and bottom of the lungs allows for more air in the body, and therefore more air moving out through the vocal cords when your speak. When you use diaphragmatic breathing, there is enough air to blow smoothly through the vocal cords, without overusing any muscles to push the air out. There is enough air and it is moving quickly enough that there are no gaps when the muscles need to tighten to keep the air moving. I sometimes use the analogy of a tube of toothpaste; if the tube is very full, just a little effort to move the toothpaste will result in a lot of toothpaste coming out of the tube. If the tube is nearly empty, you really need to squeeze to get enough toothpaste out. It’s the same thing with air: if there is enough air, the voice will be able to come out smoothly, without squeezing the muscles, but if there is not enough air because there is only chest breathing, your muscles will tense to try to force more air out, and the result sounds strained and weak.
How does clavicular breathing impact upon the voice?
If you speak infrequently throughout your day, there may not be an impact on your voice, but there still may be muscle tension, and your voice may be quiet or even hard to hear. If you use your voice often, however, the muscles around your vocal cords, and in the neck and shoulders, and even rib cage, may become tight and tense. Your vocal cords themselves may work harder to squeeze shut, and this can result in bumps on the vocal cords, hoarseness, and throat pain when speaking. Eventually, overuse of clavicular breathing, along with vocal misbehaviors (such as yelling, using falsetto, etc.), may even result in losing your voice for a short or long period of time.
Sources: Borden, Gloria J., Harris, Katherine S., and Raphael, Lawrence J. Speech
Science Primer: Physiology, Acoustics, and Perception of Speech. 4thed.
Baltimore, MD: Lippincott Williams & Wilkins, 2003.