During the first few cycles of Vinyasa practice, focus on your breath. Engaging the respiratory muscles moves air in and out of the lungs, oxygenating the blood and removing carbon dioxide. The alveoli in the lungs are microscopic sac-like structures that have a thin membrane separating air from the blood in the capillaries. This is where gas exchange takes place. These alveoli are elastic in nature, expanding like a balloon on inhalation and then passively recoiling back down to size on exhalation. Oxygenated blood is transported by the circulatory system from the lungs to the tissues of the body, where it is consumed for metabolism. Carbon dioxide is produced in the tissues as a by-product of metabolism and is transported to the lungs for release into the air.
The main muscle of respiration is the diaphragm. It is a thin, dome-shaped muscle that separates the chest cavity from the abdomen. Contracting the diaphragm during inhalation causes the dome to flatten out. This increases the volume of the chest cavity and draws air into the lungs via the trachea and bronchi. The diaphragm functions unconsciously, so that it contracts without you thinking about it. You can also contract it consciously, which is what happens if you intentionally breathe faster or more deeply. Exhalation is a passive process that occurs as a result of the elastic recoil of the chest wall and the sac-like alveoli. As you exhale, the diaphragm relaxes back into its dome shape, decreasing the volume of the chest.
FIGURE 1 Make exhalation a more active process when practicing Vinyasa Flow. Do this by gently engaging the abdominal muscles, activating the rectus and transversus abdominis. Slightly squeeze the chest as well to contract the muscles that connect one rib to another: the internal intercostals.
Activating the transversus abdominis increases intra-abdominal pressure. This increased pressure causes the abdominal organs to be lifted up against the diaphragm, aiding to empty the lungs. Contracting the internal intercostals brings the ribs closer together, thus decreasing the volume of the thorax (the chest) during exhalation.
Bear in mind that the lungs are never completely empty. There is always what is called the “residual volume” that remains in the non-compressible elements of the respiratory system—the bronchi and trachea. Contracting the abdominal and intercostal muscles expels some of the air remaining in the elastic, sac-like structures of the lungs where gas exchange takes place. Make exhalation an active process during Vinyasa to decrease this residual volume. This aids to remove more of the carbon dioxide that is produced during metabolism.
FIGURE 2 Inhalation is, for the most part, driven by the diaphragm. The phrenic nerve controls this muscle, which functions both consciously and unconsciously. The diaphragm will do its work automatically, but you can direct the frequency and depth of each inhalation.
The brain can recruit the accessory muscles of breathing to increase ventilation when the body needs more oxygen. Watch a sprinter at the end of a race, and you will see that they are engaging muscles in the neck, back, chest, and abdomen to increase lung volume. This happens automatically when more oxygen is needed and more carbon dioxide must be expelled.
You can augment the depth of inhalation during Vinyasa by training yourself to contract certain of the accessory muscles of breathing. I primarily use a combination of the rhomboids, pectoralis minor, and serratus anterior. Begin by engaging the rhomboids to draw the shoulder blades toward the midline. This opens the chest forward. Fix the shoulder blades in place, and then expand the chest upward and outward by activating the pectoralis minor and serratus anterior muscles. A cue for isolating the pectoralis minor is to attempt to roll the shoulders forward; at the same time, activate the rhomboids to prevent the shoulders from moving. As a result, the contractile force of the pectoralis minor is transmitted to its origin on the ribcage, lifting it. To engage the serratus anterior, imagine pushing outwards against a doorway with the hands. Note how this expands the chest.
The serratus anterior and pectoralis minor muscles can be difficult to access at first. Therefore, I recommend simply “going through the motions” at the beginning of your practice a few times—like making a rough sketch. Then leave it. For the rest of your practice simply breathe deeply. In the time between sessions, your unconscious brain will honor your effort and form circuitry to more efficiently activate the accessory muscles of breathing at your command. Don’t try too hard and don’t give up.
FIGURE 3 Just as squeezing the abdomen exerts an upwardly directed pressure on the diaphragm, so does the rhythmic contraction of the diaphragm flatten to compress and massage the abdominal organs. Then, as the diaphragm relaxes and returns to its dome shape, the abdominal organs are drawn upward. This creates a “pumping” type of action on the blood-filled sinusoids of the liver and spleen, improving circulation through these organs and detoxifying the blood. The lymphatics that surround the intestines are massaged, stimulating the immune system. The rhythmic pumping action of yogic breathing on the stomach and intestines also improves digestion and elimination.
Gently activating the abdominal muscles during Vinyasa tones them, while at the same time raising the intra-abdominal pressure. This increased pressure creates a resistance for the diaphragm to contract against as it flattens, exercising and strengthening it.
FIGURE 4 The glottis surrounds and includes the opening between the pharynx and trachea (windpipe). You can decrease the size of this opening by contracting the muscles of the glottis. Decreasing the size of this aperture creates turbulent airflow, producing the characteristic sound of ujjayi breathing. This sound resonates through the chest, which functions like a speaker box. The rhythmic sound of ujjayi (sometimes called “ocean breath”) is reminiscent of waves on the beach.
Air is warmed as it passes over the blood-rich mucosa that lines the nasal sinuses and pharynx. Creating turbulence within the glottis increases the time that the air is in contact with this mucosal lining, warming it further. This forms part of the basis for pranayama.
Finally, there is a biomechanical benefit to working with ujjayi breathing in yoga. Narrowing the opening of the glottis creates a resistance to airflow into the lungs. Thus the diaphragm has to work a little bit harder to draw the air in, giving this muscle a light workout. Strengthening the diaphragm during yogic breathing has benefits that carry over into your daily life, as breathing feels lighter and easier.
