In the first part of this article I described the function of the diaphragm, and the important role it plays in maintaining organ health and good blood circulation. I now want to explain how the diaphragm’s function can be further enhanced using a special breathing technique. This method of breathing has long been known in Hatha Yoga and in some meditation techniques, and has become more widespread through its use in the Ashtanga style of yoga as taught by K.P. Jois in Mysore.
The breathing method has been described in great detail by an early European student of Jois, Andre van Lysebeth. In his book ‘Pranayama, the Energetics of Breath’, we can see rare photos of Jois checking van Lysebeth’s use of the correct musculature. This gem of a book was first published in the 1950s and is now available from Harmony Publishing.
It is worth clarifying the continuing confusion caused by Ashtanga practitioners calling the above technique ‘Uddiyana Bandha’. They are referring to the contraction of the lower abdominal muscles, which is very different from the Kriya known by the same name. In this Kriya, the abdominal muscles must remain completely relaxed.
After a full exhale, the breath is held out against a closed glottis, the ribcage expands,
and a partial vacuum is created in the thoracic cavity.
This sucks the diaphragm and the abdomen strongly upwards, creating the hollow belly characteristic of Uddiyana Bandha. In this article I am going to call the contraction of the lower abdominal muscles ‘the abdominal lock’ or ‘AL’ for short. To explain how the AL works and what it does, let’s make some coffee.
The Espresso coffee machine consists of three parts: a lower container for water, an upper container to hold the finished coffee, and a tube that connects the two containers and also holds the ground coffee. The important thing is that apart from that tube, the two containers are totally sealed from each other. We put water in the lower container, coffee in the holder and then screw the two
containers tightly together. Placed on gas flame or hot plate the water starts heating up until it produces steam. Because the steam is trapped between the water surface and the container walls, pressure builds up, just as in a pressure cooker. The increased pressure pushes on the water, which has nowhere else to go but upwards through the tube and the ground coffee and into the top container. In physics terms the lower container is at a higher pressure than the top container and fluid is sucked towards the lower pressure.
In a variation of this machine, we can produce increased pressure by pushing a plunger into the lower container, decreasing its volume and increasing the pressure. Once again, this increased pressure causes water to move towards the upper container
A very similar story holds for the human body: imagine the abdominal cavity is the lower container, and the thoracic cavity is the top container. They are separated completely by the diaphragm except for the large vena cava, which connects the two cavities. The vena cava is like the tube connecting our two espresso containers. As the diaphragm descends the volume in the abdominal cavity is decreased and the pressure rises, causing blood to be sucked towards the lower pressure thoracic cavity and into the right atrium of the heart. However, the parallels to the coffee machine are not quite accurate. Unlike the coffee machine with its rigid walls, the descending diaphragm pushes the internal organs outwards. This outward movement means that the volume in the abdominal cavity is only slightly altered. As explained in Part One, this is still enough to produce a pressure difference and assist venous return. But what would happen if we don’t let the internal organs move? By contracting our abdominal muscles (the AL), the belly no longer moves out to accommodate the diaphragm, but is held taut against the descending diaphragm. Now, this is just like our coffee machine: the diaphragm is like the plunger descending and increasing the pressure in the lower container.
By using the AL, we have greatly increased the intra-abdominal pressure,
creating increased blood flow to the heart.
And there is even more. As the diaphragm descends against the resistance caused by the AL, it also flares the rib cage, causing an expansion of the thoracic cavity. The pressure in the thorax consequently drops, further increasing the pressure difference between the abdominal and thoracic cavities and further increasing venous return.
Here we have a beautifully simple and elegant way to increase cardio-vascular activity without even having to move! For those who think that cardio-vascular exercise means lots of jumping around, think again! Part of the reason that dynamic forms of yoga are so popular is because students don’t feel they are getting enough ‘real exercise’ from traditional yoga, and so are attracted to styles which look and feel like conventional exercise. This is due to of a lack of understanding of the physiological effects of traditional Hatha yoga. There is no doubt that yogis had a deep knowledge of human physiology, even if it may have been described in terms different from ours. So before your next coffee, sit and take thirty long deep breaths using the abdominal lock, and feel how energized you become. You might not even need that coffee.