We take upwards of 54,000 breaths per day, yet we rarely think about how we breath. We just do it. Having good respiratory patterns sets you up for success in mental, emotional, and physical health.
Before we start you need to know a little anatomy.
The Thoracic Diaphragm
The diaphragm is the primary muscle of respiration. It is a dome shaped muscle that separates the thoracic cavity from the abdominal cavity. It attaches from the lower ribs to the spine.
It has three main function, the respiration function, a stabilization function, and a sphincter function.
Respiration and the Diaphragm
When the diaphragm contracts the central tendon descends towards the abdominal cavity, increasing the volume in the thoracic cavity, which in turn decreases the pressure in the thoracic cavity (where your lungs are) and brings in air. This is the respiration function of the diaphragm.
At the same time the diaphragm is descending it is creating higher pressure in the abdominal cavity, known as intra-abdominal pressure (IAP). IAP is the base of stability for the lumbar spine.
Intra-Abdominal Pressure
The reason we need IAP is due to the fact there are no muscles that directly attach to the lumbar spine that create flexion. We need something to offset the large erector spinae muscle group, these large muscles produce extension of the spine. Many of us use these muscles to stabilize the lumbar spine by hyperextending and locking everything down. If this contraction is not offset by IAP it will create high compression forces on the discs of the lumbar spine.
Intervertebral Disc
The intervertebral discs do not like uneven compression. If you think of each disc as a jelly filled donut, there is a gel like substance inside called the nucleus pulposus, and a tough fibrous outer ring called the annulus fibrosis. With uneven compressive forces, this jelly like substances can eventually make its way through the annulus causing disc herniations. The nucleus pulposus is there to evenly distribute compressive forces at that level of the spine. However, if that level is being overloaded due to poor stability it will eventually stop doing it's job.
Stabilizing the Lumbar Spine
This is where intra-abdominal pressure comes in handy. In the image to the left the blue arrows are IAP, they give a pushing out force against the lumbar spine. In red you have the connective tissue on the posterior or back side, the main contributor is the thoracolumbar fascia. The forces of the IAP and the thoracolumbar fascia create a sandwich effect of the lumbar spine, which stabilizes the spine from excess movement. When the spine is stable, it can distribute forces evenly throughout the spine and body, which will take pressure off of the passive structures like the discs and ligaments. This reduces the chances of disc injuries in the low back.
The often forgot sphincter function of the diaphragm
Lastly, the diaphragm has a sphincter function. There are three main openings that are in the diaphragm, they are for the inferior vena cava, the esophagus, and the aorta. While blood needs to get from your heart to your toes and back, which is what the aorta and inferior vena cava do, we do not want food and stomach acid going back up into the esophagus, also known as gastroesophageal reflux. Having good control of the diaphragm will help seal off the lower esophagus from the stomach decreasing the chances of reflux.
Learning to breath with ideal patterns not only helps bring air into the body, it is the first step in stabilization of the trunk along with increasing digestive health.
Here is a quick video to start learning how to use your diaphragm with proper patterns.