As we briefly touched on above, exhalation is the key to mindful, relaxed breathing. So much so, that if you think about it, we naturally associate exhalation with serenity, security, and release of tension. There are all sorts of such cultural references to exhalation as being emotional release, as in Terry McMillan’s novel Waiting to Exhale.
One simple reason that exhalation equals relaxation is that it requires no muscular effort. You don’t have to actively push air out during exhalation— you can just passively let it out. Also, as we exhale, air pressure against the heart goes down, allowing it to more easily pump blood, and thus achieve a higher stroke volume. Thus the heart can beat fewer times per minute. Exhalation also engages our parasympathetic nervous system, which is the opposite of the fight-or-flight response. This is called the vagal response or relaxation response.
We can increase the benefits of exhalation by extending its length, somewhat counter-intuitively. We tend to think of inhalation as more important because we need air and oxygen. But we have enough air in our lungs to sustain us for several minutes, so an extended exhale phase of 8, 10, 15 or even 30 seconds barely cuts into our oxygen reserves. This concept is the essence of mindful breathing. A nice, relaxed exhale is like a massage or stress release for the lungs, an opportunity to chill out and let the accumulated stresses of the day flow out of the body. I like to start people off with an 8 second exhalation but the exact length doesn’t matter, and you certainly can do much more.
After we take the comfortable inhale with just the diapragm described above, we are ready to do the long, relaxed exhale. And we will want to exhale through the mouth, so that we can control the rate of flow of air with our lips or teeth. This is what allows us to slow the exhalation down substantially. You could use your nose, in that is possible to slowly exhale through the nose, but this requires us to concentrate a bit and eccentrically contract our breathing muscles. As an analogy, imagine that you are at the top of a pull-up position and then slowly let yourself down. This is an eccentric muscle contraction— working the muscles, not to do a pull-up (that would be a concentric muscle contraction), but to control how slowly you go down. An eccentric muscle contraction requires effort. By contrast, if you had a large rubber band under your feet to slowly let you down, you wouldn’t have to do any muscular work during the descent.
Exhaling through our lips or teeth is like having such a rubber band. You want to let the air slowly escape through pursed lips or mostly closed teeth. By doing this, we can easily control the rate of flow so that we get the 8 second exhalation that we want. So let’s try it. Take a normal, comfortable inhale, and exhale 2 3 4 5 6 7 8. Again— inhale and exhale 2 3 4 5 6 7 8. How far should you exhale? It doesn’t much matter, as long as you don’t go beyond the point of a passive exhale, that is, so don’t have to actively push the air out. Try it a few more times.
I bet you are feeling more relaxed already. And there you have it, 8 seconds of exhalation to achieve calm. I call it the 12 second meditation because it takes about 4 seconds for the rest of the breathing cycle, for a total of 12 seconds. If you were to read no further in this document, I think you already have learned something useful. Several breaths can be used for a minute long meditation, and several times more can be used for a five or ten minute meditation.
Some medical practitioners teach patients with emphysema and similar lung diseases to similarly exhale through pursued lips or closed teeth. This is because the airways of such patients are inflexible and tend to collapse easily. This is particularly problematic in the alveoli, which are essentially little balloons of thin tissue where blood circulates and exchanges oxygen and carbon dioxide with the lungs. Exhaling against a restricted flow induces back pressure. that can help the airways remain inflated during exhalation, thus better exchanging gases. While it has not been studied beyond this type of population, this effect might be beneficial for the rest of us as well.
A long exhale can also help induce something called heart rate variability (HRV), which some scientists believe is an important metric of cardiovascular health. I will not go into the details of this metric, nor surmise whether HRV induced by this type of breathing is effective at promoting cardiovascular health in the way that proponents of HRV promote, but you can look up HRV for yourself.