by Nina
When I first starting taking yoga, I was confused about why my teachers were always rushing put to a folded blanket under my head when I was lying on my back. Something about the position of my head when I was lying on the floor was driving them crazy, but what was it? And why was it such a problem?
Later I learned that they were adding this support because, when my head was flat on the floor, due to tightness in my shoulders, my neck was arching up and back and my chin was tipping away from my chest. Putting the folded blanket under my head allowed me lie with my chin pointing toward my chest like this:
This was considered to be the proper--and healthy—position for the head in supine poses. So I went along with it. But secretly I continued to wonder why. In case you have already noticed, I'm like that—always wanting to know the whys as well as the hows, always wanting to dig a bit deeper. Which is probably why I ended up as a yoga blogger, but I digress.
Anyway, it was only when I learned about baroreceptors that I found a satisfactory explanation. As I mentioned yesterday (see
Why You Should Love Your Baroreceptors), when your neck is slightly flexed (the position when your chin is pointing toward your chest), the position puts some pressure on the baroreceptors in your carotid arteries. And this pressure can cause the same response as an inverted pose does on your nervous system—switching you from fight or flight to the relaxation response. The opposite neck position with your neck in extension (a backbend position with your chin tipping away from your chest) can have the opposite effective, stimulating your nervous system.
Of course, this understanding of the role of baroreceptors in yoga poses is very recent. In fact, the understanding of the role in regulating blood pressure in general is pretty recent as well. So the yoga teachers, like B.K.S. Iyengar, who developed restorative yoga discovered the best position for the head through personal observation, not science. (That says a lot about personal observation, doesn't it?) Interestingly, the head position Jalandara Bandha, with neck flexed and chin pointing down toward the chest, used in seated poses for pranayama, which is much older than restorative yoga, was probably adopted for the same reasons. Yoga practitioners noticed that head position enhanced the quieting effect of the practice.
I thought I'd tell you all this not just because you might not have made this connection on your own, but because I also realized there might be some people out there who don't have teachers running to put a folded blanket under their heads every time they lie in a supine restorative pose. So that's both the how and why for you. The how is that when you lie on your back, if your chin does not easily point down toward your chest, always add some support under your head. The why is that having your chin pointing down toward your chest will enhance your relaxation due to slight pressure on your baroreceptors.
Long live head support!