BKS Iyengar wasn’t the last giant to throw light on yoga. Western science does it almost every day, and yoga reflects light back in the other direction. In this two-way outburst of light, we can see new landmarks in the territories of science and yoga. Observing them has transformed my yoga practice lately and enhanced my understanding of science.

One study done here in Boston compares the effects of walking and yoga on the chemical balance in the brain. Using technology that makes Star Wars seem pre-historic, researchers demonstrated that the amino acid GABA is more elevated after practicing yoga than after going for a walk.  Same calories burned; different GABA levels.

I feel great after a long walk and I feel great after a yoga practice. But they’re two different kinds of great – there’s a qualitative difference which I’d be hard pressed to describe.  Who would have thought that a chemical marker could articulate this difference better than words?

Equally fascinating is that this same chemical has pharmaceutical uses: it moderates the symptoms of epilepsy and of disorders of mood and anxiety.  So…the difference I experience between the wonderfulness of walking and of yoga just might be a shadow of this healthful effect of GABA.  Besides diminishing suffering for people with these severe disorders, more GABA may actually be good for my own nervous system.

Not surprisingly, yoga came out on top.  I was looking for studies of yoga benefits, after all.  But more interesting than who won the contest, was one of the scoreboards.  The quiver of arrows in this diagram represents the body’s defensive reaction to stress.  The asterisks show where yoga has a documented effect.

How do studies like these slowly transform my yoga practice?  By helping me to remember that the physical benefits of yoga run much deeper than my bones and muscles.  They’re grounded in my chemistry, in the way my molecules interact.  When my hips grind in sukhasana or I tumble out of a handstand for the umpteenth time, I’ll remember that my cells (and indeed my Self)  may imbibe the benefits of yoga all the same.

As for my understanding of science, these studies remind me of something the ancients surely knew all along.  Using the searchlights of their own experience, they explored dark territory that clinicians are only now broaching.  The ancient Indians were there first and they observed many of the same phenomena, albeit through different lenses.  These studies remind me that the human body and mind –the only important tool yogis have ever used, and which we all possess – may be the most sensitive instruments of measurement on the planet.