Over its four thousand year history yoga has accumulated a heavy burden of radical claims for its powers to tackle stress and foster mental and physical well-being. Inspired by these claims, and often by their own positive experiences in the yoga studio, scientists are now starting to take yoga seriously.
Some of yoga’s health-giving boasts reside in with the mystical hippy-fringe. Others are thinly disguised strategies to extract money from the rich and needy. Nevertheless, a view is emerging, still fragmentary, of a discipline that uniquely blends physical activity and mindful meditation to influence some aspects of our body’s inner physiology.
Rather than simply inducing an unquantifiable sense of ‘wellness’, recent studies have shown that yoga can create remarkably precise changes in our bodily states. Chris Streeter and colleagues at Boston University have shown that, compared to walking for the same period, 12weeks of regular yoga, caused a significant increase in levels of Gamma aminobutyric acid, or GABA as it is known, in a part of the brain called the thalamus. GABA is one of the brain’s most potent neurotransmitters and a powerful inhibitor of neuronal activity. Furthermore, the amount of GABA released was tightly correlated to reports of improved mood and reduced anxiety by the yoga-practicing subjects.
So how does hanging out in downward dog cause an increase in GABA and what does that have to do with our response to stress? The precise chain of cause and effect is still not fully understood, but it seems to have a lot to do with our breathing.
We all know what stress feels like. Sitting in line for a job interview or giving an important presentation, our heart rate goes up, our palms prick with sweat, our stomachs churn and our breathing becomes faster and shallower. These deep bodily functions are all controlled by the autonomic nervous system and, for the most part, these responses kick in whether our conscious minds want them to or not.
Breathing is a little different. We can decide how rapidly to breathe. This means when we take the proverbial deep breath and step into the interview or onto the stage, our bodies take heed. This information that says we are breathing normally is ferried, by the autonomic nervous system, back to the brain where an all-clear signal is issued and we continue to function normally.
Yoga takes this observation and runs with it. It teaches us awareness of breath and how to control it. Essentially we learn to trick our bodies into a fast-breathing ‘fight or flight’ state, but we also learn to navigate safely back to a relaxed and slow-breathing ‘rest and digest’ mode. Importantly, given the findings of the Boston group, it is again the thalamus that receives this information from the autonomic nervous system and relays it to the thinking and emotional centres at the front of the brain.
Of course yoga isn’t just about breathing. Independently two other neuroscientists have focused their attention on the effects of meditation, another crucial part of the yoga discipline. Both scientists used brain scans to search for physical changes in the brain’s structure induced by meditation. Michael Posner and colleagues in Oregon showed that just 11 hours of meditation increased the size and integrity of a major neural pathway in a part of the brain called the anterior cingulate cortex. Meanwhile at Harvard, using a slightly different technique, Sara Lazar observed significant changes in the density of brain cells in several regions including the amygdala and the hippocampus. These structures are all intimately involved in emotional regulation, self-awareness, learning, memory and the response to stress. The studies show that the physical structure of the brain is remarkably responsive to the effects of meditation and bolster claims that the positive effects of meditation and yoga are very real and long-lasting.
Taken together, these findings support what those of us lucky enough to have practiced yoga with a skilled teacher know intuitively: yoga is strong medicine. More research is needed to firm up preliminary findings, and more emphasis must be placed on ensuring yoga teachers are properly trained to avoid unwanted side-effects such as serious neck injuries. Nevertheless, doctors and health policy-makers should take heed. Many pharmacological fixes for stress disorders are either antacid-like in their timid treatment of symptoms, or crude sledge-hammers that can cause extensive collateral damage.
Through breathing, meditation and physical practices, yoga provides tools that empower people to deconstruct unhealthy and damaging stress responses and re-build a more balanced and healthy inner state. It is even quite fun.
Go forth and do yoga. (But even if you can’t, or don’t want to, please don’t forget to breathe.)
Dr Ben Martynoga is a neuroscientist at the National Institute of Medical Research.
Veena Ugargol will be leading our upcoming 8-week course on Yoga Therapy For The Mind from Sunday 27th January 2013 to Sunday 17th March 2013. For more details and to book, click here.
We also run an 8-week Mindfulness course led by author of The Mindful Manifesto, Ed Halliwell, beginning on Friday 25th Jan 2013 until Friday 15th Mar 2013. For more information and to book, click here.