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Yoga May Increase Gray Matter in the Brain

Costa Rica Yoga

(This weeks Science post is coming to you a little bit late and from beautiful Costa Rica. Thanks Em for being my model for this shot)

Increasingly, scientists are conducting studies looking at how practices such as yoga and meditation effect the brain. For centuries in the east there has been a tradition of rigorous practice and acceptance of yogic techniques as being beneficial for people in innumerable ways.  For better and worse the west is not often convinced by anecdote or public consensus alone. We love to attempt to create a controlled environment and then adjust one variable and see what results. This is the basis for our scientific method. Culturally we may seem slow to adopt certain practices that others have trusted for centuries, but in the process we usually add a deeper understanding of the mechanisms behind the results that others experience.

paper published recently in the journal Evidence-Based Complementary and Alternative Medicine provides details of a study that looked at how the brains of practitioners of Hatha Yoga Meditation compare to those with no experience. They measured this difference by looking at the density of gray matter. Gray matter is a type of brain tissue. For our purposes you can think of regions of gray matter as processing centers. Our brain has many of these centers. The creators of this study hypothesized that practitioners of YMP would have a greater density of gray matter in a number of regions including the prefrontal cortex and the hippocampus. They also predicted significantly less self-reported cognitive failures in those who practice YMP.

Previous studies have shown significant correlations between a decrease in gray matter density in specific regions and smoking, aging and adolescent childhood abuse. The consensus seems to be that gray matter increase is beneficial and losing gray matter is detrimental. It is then a decent hypothesis that something which helps to build gray is beneficial for our health and well being.

Hatha yoga techniques, including physical postures (asanas), breathing exercises (pranayama), and meditation, involve the practice of mindfulness. This study refers to this as Yoga Meditation Practice (YMP). The 7 participants who were adept at YMP all reported having a consistent daily practice of 45 minutes or more for the past 5 years or longer. The control group consisted of 7 people who reported no current or past dedicated meditation or yoga practice.

From the authors, “prior studies have identified differences in gray matter volume (GMV) between long-term mindfulness practitioners and controls, no studies to date have reported on whether yoga meditation is associated with GMV differences. The present study investigated GMV differences between yoga meditation practitioners (YMP) and a matched control group (CG). The YMP group exhibited greater GM volume in frontal, limbic, temporal, occipital, and cerebellar regions.”

All participants were scanned using an MRI. As you are likely familiar, an MRI (Magnetic Resonance Image) is a machine with giant magnets that is used to generate an image of internal organs, in this instance, the brain. It can be used to not only get a general image of internal organs, but also to determine the density of a particular area. This study is one of a growing number that look at the effects of mindfulness. Here “the state of mindfulness is characterized by a nonjudgmental and metacognitive monitoring of momentary thoughts, emotions, action urges, perceptions, and bodily sensations.” When meditators speak of equanimity, the state of composure, calm and level-headedness they are speaking of the effect of remaining mindful. We can learn to cultivate equanimity using mindfulness practices. Mindfulness is a focus practice involving “repeated placement of attention onto an object while alternately acknowledging and letting go of distracting thoughts and emotions.” To readers of this blog this should sound familiar. I have talked about how to focus before and the state of mind that this produces is also a good example of FLOW, of “being in the zone.

So what were the results of this study? “YMP exhibited volumetrically larger brain structures and fewer lapses in executive function in daily life. Structural differences were particularly evident in brain regions subserving higher-order control of cognitive and motor responses…. study findings suggest that the practice of hatha yoga is associated with enhanced cognitive function coupled with enlargement of brain structures held to instantiate executive control.” In plain english, yoga tones not only your body, but your brain as well.