November 08, 2017

The Neuroscience of Yoga: Bridging the Gap Between Spirituality and Science

Yoga has become increasingly popular in the last decades and anyone who has attended a handful of yoga classes would agree to feeling an increased sense of emotional stability and mental clarity after practice. Nowadays, thanks to sophisticated brain imaging techniques, neuroscience is revealing exciting and transformative insights about the art and science of yoga. Western science is finally confirming what eastern practitioners have been reporting and documenting for over 2,000 years: that yoga and meditation can literally rewire the structure of the brain. 

What Is Yoga, Anyway?
Yoga (from Sanskrit meaning “unity”) is an ancient practice that unites the innate capacity of human beings to realize their true potential. We recognize our highest potential through the practices of the various yoga disciplines, such as yoga asana or physical postures, breathing regulation, meditation, study of teachings, devotional chanting, among others. In the West, we became familiarized with yoga asana, which only represents one aspect that the practice uses to align us with our highest potential and develop higher qualities, such as more love, compassion, humbleness, kindness, empathy, insight and service.
In the early 2000s, Richard Davidson from the University of Wisconsin jump-started the convergence of both worlds with his famous research on meditating Buddhist monks, finding mental training in form of meditation may induce short and long-term neural changes in the brain [1]. Several other researchers have followed, including Sarah Lazar, who found that brain regions associated with attention and sensory processing were thicker in people practicing meditation. The changes were observed even in novice meditators with as little as two weeks experience. This means that not only meditation professionals benefit from the practice [2]. 

Sharpening Higher Cognitive Functions
In as little as 15 years, the emerging field has witnessed almost a 10-fold increase in published research papers on the impact of yoga in human health [3]. Several papers focus on the pre-frontal cortex and the attentional engagement that yoga requires. Positive changes in the brain structure and function of areas related to awareness, decision-making, executive functions, self-regulation and attention have been observed [4], leading to an efficient regulation of emotions, social behavior, impulsivity, fears and conflicting thoughts. This area is also strongly implicated in human qualities such as empathy, consciousness, social and emotional intelligence, insight, intuition and attuned communication [5]. One of the most interesting studies in this area found that 50 year-old meditators had similar cortical thickness as 25 year-olds, suggesting that yoga might offset age-related cortical thinning [2] .

via Flickr by Amila Tennakoon

Nowadays, one of the most prevalent health threats is stress. Everybody has experienced it in one way or another. Long-term stress can have significant adverse effects on health and is a risk factor for many major illnesses, such as heart disease, stroke and depression [6]. Neurobiological studies have implicated the amygdala as a crucial area involved in our stress response. A recent study found that participants following an 8-week yoga intervention reported significantly reduced perceived stress and a reduction in the right basolateral amygdala gray matter density [7], furthering our understanding of why we feel so good during and after a yoga class. 

Breathing Into Your Memory Center
The hippocampus plays a vital role in long-term memory, learning, navigation and spatial orientation. Recent studies have found an increased hippocampal volume in elderly participants over a period of 6-months, suggesting that yoga could have the potential to alleviate age-related neurosenescence, findings of particular importance for the field of neurodegenerative diseases, such as Alzheimer’s disease [8]. Furthermore, depression is a potential risk factor for cognitive decline and dementia and recent reviews suggest that a yoga intervention might effectively reduce these symptoms [9].  
I think everyone who has taken a yoga class can relate to the unique experience that this practice brings to one’s day. Our mind can be in an absolute turmoil when getting to class, thinking about the next deadline, the shopping list, answering our boss's email, and so on, but then we feel absolute peace when lying down in savasana, the final resting posture. Yoga has been shown to restore the autonomic nervous system to a healthy balance by stimulating the parasympathetic nervous system. It reduces our heart rate and blood pressure, eases our respiration and increases heart rate variability – all signs of improved parasympathetic tone and a peaceful smiling face after class [10].

Yoga might offset age-related cortical thinning
 
A number of published papers conclude that breathing, meditation, and posture-based yoga increases overall brain health and yoga practice may be an effective treatment for a clinical and healthy aging population, in addition to being relatively easy and cost-effective to implement [11]. So now, if you have not yet experienced a yoga class, I invite you to attend one and feel for yourself all the benefits this millennial practice has to offer. After a while, yoga becomes not what we do, but rather how we do something. When we invite an ever-present awareness to all that we do, yoga becomes a way of living, rather than just a disciplined practice we commit to one hour a day.

by Stephanie Bianchi, MSc in Neuroscience / Mindful Guatemala
This article originally appeared September 2017 in CNS Volume 10, Issue 3, Spirituality in Science
 
[1] Lutz et al., Proc Natl Acad Sci, 2014
[2] Lazar et al,. Neuroreport., 2005
[3] https://www.ncbi.nlm.nih.gov/pubmed/?term=yoga
[4] Afonso et al., Front Aging Neurosci., 2017
[5] Desai, Effects of Yoga Nidra and other Meditation Techniques, In: Yoga Nidra: The Art of Transformational Sleep, 2017
[6] Tawakol et al., The Lancet, 2017
[7] Hölzel et al., Soc Cogn Affect Neurosci., 2010
[8] Hariprasad et al., Indian J Psychiatry, 2013
[9] Mathersul et al., Evid Based Complement Alternat Med., 2016
[10] Stephens, Children (Basel)., 2017
[11] Desai et al., Complement Ther Clin Pract., 2015

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