Yoga: a mind-body practice that improves the brain

Yoga is an ancient Indian mind-body practice that focuses on both movement (asanas) and breath (pranayama). Yoga was first brought to the United States around the early 1900s, but it did not gain popularity until the 1960s. Today, it is an extremely popular practice, with an estimated 9.5% of US adults using yoga as a complementary health form (NIH, NCAM). Though yoga has a rich tradition as a spiritual practice, many Americans use it today simply as a form of exercise, as yoga’s rigorous physical movements provide an excellent physical activity regimen.

Within the context of yoga, many traditional (and commercialized!) branches exist, and when you look at what is offered, you will find such forms as hatha, vinyasa, bikram, kundalini, ashtanga, acro, partner, and even naked yoga! For example, hatha yoga is a type of yoga where particular asanas (poses) are held for extended periods of time, whereas kundalini yoga incorporates many poses that involve constant movement. Though many focus on the physical aspects of yoga, yoga’s ultimate goal, as outlined by the Yoga Sūtras of Patañjali, is to attain a state of Samādhi or perfect consciousness where one is liberated from the physical self and the conscious mind is in a state of perfect balance or harmony (Satchidananda, 1978).

Though most Americans probably are not practicing yoga for the purpose of as Patañjali put forth, “to inhibit the modifications of the mind,” 21 million people currently practice yoga in the United States! As yoga has gained popularity as an American pastime, it has also gained popularity as a topic of scientific investigation, with almost 1,600 research articles being published each year (Schmalzl et al., 2015).

Like other forms of physical activity, yoga is good for the body as it improves cardiorespiratory capacity (VO2 max) and decreases resting heart rate, blood pressure, body mass index (BMI), and total serum cholesterol levels (Schmalzl et al., 2015). Yoga is also good for the mind as it decreases stress, anxiety and aggressiveness and improves mood and overall quality of life and wellbeing (Schmalzl et al., 2015). Additionally, practicing yoga can improve both short- and long-term memory as well as executive functioning such as problem solving, attention and cognitive flexibility (Schmalzl et al., 2015). This work on the effects of yoga on cognitive functioning points to the ability of yoga to improve an area of our brain called the prefrontal cortex, known to be involved in decision making and the planning of complex behaviors.

Based on this information, one recent scientific review set out to examine the specific neural changes that occur as a result of a long-term yoga practice. In one set of studies, electroencephalography (EEG) was used to study the effects of yoga on brain wave activity. These brain waves reflect the overall electrical activity of the brain and are composed of different oscillations that support specific behaviors and thought processes. One predominant finding was that yoga specifically increased the so-called alpha waves (Desai et al., 2015). Alpha waves occur when the neurons in our brain fire together at a frequency of between 8 to 13 times per second. Alpha waves are typically observed when an individual is awake but restful or in state of deep relaxation. Therefore, this means that by practicing yoga we can significantly change our brain’s electrical activity, shifting it towards a more calm, meditative state. Additionally, several studies examined the blood flow or energy consumption of specific brain regions using functional magnetic resonance imaging (fMRI). By using this technique, researchers found that a long-term yoga practice increased blood flow to the frontal lobes and decreased blood flow to the amygdala (Desai et al., 2015). In a general sense, the frontal lobes provide us with our cognitive abilities, and this part of our brain becomes active when we are problem solving. Additionally, the amygdala allows us to regulate our emotions, becoming more active in stressful, agitated, or heightened states of emotion. Therefore, this work reveals that yoga is able to stimulate the “thinking” part of our brains and tone down or help us regulate the “emotional” part of our brains.

A very recent study examined whether yoga is neuroprotective; that is, whether practicing yoga can help to stave off age-related brain matter loss (Villemure et al., 2015). Fourteen experienced yoga practitioners with a range of 6-16 years of yoga experience and practicing 4 to 18 hours a week were compared to 14 physically active controls, matched on sex, age, BMI, education, handedness, and exercise level outside of yoga. Grey matter volume (GMV), a measure of the cell bodies of neurons, was examined across several brain regions. In controls, whole brain GMV negatively correlated with age, whereas in the yoga practitioners, no such association was seen. Further, both the number of years of yoga practice as well as the current number of hours of weekly yoga practice was positively associated with GMV in several regions of the brain, including the cortex and hippocampus. This study shows that yoga may protect the brain from age-related loss in brain tissue and that the more yoga you practice, the better!

Of course, future research is needed to understand which aspects of yoga contribute most to improvements in brain function and growth. However, research has certainly revealed that yoga is an effective way to improve mood, increase cognition, enhance brain functioning, and stave off age-related loss of brain matter.

References:

Desai, R., Tailor, A., & Bhatt, T. (2015). Effects of yoga on brain waves and structural activation: A review. Complementary therapies in clinical practice, 21(2), 112-118.

National Institutes of Health, National Center for Complementary and Alternative Medicine (2015). Use of Complementary Health Approaches in the U.S.: National Health Interview Survey. Taken from: https://nccih.nih.gov/research/statistics/NHIS/2012/mind-body/yoga.

Satchidananda, Sri Swami (1978). The Yoga Sutras of Patanjali. Integral Yoga Publications: Buckingham, VA.

Schmalzl, L., Powers, C., & Blom, E. H. (2015). Neurophysiological and neurocognitive mechanisms underlying the effects of yoga-based practices: towards a comprehensive theoretical framework. Frontiers in human neuroscience, 9.

Villemure, C., Čeko, M., Cotton, V. A., & Bushnell, M. C. (2015). Neuroprotective effects of yoga practice: age-, experience-, and frequency-dependent plasticity. Frontiers in Human Neuroscience, 9.