Effect of Yoga on neuroplasticity of Brain

Scientific Perspective

Dear Readers,

How do you feel after doing yoga…can you describe it ?

For me, I feel calm but energised, relaxed yet strong and refreshed throughout the day. This feeling creates a virtuous cycle of practicing yoga daily. I get a somewhat similar feedback from my online Yoga class students, adults and kids alike. If you are interested to join Dr. Yoga’s free online classes, drop me a email-yogawithdrshilpi@gmail.com.

The feeling of euphoria can also be experienced after exercise.

1) This happens because exercise helps to stimulate parts of brain to release neurotransmitters, like endorphins and also stimulates the release of dopamine, norepinephrine, and serotonin. Besides, increase in levels of glutamate and gamma-aminobutyric acid, or GABA is noticed after intense exercise¹. These neurotransmitters drive communications between the brain cells that regulate physical and emotional health. These chemicals boost your mood, cognitive function and overall sense of well-being.

2) Regular exercise also helps to balance stress hormone levels in the body, such as adrenaline - flight and fight hormone. Moreover, scientific evidences support that sustained exercise promotes the ability to acquire new motor skills².

3) Besides impacting brain health, exercise also has potential positive benefit on cardiovascular health, boosts immune system, strengthen muscles and also aids in weight loss.

At this point, you must be wondering that if exercise is so beneficial, WHY do Yoga?

Here, I want to emphasise that to achieve above-mentioned benefits one should indulge in aerobic exercises for least 150 mins of moderate intensity and 75 mins of vigorous intensity in a week. Maximal benefits can be achieved if the duration is increased to 300 mins in a week. Moderate intensity is when during exercise heart rate (HR) is 64% and 76% of maximum heart rate (MHR) and vigorous or high intensity when HR is 77% and 93% of MHR level³. You can calculate your MHR by subtracting your age from 220. Yoga on the under hand is based on the principle of “Sthiram Sukham Asanam” which simply means a steady and comfortable state’.

Yoga is a multimodal discipline involving physical postures (asanas), breathing exercises (pranayama), and meditation (dhyana and samadhi). It is an ancient (5,000 BC – 3,500 BC) practice to connect the mind and body with higher consciousness. It involves the practice of mindfulness, which is characterised as the openness to adopt a non-judgemental awareness of present and metacognitive monitoring of thoughts, emotions, perceptions. The physical aspect of yoga, i.e. asanas or postures have a lot of similarities with exercise- it is excellent at building strength, flexibility, cardiovascular health, boost immunity, improves brain function and also motor skills. 

Besides, other two limbs of yoga, pranayama and meditation works brilliantly to improve and normalise distressed breathing patterns, which is key to shifting an individual from the taxing ‘fight or flight’ mode of the sympathetic nervous system and enhancing the ‘rest and digest’ mode of the parasympathetic nervous system to achieve homeostasis. In summary, yoga benefits physical and mental health via down-regulation of the hypothalamic-pituitary-adrenal axis and the sympathetic nervous system. Furthermore, general physical differences between yoga and exercise are outlined below:

• Yoga is relaxing, it stimulates parasympathetic nervous system. Exercise is tiring as it stimulates sympathetic nervous system

• Subcortical regions of brain dominate in yoga whereas cortical regions dominate in exercise

• Yoga is anabolic (conserves energy) whereas exercise is catabolic (breaking down the energy)

• Yoga is energising whereas exercise is fatiguing

• Awareness is internal in yoga, which helps in self-awareness. In exercise, awareness is external and there is generally no aspect of self awareness.

Here my aim is to implicit the universal aspect of yoga, i.e. yoga is for everyone and every-body, no prior skills needed. Yoga is like a package deal. A scientific review after analysing several studies have also concluded that, yoga may be as effective as or better than exercise at improving a variety of health-related outcome measures⁴. Disclaimer: I also do love exercises!

Let’s now put on our scientific explorer lens and look into the impact of yoga on our body. To make this exploration journey fun and easy, I’ve divided this ‘scientific perspective series’ into multiple short-form reads. In each article, I’ll be covering one aspect of our body. Each article will comprehensively discuss associated scientific evidences and will discuss both the pros and cons of the published studies.

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In this article (1/n), we will understand the Science behind the effect of Yoga on Neuroanatomical Plasticity (structural and anatomical changes) in Brain.

Yogic traditions tell us that disciplined practice of yoga and meditation over time helps yogis to develop greater mindful awareness together with lasting psychological & biological benefits. Now with the aid of modern methods to investigate the neurobiology of the human brain using MRI, PET, SPECT, EEG and blood biomarker analysis, scientists and physicians can understand how yoga changes brain. 

Below is the summary of some of the international peer-reviewed neuro-imaging studies of yoga. For most studies, test group comprised of yogic practitioners with >45-minutes per day, three-four times per week, >three years practice of asanas and engaging in mindfulness meditation on each day, >four years practice and control group was meditation and yoga-naïve participants, however matched for age, sex, body mass index, education and exercise level other than yoga postures. Their findings demonstrated that in comparison to control group, yogic practitioners demonstrated:

1. Significantly greater gray matter volume in the cerebellum, increased in right cingulate, left dorsal mPFC and insula were positively correlated with better cognitive function⁵

2. Higher gray matter density was found in the medial frontal gyrus, superior frontal gyrus, precentral gyrus, (para)hippocampal gyrus, insula, superior temporal gyrus, occipital gyrus, and cerebellum⁶ 

3. The reported structural changes in the insula uniquely correlated with pain tolerance in yoga experts

4. Compared to the controls, the yoga group showed increased gray matter density in the inferior frontal gyrus (pars orbitalis), correlated with general well-being after yoga training

5. Cortical thickness increased in right insula, right cingulate cortex 

6. Significantly larger prefrontal cortical regions (including the middle and orbital frontal gyri) hence improving the cognitive performance of the individual⁷ ⁸

7. Increased hippocampal gray matter volume and gray matter density⁹ was positively associated with improved memory abilities¹⁰

8. Yogi group also reported a lower mean score of cognitive failures as assessed by Cognitive Failures Questionnaire (CFQ)

9. Decreases in density and volume were observed in the amygdala which significantly correlated with decrease in perceived stress scores.

The changes in gray matter volume was positively correlated with the duration of yoga practice. Studies indicated that yoga practice may be associated with the promotion of neuroplastic changes in executive brain systems, which may confer therapeutic benefits that accrue with repeated practice.

In a follow-up study in the same subjects, the authors also investigated whether practice of yoga had any neuroprotective effect by comparing age-related gray matter decline. Interestingly, their findings showed no age-related decline in whole brain gray matter density when compared with healthy controls, which showed atrophy effects of healthy aging in brain¹¹.

Though these studies are promising and validate scientifically the effect of yoga on Neuroanatomical Plasticity, there is still scope for well-planned, randomised, controlled and longitudinal studies with greater sample size to increase statistical power of the data. Moreover, future studies need to examine potential effects of yoga to maintain and improve cognitive health across the lifespan through longitudinal and intervention studies.

I hope you enjoy reading this article and after knowing how yoga can change your brain for good, it motivates you for daily practice! In the next article, I will cover the science behind the effect of Yoga on functional and metabolic changes in brain.

If you found the article of interest or have thoughts about what you’ve read here, please do share in the comments section below. It will help guide my future posts.

1. Maddock, R.J. et al. Acute Modulation of Cortical Glutamate and GABA Content by Physical Activity. Journal of Neuroscience 24 (2016)

2. Li, Hq., Spitzer, N.C. Exercise enhances motor skill learning by neurotransmitter switching in the adult midbrain. Nat Commun11, 2195 (2020)

3. Physical Activity Guidelines Advisory Committee Report. (2008) Washington, DC: U.S. Dept of Health and Human Services; 2008.

4. Ross A, Thomas S. The health benefits of yoga and exercise: a review of comparison studies. J Altern Complement Med. (2010) Jan;16(1):3-12.

5. Froeliger, Brett et al. Yoga meditation practitioners exhibit greater gray matter volume and fewer reported cognitive failures: results of a preliminary voxel-based morphometric analysis. Evidence-based complementary and alternative medicine : eCAM vol. 2012 (2012)

6. Villemure C., Ceko M., Cotton V.A., Bushnell M.C. Insular cortex mediates increased pain tolerance in yoga practitioners. Cereb Cortex. 2014;24:2732–2740

7. Santaella D.F., Balardin J.B., Afonso R.F., Giorjiani G.M., Sato J.R., Lacerda S.S., Amaro E., Jr., Lazar S., Kozasa E.H. Greater Anteroposterior Default Mode Network Functional Connectivity in Long-Term Elderly Yoga Practitioners. Front. Aging Neurosci. 2019

8. Afonso R.F., Balardin J.B., Lazar S., Sato J.R., Igarashi N., Santaella D.F., Lacerda S.S., Amaro E., Jr., Kozasa E.H. Greater Cortical Thickness in Elderly Female Yoga Practitioners-A Cross-Sectional Study. Front. Aging Neurosci. 2017

9. Gothe N.P., Hayes J.M., Temali C., Damoiseaux J.S. Differences in Brain Structure and Function Among Yoga Practitioners and Controls. Front. Integr. Neurosci. 2018

10. Hariprasad V.R., Varambally S., Shivakumar V., Kalmady S.V., Venkatasubramanian G., Gangadhar B.N. Yoga increases the volume of the hippocampus in elderly subjects. Indian J. Psychiatry. 2013

11. Villemure C., Čeko M., Cotton V.A., Catherine Bushnell M. Neuroprotective effects of yoga practice: Age-, experience-, and frequency-dependent plasticity. Front. Hum. Neurosci. 2015