The effects of yoga on the brain

“Yoga Effects on Brain Health: A Systematic Review of the Current Literature”

Abstract

Yoga is the most popular complementary health approach practiced by adults in the United States. It is an ancient mind and body practice with origins in Indian philosophy. Yoga combines physical postures, rhythmic breathing and meditative exercise to offer the practitioners a unique holistic mind-body experience. While the health benefits of physical exercise are well established, in recent years, the active attentional component of breathing and meditation practice has garnered interest among exercise neuroscientists. As the scientific evidence for the physical and mental health benefits of yoga continues to grow, this article aims to summarize the current knowledge of yoga practice and its documented positive effects for brain structure and function, as assessed with MRI, fMRI, and SPECT. We reviewed 11 studies examining the effects of yoga practice on the brain structures, function and cerebral blood flow. Collectively, the studies demonstrate a positive effect of yoga practice on the structure and/or function of the hippocampus, amygdala, prefrontal cortex, cingulate cortex and brain networks including the default mode network (DMN). The studies offer promising early evidence that behavioral interventions like yoga may hold promise to mitigate age-related and neurodegenerative declines as many of the regions identified are known to demonstrate significant age-related atrophy.

https://content.iospress.com/articles/brain-plasticity/bpl190084

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Damn,
I did daily yoga for a ± 4 months earlier this year,
but stopped when I started doing some other exercise…

That’s a kick in the butt to get out of my laziness habits, thanks! x)

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Note: no original research was done by the team. They analysed and correlated dozens of reports by other researchers.

The following key points relate only to “what’s in it for me personally?”

The bullets are in the same sequence as in the source text. But each bullet is independent from a previous bullet. For example, if the word “also” appears in a bullet, it does not mean that the bullet follows on from a previous bullet - it simply means that I was too lazy to remove the word “also”.

  • Systemic and meta-analytic reviews of randomized control trials have found positive associations between yoga practice and improvements in diabetes [4, 5], cardiovascular function [6], and musculoskeletal conditions [2, 3].

  • There is also considerable evidence for the beneficial effects of yoga practice on mental health including anxiety [9], stress [10, 11] depression [12, 13] and overall mental health [14].

  • Lin and colleagues [15] conducted a meta-analysis assessing the effects of yoga on psychological health, quality of life, and physical health of patients with cancer. They concluded that the yoga groups showed significantly greater improvements in psychological health, as indicated by anxiety, depression, distress, and stress levels, when compared with the waitlist or supportive groups.

  • Yoga’s acute and intervention effects on cognition are evident in a recent meta-analysis [16] which reported moderate effect sizes for attention, processing speed and executive function measures for studies conducted with adult populations.

  • In addition to the physical benefits from sequentially completing the postures, the breathing (pranayama) and meditation exercises included in yoga are practiced to calm and focus the mind and develop greater self-awareness [17]. It is hypothesized that this combination of metacognitive thought and bodily proprioception during yoga practice could generalize to conventionally assessed cognitive functions including attention, memory, and higher-order executive functions.

  • systematic reviews discussed earlier have demonstrated the potential of yoga to improve anxiety, depression, stress and overall mental health.

  • Yoga practitioners exhibited greater cortical thickness, gray matter (GM) volume, and GM density than non-practitioners in a variety of regions.

  • Among yoga-practitioners, a positive relationship between the years of yoga practice and GM volume was also observed in a number of areas.

  • Afonso et al. [23] found differences in cortical thickness among female adults over the age of 60 with 8 or more years of Hatha yoga experience compared to a non-practitioner control group.

  • The yoga-practitioners exhibited greater cortical thickness in an area of the left prefrontal cortex that included part of the middle frontal and superior frontal gyri.

  • We found the volume of the left hippocampus [which plays an important role in memory,] to be significantly greater among yoga-practitioners compared to age- and sex- matched controls with similar physical activity and fitness levels.

  • another study [25] also identified volume differences in the left hippocampus and parahippocampal gyrus between healthy adults with and without yoga experience.

  • A number of additional frontal (bilateral orbital frontal, right middle frontal, and left precentral gyri), temporal (left superior temporal gyrus), limbic (left parahippocampal gyrus, hippocampus, and insula), occipital (right lingual gyrus), and cerebellar regions were also larger among yoga-practitioners than non-practitioners.

  • this sample of yoga-practitioners reported fewer cognitive failures than their yoga-naïve counterparts,

  • the researchers correlated the number of lapses in cognitive function that participants reported with the volume of regions where group differences were observed. A negative correlation was reported, such that higher numbers of cognitive failures were associated with smaller GM volumes in the frontal, limbic temporal, occipital, and cerebellar regions

  • After identifying regions of the brain in which yoga-practitioners exhibited greater GM volume than non-practitioners, Froeliger and colleagues (25) looked within these regions to identify areas where years of yoga practice was correlated with GM volume. They found that the extent of yoga experience within yoga-practitioners was positively related to volume of frontal, limbic, temporal, occipital, and cerebellar regions, while no regions showed a negative association between years of yoga practice and GM volume. [Summarizing this bullet: volume of gunk in some parts of the brain correlates with number of years of yoga. No negative correlation was found in any of the other parts]

  • [the following is my summary of a long analysis]. For the yoga practitioners, the volume of some parts of the brain correlates with number of years. For other parts of the brain, the volume correlates to the weekly number of hours. [I’ll try to get my head round that later - it’s getting late here.]

  • our own work [24] evaluated how yoga-practitioners and non-practitioners differed in brain function during subcomponents of a Sternberg working memory task. No differences between the groups were identified during the maintenance or retrieval portions of the task, but yoga-practitioners exhibited significantly less brain activation in the left dorsolateral prefrontal cortex (dlPFC) during encoding compared to yoga-naïve controls. [To my simple mind, that’s saying that yoga does not improve the ability to retrieve stuff from working memory. Nor does it improve the ability to maintain stuff. (I think that means repetition during whatever time is available for repetition before it becomes necessary to retrieve.) However, encoding is faster. Presumably that might mean something like decisions on “shall I chunk this way or that way”]

You can see that my bullets are getting longer. That means I don’t trust myself to be able to extract small relevant snippets, without omitting important stuff.

The analysis is moving on from simple stuff such as “volume of gunk” and “number of years”. Now they begin to talk about tests on brain functions.

All I’m prepared to say is that the positive tone is continuing with no adverse consequences.

If anyone wants to continue, they can search for “Task-related fMRI findings”, and continue reading from there.

Thanks.

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