Yoga provides brain benefits similar to those from aerobic exercise

USA: Aerobic exercise is known to strengthen the brain and contribute to the growth of new neurons. Now, a recent review published in the journal Brain Plasticity has found that brain benefits from yoga are similar to those from aerobic exercise.

According to the study, behavioural interventions like yoga may help to mitigate age-related and neurodegenerative declines. The studies demonstrated a positive effect of yoga practice on the structure and/or function of some brain regions including the hippocampus, amygdala, prefrontal cortex, cingulate cortex, and brain networks.

Yoga is an ancient mind and body practice that has its origin in Indian philosophy and now has spread worldwide owing to its vast health benefits. It combines physical postures, rhythmic breathing and meditative exercise to offer the practitioners a unique holistic mind-body experience. 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 by Neha Gothe, Kinesiology and Community Health, the University of Illinois at Urbana Champaign, Urbana, and colleagues aimed 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. For the purpose, the researchers reviewed 11 studies examining the effects of yoga practice on brain structures, function, and cerebral blood flow

Five of the studies engaged individuals with no background in yoga practice in one or more yoga sessions per week over 10–24 weeks, comparing brain health at the beginning and end of the intervention. The other studies measured brain differences between individuals who regularly practice yoga and those who don’t.

Each of the studies used brain-imaging techniques such as MRI, functional MRI or single-photon emission computerized tomography. All involved Hatha yoga, which includes body movements, meditation and breathing exercises.

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“From these 11 studies, we identified some brain regions that consistently come up, and they are surprisingly not very different from what we see with exercise research,” said University of Illinois kinesiology and community health professor Neha Gothe, who led the research with Wayne State University psychology professor Jessica Damoiseaux.

“For example, we see increases in the volume of the hippocampus with yoga practice,” Gothe said in a press release. Many studies looking at the brain effects of aerobic exercise have shown a similar increase in hippocampus size over time, she said.

The hippocampus is involved in-memory processing and is known to shrink with age, Gothe said. “It is also the structure that is first affected by dementia and Alzheimer’s disease.”

Though many of the studies are exploratory and not conclusive, the research points to other important brain changes associated with regular yoga practice, Damoiseaux said. The amygdala, a brain structure that contributes to emotional regulation, tends to be larger in yoga practitioners than in their peers who do not practice yoga. The prefrontal cortex, cingulate cortex and brain networks such as the default mode network also tend to be larger or more efficient in those who regularly practice yoga.

“The prefrontal cortex, a brain region just behind the forehead, is essential to planning, decision-making, multitasking, thinking about your options and picking the right option,” Damoiseaux said. “The default mode network is a set of brain regions involved in thinking about the self, planning and memory.”

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Like the amygdala, the cingulate cortex is part of the limbic system, a circuit of structures that plays a key role in emotional regulation, learning and memory, she said.

The studies also find that the brain changes seen in individuals practising yoga are associated with better performance on cognitive tests or measures of emotional regulation.

The discovery that yoga may have similar effects on the brain to aerobic exercise is intriguing and warrants more study, Gothe said. “Yoga is not aerobic in nature, so there must be other mechanisms leading to these brain changes,” she said. “So far, we don’t have the evidence to identify what those mechanisms are.”

She suspects that enhancing emotional regulation is a key to yoga’s positive effects on the brain. Studies link stress in humans and animals to shrinkage of the hippocampus and poorer performance on tests of memory, for example, she said.

“In one of my previous studies, we were looking at how yoga changes the cortisol stress response,” Gothe said. “We found that those who had done yoga for eight weeks had an attenuated cortisol response to stress that was associated with better performance on tests of decision-making, task-switching and attention.”

Yoga helps people with or without anxiety disorders manage their stress, Gothe said.

“The practice of yoga helps improve emotional regulation to reduce stress, anxiety and depression,” she said. “And that seems to improve brain functioning.”

The researchers say there is a need for more – and more rigorous – research into yoga’s effects on the brain. They recommend large intervention studies that engage participants in yoga for months, match yoga groups with active control groups, and measure changes in the brain and performance on cognitive tests using standard approaches that allow for easy comparisons with other types of exercise.

“The science is pointing to yoga being beneficial for healthy brain function, but we need more rigorous and well-controlled intervention studies to confirm these initial findings,” Damoiseaux said.

The study, "Yoga Effects on Brain Health: A Systematic Review of the Current Literature," is published in the journal Brain Plasticity.

DOI: 10.3233/BPL-190084