Yoga is good for your brain, scientists from University of Illinois and Wayne State University have found, with positive benefits for memory, decision-making and emotional health.
They analysed the results from 11 studies, which included five that featured individuals with no experience of yoga. In these five, which took place over 10-24 weeks, the scientists compared brain health at the beginning and end of the intervention. The other studies measured brain differences between individuals who regularly practise yoga and those who don’t.
All the participants did Hatha yoga, which includes body movements, meditation and breathing exercises, and each of the 11 studies used brain-imaging techniques such as MRI, functional MRI or single-photon emission computerised tomography.
“From these 11 studies, we identified some brain regions that consistently come up, and they're surprisingly not very different from what we see with exercise research,” said lead author Neha Gothe from the University of Illinois.
“For example, we see increases in the volume of the hippocampus with yoga practice. Many studies looking at the brain effects of aerobic exercise have shown a similar increase in hippocampus size over time. The hippocampus is involved in memory processing and is known to shrink with age. It's also the structure that's first affected in dementia and Alzheimer’s disease.”
However, the hippocampus is not the only brain structure that benefits from yoga, says fellow author Jessica Damoiseaux, a psychology professor at Wayne State University: "Though many of the studies are exploratory and not conclusive, the research points to other important brain changes associated with regular yoga practice. The amygdala, a brain structure that contributes to emotional regulation, tends to be larger in yoga practitioners than in their peers who don't practise 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 practise 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. The default mode network is a set of brain regions involved in thinking about the self, planning and memory.
"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."
The studies also found that the brain changes seen in individuals practising yoga are associated with better performance on cognitive tests or measures of emotional regulation.
“Yoga isn't aerobic in nature, so there must be other mechanisms leading to these brain changes,” said Gothe. “So far, we don’t have the evidence to identify what those mechanisms are."
She suspects that enhancing emotional regulation is 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.