A 2013 study published in PLOS ONE examined how yoga affects the immune system at the molecular level. Researchers compared experienced yoga practitioners with a control group after a retreat-style intervention. The yoga group showed changes in the expression of 111 genes related to immune function. The control group showed changes in only 38.
The affected genes were involved in inflammatory pathways, stress response, and cellular aging. The findings suggest that yoga does not simply reduce the subjective feeling of stress. It appears to influence the biological mechanisms that govern immune response and inflammation.
This type of research moves the conversation about yoga beyond psychology and into molecular biology. The changes were not in how people felt about their immune system. They were in how their cells were actually functioning. Regular practice appears to shift gene expression in directions associated with health and longevity.
Source: Yoga Research: Immunity & General Health on ashtanga.tech. Original research.