If we’re finished obsessing about yoga jeans, perhaps it’s time to think about yoga and genes.

Newly published research from Norway suggests that a comprehensive yoga program rapidly produces internal changes on a genetic level. The results help explain the well-documented health benefits of this ancient practice.

“These data suggest that previously reported (therapeutic) effects of yoga practices have an integral physiological component at the molecular level, which is initiated immediately during practice,” writes a research team led by Fahri Saatcioglu of the University of Oslo. The team’s study is published in the online journal PLOS ONE.

Researchers first reported five years ago that practices such as yoga which elicit the “relaxation response” may have a long-term effect on gene expression. That’s the scientific term for whether a specific gene is “turned on,” meaning its protein or RNA product is being made. This latest study confirms those findings, links them to the body’s immune system, and suggests this effect may be instantaneous.

The University of Oslo experiment featured 10 participants who attended a week-long yoga retreat in Germany. For the first two days, participants spent two hours practicing a comprehensive yoga program including yogic postures (asanas), yogic breathing exercises (in particular Sudarshan Kriya), and meditation. For the next two days, they spent that same time period going on an hour-long nature walk and then listening to either jazz or classical music.

Immediately before and after each of the four sessions, the researchers drew blood from each participant. They then isolated and analyzed peripheral blood mononuclear cells, which play a key role in the body’s immune system. The researchers found that the nature walk and music-driven relaxation changed the expression of 38 genes in these circulating immune cells. In comparison, the yoga produced changes in 111.

Fourteen genes were affected by both exercises, which suggests “the two regimens, to some degree, affect similar biological processes,” the researchers write. That said, they note that yoga’s impact was far more widespread, which indicates the practice “may have additional effects over exercise plus simple relaxation in inducing health benefits through differential changes at the molecular level.”

So, if your yoga mat has been gathering dust, this research provides an incentive to take it out of the closet. It suggests that, as far as the immune system is concerned, walking in nature is good—but yoga might be substantially better.

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