Genetic Expression Changes Immediately After Yoga Practice
Article Review by Dr. Stephanie Shorter
Qu S, Olafsrud SM, Meza-Zepeda LA, Saatcioglu F (2013). Rapid Gene Expression Changes in Peripheral Blood Lymphocytes upon Practice of a Comprehensive Yoga Program. PLoS ONE 8(4): e61910. doi:10.1371/journal.pone.0061910
Last week, a group of Norwegian bioscience researchers published a new paper that points to a molecular basis for the immediate feel-good effects of practicing yoga. Qu et al. (2013) studied how gene expression quickly changes in lymphoctyes (immune system cells) in the circulating bloodstream of yoga practitioners.
Genetic data from 10 healthy men (ages 18-50) was analyzed for this study, which was part of a weeklong yoga retreat in Germany. The yoga (experimental) intervention involved a morning practice of Sudarshan Kriya Yoga (SKY) on two consecutive days. The standardized practice sessions were termed a ‘complete yoga practice’ as they involved gentle yoga asanas, pranayama and Sudarshan Yoga breathing (a rhythmic breathing technique) and ended with meditation. Participants were all regular SKY practitioners with 1.5 to 5 years of experience. The control condition in this study involved two parts: walking outside in nature (to emulate the physical exercise component of yoga) and listening to calming music (to tap into the relaxation response).
SKY is a heavily breath-based intervention and it is claimed to eliminate stress and negative emotions while boosting energy and focus. Using a SKY protocol, several past studies have showed both physical and benefits – from improving antioxidation in cells, to decreasing acidity of the blood, to relieving depression and anxiety. (Patricia Gerbarg and Richard Brown are experts in the latter and their work, which ranges from PTSD and natural disasters field to clinical techniques is highly recommended for further reading.)
Heatmaps of differentially expressed genes for the yoga condition (upper panel) and the control condition (lower panel). Each row represents a different gene and the color expresses the change in its expression. Each column represents one participant in one condition (see paper for more detail). A red square indicates up-regulation and a green square indicates down-regulation. The Venn diagram shows the number of unique and overlapping genes implicated in the two conditions.
Qu et al. took blood samples from the male participants before and after each condition. Yoga sessions were on the first two days and the walking/relaxation control sessions were held at the same time and place on the third and fourth days of the retreat. Immune cells (peripheral blood mononuclear cells) were extracted from each blood sample. Earlier research has established long-term gene expression changes in SKY, Qigong and meditation practitioners. However, it remains to be seen how quickly gene expression can change after a mind-body practice session. This study is the first to take blood samples daily after practice and look for how soon the genetic change starts to occur.
Results: Gene Expression Changes in Just Two Hours
Measurable differences started occurring in the genes of immune cells within just one session (i.e., two hours of yoga practice). There were three times the number of differentially expressed genes following the yoga sessions as compared to the control condition; the SKY condition induced a change in 111 genes, whereas the control condition saw a modification in 38 genes. Of these genes, 14 were similarly affected in both the yoga and control conditions. The yoga condition equally up-regulated and down-regulated genes. For the control condition, on the other hand, it was significantly more likely that genes were down-regulated. Up-regulation and down-regulation are processes in which the gene expression and its related cascade of protein synthesis events are either enhanced or turned off. In a nutshell, the results show that yoga turns on protein synthesis more than walking and relaxation.
Questions for the Future
It is a bit of a leap at this point to jump from these gene expression results to better function of the immune function. That is, we know that the genes are starting to change, but it is an unknown when cell morphology and physiology follows suit and the timeline to when there is a measureable difference in immunity. Seeing a change in a gene does not mean an instantaneous change in function. A very common duration for many yoga studies is 8 weeks, so we know that some functional changes happen in less than 8 weeks. Daily monitoring in a future study will be needed to show the average minimal amount of practicing yoga that, much like crossing a threshold, is sufficient to start changing gene expression in novices who are just getting exposed to yoga.
A methodological limitation, which the authors also mention, is that the two conditions should have been randomized across the participants. The yoga sessions (Y) happened for two days and then the walking/relaxation control sessions (C) happened for the next two days. This must have been done for practical reasons within the retreat. However, it is bad form in terms of experimental design. Ideally, a few participants (and more participants added if we’re really making a wish list here!) would have been randomized to every possible order: YYCC, CCYY, YCYC, YCCY, CYCY, and CYYC. This counterbalancing would help us rule out potential confounds.
As is, the set order of YYCC for all participants begs the question of whether there was a carryover effect that went into the third (or even fourth) day and leaves the possibility open for conditioned relaxation responses being learned from the yoga days and extending into the control days. This would be a form of classical conditioning (yes, just like Pavlov’s salivating dogs). The potency of conditioning physiology to a specific room is not to be taken lightly. (In fact, drug overdoses tend to occur in novel environments for this very reason because the body does not have the external cues that usually trigger a compensatory response before the drug enters the body; the same dose that is OK at home may prove fatal in a strange place.) A space where ones regularly practices yoga begins to take on healing properties by simply being in the room, even when not practicing. This can be useful for a practitioner, but it makes clean measurement much trickier for a yoga researcher.
In the final sentence, the authors raise the interesting idea of using this kind of genetic platform to conduct comparative studies of different types of yoga practice. We have many different labels for many different styles of Hatha Yoga. Gene and protein expression would be the ultimate way to test if there are truly differences in the benefits of practicing each style.
The biology of mind-body medicine is really still a wide-open pasture and we’re still just skirting the fence. Even with its limitations, this study makes an exciting step in moving us closer to understanding the cellular biology of yoga.