Pioneer guided imagery researchers from Ohio State University College of Medicine in Columbus, Ohio, examined whether the practice of hatha yoga can reduce stress responses, as indicated by measurable inflammatory and endocrine shifts in the body immediately after a session. This study compares the reactions of novice and expert yoga practitioners before, during, and after a restorative hatha yoga session, as compared to two control conditions.
Stressors were imposed on the subjects before each of the three
conditions in order to provided data on the extent to which the yoga
accelerated physiological recovery from the heightened stress.
A total of 50 healthy women (mean age, 41.32 years; range, 30-65 years), 25 novices and 25 experts, were all exposed to each of the conditions (yoga, movement control, and passive-video control) during three separate visits.
The single yoga session boosted participants' positive affect (mood). compared with the control conditions, but no overall differences in inflammatory or endocrine responses were unique to the yoga session.
More importantly, even though novices and experts did not differ on key variables, including age, abdominal fat or cardio-respiratory fitness, the novices' serum interleukin (IL)-6 levels were 41% higher than those of the experts across sessions, and the odds of a novice having detectable C-reactive protein (CRP) were 4.75 times as high as that of a yoga expert.
These consistent differences in stress responses between the experts and the novices provided a plausible mechanism for their divergent serum IL-6 data, as experts produced less lipopolysaccharide-stimulated IL-6 in response to the stressor than the novices, and IL-6 promotes CRP production.
The study concludes that the ability to minimize inflammatory responses to stressful encounters influences the burden that stressors place on an individual. If yoga dampens or limits stress-related changes, then regular practice could have substantial health benefits.