Yoga’s Effect on Inflammatory Biomarkers and Related Disease
A mini-review of the scientific literature explores whether yogic practices are directly linked to reductions in inflammatory biomarkers implicated in a number of physical and mental conditions.
Chronic stress is linked to systemic inflammation, which increases the risk of cardiovascular, musculoskeletal, and gastrointestinal diseases, depression, Alzheimer’s, and Parkinson’s diseases, among others. Systemic inflammation is frequently indicated by the elevated presence of several inflammatory biomarkers, including cortisol, interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-α), blood pressure, and C-reactive protein (CRP).
Several decades of research establish that regular yoga practice is generally effective for managing physiological and psychological stress and its symptoms. More recent studies have examined whether these reductions are also linked to changes in biomarker levels and associated symptom reduction. A recent mini-review explored what we know so far regarding yoga’s impact on inflammatory biomarkers across a number of health domains.
How Yoga Affects Stress Management and Depression
Yoga’s effects on stress management and reducing physiological and psychological stress are well documented. Over the past decade, we have learned that consistent yoga practice may be associated with reductions in stress-related and inflammatory biomarkers, including cortisol, interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-α), and blood pressure. Some of these effects are found to occur within 10 days of beginning a regular yoga practice.
Other systemic reviews of the research have noted that yoga may be effective as an adjunctive therapy for individuals experiencing symptoms of depression. This may be directly linked to reductions in psychological and psychological stress.
These effects are not universal, however. Some studies have failed to detect a link between yoga practice and reductions in stress-related and inflammatory biomarkers or decreases in depression. Inconsistencies in yogic practices and duration of interventions across studies, small sample sizes, and other methodological issues challenge our ability to make definitive conclusions. The general trend of the research is promising and bears further study.
Studies on Yoga and Cardiovascular and Metabolic Diseases
The mini-review examined several small trials that examined direct links between yoga interventions and reductions in biomarkers related to cardiovascular and metabolic disease. Several of these proved promising.
In one study, nine adults with chronic heart failure participating in eight weeks of twice weekly 70-min yoga therapy sessions showed greater reductions in IL-6 and C-reactive protein (CRP), both biomarkers of inflammation, as well as better self-reported quality of life compared to 10 individuals who received traditional medical treatment.
Another study of 83 adults with high blood pressure who were randomly assigned to either weekly yoga classes at home or with an instructor or usual care did not find meaningful differences in either of these inflammatory biomarkers or metabolic risk factors for cardiovascular disease.
Results from an intensive yoga intervention in which 48 adults at risk for metabolic disease were randomly assigned to either an hour, six days per week yoga intervention for three months or a wait-list control group found that yoga group participants showed significant reductions in cholesterol, IL-6, TNF-α, and high sensitivity C-reactive protein levels, suggesting that intensive, regular yoga practice can significantly reduce indicators of inflammation. Authors of the mini-review question whether an intervention of this length and intensity is feasible for western clinical settings.
Given the high variability in the types of yogic strategies used (e.g., asana, pranayama, meditation, lectures), and significant differences in the duration and intensity of interventions across studies, it is difficult to disentangle which aspects of these yoga therapies were most impactful in effecting change in inflammatory biomarkers, or reducing the risk or related symptoms of cardiovascular or metabolic disease.
Yoga and Autoimmune Diseases
Several studies examine the link between yoga practice and autoimmune disorders such as rheumatoid arthritis and inflammatory bowel disease.
In a randomized controlled trial, 72 adults diagnosed with rheumatoid arthritis were assigned to either anti-rheumatic drugs and yoga or drug treatment alone. Those in the yoga group practiced two hours per day, five days a week, for eight weeks. Compared to the control group, yoga participants showed significant decreases in inflammatory biomarkers, including C-reactive protein, IL-6, and TNF-α, as well as an increase in telomerase activity, suggesting that intensive, regular yoga practice may preserve healthy cell function and promote long-term immune functioning. Yoga group members also reported fewer symptoms of depression at the end of the study compared to the control group.
In another study, including 80 individuals with rheumatoid arthritis who were randomly assigned to either a 40-day, six-day-per-week, 90-minute yoga group or a wait-list control group, yoga participants showed significantly reduced C-reactive protein compared to the wait-listed group.
Other interventions have yielded contrary results. For example, when comparing the effects of an eight-week yoga intervention to standard medical therapy, no significant differences were found in inflammatory biomarkers between the intervention and control groups.
The authors of the mini-review concluded that there is insufficient evidence to support a relationship between yoga practice and improvements in stress-related biomarkers for those with autoimmune disorders.
Heart and Immune Function in Older Adults
Immune function in older adults is frequently linked to several age-related degenerative diseases affecting both the mind and body. Two small studies suggest that regular yoga practice can confer reductions in cortisol concentration and secretion in older adults, suggesting a reduced stress response. In another investigation with 14 elderly adults, those who were randomized to a 10-week hatha yoga group showed improvements in inflammatory markers compared to the control group.
On the other hand, 38 older adults who were either randomly assigned to two 90-minute Iyengar yoga sessions weekly for eight weeks, or a control group, showed no significant differences in inflammatory biomarkers. They did show benefits in muscle strength, range of motion, and physical and emotional well-being, which are particularly important for older adults.
Yoga and Breast Cancer
During the past two decades, yoga has become a complementary therapy for alleviating pain and stress for individuals with breast cancer. More recently, researchers have assessed the effects of yoga practice on physiological indicators of inflammation.
In one study, 200 women were randomized to either a yoga intervention twice weekly for 12 weeks or a waitlist control group. Compared to the control group, those in the yoga group had significantly lower inflammatory biomarker levels (IL-6, TNF-α, and IL-1 β) at the end of the study and three months later, suggesting that regular yoga practice may serve as an important adjunctive therapy for reducing inflammation in those undergoing treatment for breast cancer. What’s more, the more frequently an individual practices, the greater the benefit.
Another clinical trial compared the effects of pranayama and relaxation techniques to supportive therapy and exercise rehabilitation on postoperative outcomes in a sample of 98 women awaiting surgery for breast cancer. The control group received emotional support and exercise therapy. Following surgery, the yoga group had better immune responses related to infection and the degree of disease severity, suggesting that regular pranayama and relaxation practice may benefit women with breast cancer awaiting surgery.
Other studies have had mixed results. In one small 12-week randomized controlled trial, 16 women were randomized to a restorative Iyengar yoga intervention and another 15 women to a health education control group. Following the program, there were no differences among yoga and education group participants on biomarkers of stress or inflammation (i.e., C-reactive protein, IL-1, IL-6, or cortisol). A second small study of 20 participants who were randomized to either three hours of yoga weekly or exercise for a period of six months found no significant effects on biomarkers of inflammation.
Pregnancy and Yoga
Prenatal yoga is very popular in the western world for promoting maternal health. Classes are typically tailored to the needs of bodily changes during pregnancy and focus on relaxation and breathing exercises rather than postures. Only one study thus far has examined changes in immune function. This randomized controlled trial included 94 women who were assigned to either 20 weeks of 70-min yoga practice twice weekly, or routine prenatal care that supports stress reduction and enhanced immune function. Results showed evidence of improved immune function and better birth outcomes in the intervention group compared to the control group. Further studies are needed to understand better the impact of these strategies on prenatal and postnatal outcomes.
In Conclusion: Yoga’s Effect on Inflammatory Biomarkers
Overall, this body of research suggests that yoga can be beneficial for reducing inflammatory biomarker levels, particularly IL-6 and IL-1β. These markers are commonly associated with autoimmune diseases such as diabetes and rheumatoid arthritis, with IL-6 also being linked to cancer, obesity, and cardiovascular disease. Reductions in C-reactive protein in some of the studies are also significant, as it is linked to systemic inflammation in illnesses such as depression, cancer, chronic obstructive pulmonary disease (COPD), and obesity.
This review also points to limitations in the current research that will need to be addressed in subsequent studies. Most significantly, the high degree of variability in the duration, length, and techniques used in yoga interventions make it difficult to disentangle which practices are most beneficial, which inflammatory parameters are most impacted, and what amount of yoga is necessary to achieve a benefit. When designed for the individual and administered under the supervision of a qualified professional, yoga shows promise as a lifestyle intervention to reduce systemic inflammation and as a preventative strategy for reducing the likelihood of physical and psychological problems.