Yoga induces a feeling of well-being in healthy people, and can reverse the clinical and biochemical changes associated with metabolic syndrome, according to results of studies from Sweden and India. Metabolic syndrome is a cluster of heart disease risk factors such as high blood pressure, obesity and high blood sugar. Dr. R.P. Agrawal, of the SP Medical College, Bikaner, India, and colleagues evaluated the beneficial effects of yoga and meditation in 101 adults with features of metabolic syndrome.

In the study, 55 adults received three months of regular yoga including standard postures and Raja Yoga, a form of transcendental meditation daily, while the remaining received standard care.

Waist circumference, blood pressure, blood sugar, and triglycerides were significantly lower, and "good" HDL cholesterol levels were higher in the yoga group as compared to controls, Agrawal's team reports in the journal Diabetes Research and Clinical Practice. In the second study, published online December 19 in BioMed Central Complementary and Alternative Medicine, Dr. Anette Kjellgren from the University of Karlstad, Sweden and colleagues evaluated the beneficial effects of yoga-like breathing exercises on healthy volunteers.

Fifty-five adults were advised to practice "Sudarshan Kriya," which involves cycles of slow normal and rapid breathing exercises. The exercises were practiced for an hour daily, six days a week for six weeks, while 48 controls were advised to relax in an armchair for 15 minutes daily.

At the end of the study period, feelings of anxiety, stress and depression were significantly lower and levels of optimism significantly higher in the yoga group compared to the control group, Kjellgren and colleagues report.

Yoga induces a "relaxation response" associated with reduced nervous system activity and a feeling of well-being probably due to an increase in antioxidants and lower levels of the stress hormone cortisol, they suggest. Yoga not only helps in prevention of lifestyle diseases, but can also be "a powerful adjunct therapy when these diseases arise," co-investigator Dr. Faahri Saatiglou, from the University of Oslo, told Reuters Health. "We do not emphasise this point enough in our Western health care."

SOURCES: Diabetes Research and Clinical Practice, December 2007, BMC Complementary and Alternative Medicine, online December 19, 2007.