Role of yoga in preventing and controlling Type 2 diabetes

Yoga has been suggested as a complementary and alternative form of treatment for Type 2 diabetes. It offers the advantages of being cost effective and free from any adverse effects. The purpose of this study was to review studies that have used yoga in preventing or controlling diabetes. The inclusion criteria were studies: (1) conducted between 1993 and 2011; (2) published in English language; (3) that used yoga asanas, or pranayama, or dhyana as the intervention; (4) that involved diabetic patients, healthy volunteers with insulin or glucose levels as outcomes or people at risk for diabetes such as those suffering from metabolic syndrome; (5) that utilized any quantitative design; and (6) that had biochemical, physiological, anthropometric, or clinical outcomes. Excluded were studies that were qualitative or review articles, studies before 1993 or after December 2011, and studies in language other than English. A total of 16 studies met the inclusion criteria. Of these five utilized randomized controlled design, four utilized quasi-experimental design, and seven used pre-test post test design. Fifteen of these studies used yoga asanas, 12 used pranayama, and one each used shatkriyas (cleansing exercises) and yoga nidra (relaxation). The duration of yoga intervention ranged from 8 days to 24 weeks. Of the eleven studies that measured changes in fasting blood glucose nine were able to show significant decrease. Some of the limitations of these interventions have been lack of theory based approach in teaching yoga, small sample sizes, and inability to gauge adherence to yoga practices.