Restorative yoga and metabolic risk factors: the Practicing Restorative Yoga vs. Stretching for the Metabolic Syndrome (PRYSMS) randomized trial.

AIMS: Intensive lifestyle change prevents type 2 diabetes but is difficult to sustain. Preliminary evidence suggests that yoga may improve metabolic factors. We tested a restorative yoga intervention vs. active stretching for metabolic outcomes. METHODS: In 2009-2012, we conducted a 48-week randomized trial comparing restorative yoga vs. stretching among underactive adults with the metabolic syndrome at the Universities of California, San Francisco and San Diego. We provided lifestyle counseling and a tapering series of 90-min group classes in the 24-week intervention period and 24-week maintenance period. Fasting and 2-h glucose, HbA1c, triglycerides, HDL-cholesterol, insulin, systolic blood pressure, visceral fat, and quality of life were assessed at baseline, 6- and 12-months. RESULTS: 180 participants were randomized and 135 (75%) completed the trial. At 12 months, fasting glucose decreased more in the yoga group than in the stretching group (-0.35 mmol/L vs. -0.03 mmol/L; p=0.002); there were no other significant differences between groups. At 6 months favorable changes within the yoga group included reductions in fasting glucose, insulin, and HbA1c and an increase in HDL-cholesterol that were not sustained at 1 year except changes in fasting glucose. The stretching group had a significant reduction in triglycerides at 6 months which was not sustained at 1 year but had improved quality of life at both time-points. CONCLUSIONS: Restorative yoga was marginally better than stretching for improving fasting glucose but not other metabolic factors.