Files
Abstract
This dissertation involved two investigations. First, a systematic review and meta-analysis estimated the population effect size of yoga interventions for reducing pain in randomized controlled trials with samples of people in chronic pain. Forty-five effects were derived from 12 experiments; 1680 patients (mean ±SD sample size: 70±30) categorized as having chronic low back pain, chronic neck pain, migraines, cancer-related pain, arthritis, fibromyalgia, neck pain, or neuropathic pain. Thirty-seven of 45 (82%) effects were greater than zero. Unweighted Hedge’s d effect sizes ranged from -0.93 to 6.46. Compared to non-yoga control conditions, yoga training significantly reduced pain symptoms among those in chronic pain by a large mean effect (∆) of 1.31 (95%CI: 0.79 to 1.83, Z = 4.92, p < 0.001) and improved physical disability by a moderate mean effect (∆) of .56 (95%CI: 0.11 to 1.02, Z = 2.41, p = 0.016).
The aim of the second experiment was to test, using a post-test only between-subjects design, main and interactive effects of yoga and slow breathing on both sensitivity to heat pain and endogenous pain modulation in healthy young women.
Fifty-four women were randomized into one of four 40-minute conditions: yoga with slow breathing instructions (Vinyasa), yoga with no breathing instructions, seated rest with slow breathing instructions and seated rest with no breathing instructions. Two factor ANOVA showed that yoga postures and slow breathing, and their interaction were statistically insignificant for both sensitivity to heat pain and endogenous pain modulation. These findings were unchanged in ANCOVAs that controlled for four potential confounding variables: post-condition reduction in systolic blood pressure or state anxiety, pain induced by the conditions and expectations. Compared to the non-yoga conditions, the yoga conditions resulted in a significant reduction in state anxiety scores.
It is concluded that 40-minutes of low-to-moderate intensity yoga with, or without slow breathing, reduces state anxiety but has no effect on heat pain sensitivity or endogenous pain modulation. The findings support the idea that higher intensity yoga which produces moderate intensity pain may be necessary to alter heat pain sensitivity and endogenous pain modulation.
The aim of the second experiment was to test, using a post-test only between-subjects design, main and interactive effects of yoga and slow breathing on both sensitivity to heat pain and endogenous pain modulation in healthy young women.
Fifty-four women were randomized into one of four 40-minute conditions: yoga with slow breathing instructions (Vinyasa), yoga with no breathing instructions, seated rest with slow breathing instructions and seated rest with no breathing instructions. Two factor ANOVA showed that yoga postures and slow breathing, and their interaction were statistically insignificant for both sensitivity to heat pain and endogenous pain modulation. These findings were unchanged in ANCOVAs that controlled for four potential confounding variables: post-condition reduction in systolic blood pressure or state anxiety, pain induced by the conditions and expectations. Compared to the non-yoga conditions, the yoga conditions resulted in a significant reduction in state anxiety scores.
It is concluded that 40-minutes of low-to-moderate intensity yoga with, or without slow breathing, reduces state anxiety but has no effect on heat pain sensitivity or endogenous pain modulation. The findings support the idea that higher intensity yoga which produces moderate intensity pain may be necessary to alter heat pain sensitivity and endogenous pain modulation.