-200 were assessed for eligibility and 34 completed study
-the study controlled for group effects and interaction time by researchers?-I would have liked to see more detail hereYoga: teachers interaction with students and students interaction with each otherWalking: were participants allowed to chat? Music?Were the sessions of yoga conducted in the same room as the walking?What season was it? Did the 12 weeks span summer versus winter?
Not a robust enough study-age range narrow-majority female-well educated-PARs: Physical activity recall: used to convert subject’s weekly physical activity outside of the intervention into a METs score: PAR higher for walking group p-value is the probability of obtaining a test statistic at least as extreme as the one that was actually observed, assuming that the null hypothesis is true. One often "rejects the null hypothesis" when the p-value is less than the significance level α (Greek alpha), which is often 0.05 or 0.01. When the null hypothesis is rejected, the result is said to bestatistically significant.The t-test assesses whether the means of two groups are statistically different from each other. This analysis is appropriate whenever you want to compare the means of two groups, and especially appropriate as the analysis for the posttest-only two-group randomized experimental design.
In statistics, a generalized estimating equation (GEE) is used to estimate the parameters of a generalized linear model with a possible unknown correlation between outcomes.
Did the authors of this study consider the meditation aspect of Iyengar yoga to be the key to the mood elevation rather than the yoga stretches themselves? -no but from my reading of the article I think the subjects were just asked to do poses2) The authors asked the subjects to rate their mood and anxiety, measuring if they feel revitalization, tranquility and anxiety. The environment can play a big role here, was this put into consideration? If not, should they? For example, walking outside at the park vs. On the treadmill or doing yoga with relaxing music. -the walking group walked in the gym and on the treadmill before for scan 2 and 3 -article did not indicate where the yoga classes took place3) The mean age of the subjects were 23.9 for yoga group and 25.6 for the walking group. Does this method possible work best for younger age groups, familiarized with yoga’s relaxing effects through popular culture? Will there be the same effect if done in an old cohort? -further studies need to be done for a wider age group -BKS Iyengar is 914) GABA levels can be affect by diet, was this considered (other than alcohol consumption)? How do the subjects’ diets differ? (i.e. Vegetarian? Vegan?) -no researchers did control for diet -some studies have been done to show that foods affect GABA levels: AlmondsTreenutsBananasBeefLiverBroccoliBrownRiceHalibutLentilsOats, whole grainOranges, citrus fruitsRicebranSpinachWalnutsWhole wheat, whole grains5) In the future, if a yoga program was implemented for depression or anxiety patients, will there be an issue to have them comply to going to a 12-week long intervention? -yes, compliance would be an issue -unless you did a residential study
Effects of yoga versus walking on mood,
Effects of Yoga Versus Walking on Mood, Anxiety, and Brain GABA Levels Presented by: Julia Ho, March 7, 2012
Streeter et al. (2010). Effects of Yoga Versus Walking onMood, Anxiety, and Brain GABA Levels: A RandomizedControlled MRS Study., The Journal of Alternative andComplementary Medicine, 16(11), 1145-1152.
Background -previous studies of yoga as a therapeutic intervention for anxiety, epilepsy and depression Khalsa, S. Yoga as a therapeutic intervention: A bibliometric analysis of published research studies. Indian Journal of Physiology and Pharmacology, 2004. Craft, L.L. and Landers, D.M. The effect of exercise on clinical depression and depression resulting from mental illness: A meta-analysis. Journal of Sports and Exercise Psychology, 1998. Yardi, N. Yoga for control of epilepsy. Seizure, 2001.
Background Large body of research on the beneficial effects of exercise on depression and anxiety Craft, L.L., Landers D.M. The effect of exercise on clinical depression and depression resulting from mental illness: A meta-analysis. Journal of Sports Exercise Psychology, 1998.
Background Medications which increase γ-Aminobutyric acid (GABA) activity in the brain are used in depression and anxiety treatment Vallium and Librium bind to the same neuroreceptors which GABA bind to GABA is a neurotransmitter in the brain which functions to inhibit activity in neurons
Objectives Are changes in mood, anxiety and GABA levels are specific to yoga or related to physical activity?
Methodology Subjects recruited from the Boston area community by newspaper ads, flyers and Internet Eligibility: healthy subject with no significant medical/psychiatric disorders, 18-45 years old Exclusionary criteria: any yoga practice in the previous 3 months or a lifetime history of one yoga session/week for ≥4 weeks, current participant in psychotherapy, prayer groups, or mind-body disciplines, neurological disorders or medical condition that would compromise subject safety, treatment within the previous 3 months with meds that might affect the GABA system, alcohol consumption > 4 drinks/day and contraindication to magnetic resonance evaluation
Methodology Experimental design: clinical trial type study testing treatment interventions Independent variables: Walking intervention, Yoga intervention Iyengar Yoga sessions: 60-min, 3x/wk (equivalent to 3.0 METs) Walking sessions: 60-min, 3x/wk, 2.5 miles per hour on a flat surface (equivalent to 3.0 METs) N.B.: METs (metabolic equivalents) are used to rate and compare the physical demands of various activity by the American College of Sports Medicine
Methodology Dependent variable 1: GABA level All subject had three magnetic resonance spectroscopy (MRS) to obtain GABA levels Scan 1 at baseline Scan 2 after 12-week intervention was followed by 60-min yoga or walking intervention which was followed by Scan 3 Dependent variable 2: Mood and anxiety scales Taken at weeks 0, 4, 8 and 12 and before each MRS Mood scale: Exercise Induced Feeling Inventory (EIFI) Positive Engagement, Revitalization, Tranquility and Physical Exhaustion Anxiety Scale: State scale of the Spielberger State-Trait Anxiety Inventory (STAI)
Methodology Yoga intervention format: Certified Iyengar yoga instructors taught the yoga interventions which were monitored for consistency by the researchers Walking intervention structure: group sessions which sessions walked around the gym perimeter Between scan 2 and 3, the subjects walked on a treadmill set to 2.5 mph with 0 incline
Results Statistical analysis on: A GEE (generalized estimating equation) model for changes in mood and anxiety scores for each group at weeks 0, 4, 5 and 12 Tonic changes in GABA levels: subtracting Scan 1 from Scan 2 values; acute changes in GABA level: subtracting Scan 2 from Scan 3 values Tonic and Acute changes in GABA levels Correlations of mood and anxiety scores with GABA levels for each scan Correlations of tonic and acute changes in mood and anxiety scores with tonic and acute changes in GABA levels
Results Main findings: the 19 yoga subjects reported greater improvement in mood and greater decreases in anxiety than the 15 subjects in the walking group There were positive correlations between improved mood and decreased anxiety and thalamic GABA levels The yoga group had positive correlations between changes in mood scales and changes in GABA levels
Discussion Limitations of the study: Significantly greater level of physical activity level outside the intervention in the walking group compared to the yoga group The higher level of outside activity in the walking group could have contributed to the finding of smaller changes in mood and anxiety in the walking group as the intervention may not have been great enough physical challenge given the greater level of outside activity
Discussion First study to demonstrate that increased thalamic GABA levels are associated with improved mood and decreased anxiety Effect of yoga intervention on GABA levels may be due to the ability of yoga practices to increase parasympathetic nervous activity Merits future study of yoga on mood disorders and other neurotransmitters e.g. norepinephrine and sertonin
Conclusion Depression is one of the most common mental health disorders Canadians being diagnosed and treated for depression: 2.72 million in 1993 to 7.8 million in 2000. Amount spent on antidepressants rose from $161 million in 1993 to $543 million in 2000.* Implications of future research into yoga intervention in the treatment of depression could lead to significant cost savings and a more generalized acceptance of alternative treatments in the healthcare system *Source: IMS Health statistics