Predictors of adherence to a 26-week viniyoga intervention among post-treatment breast cancer survivors.

OBJECTIVES: This study aimed to identify demographic, psychological, health-related, and geographic predictors of adherence to home-based and supervised components of a yoga intervention in breast cancer survivors. METHODS: Participants were the 32 post-treatment breast cancer survivors who were randomized to the Viniyoga intervention arm of a controlled trial. Participants were asked to practice yoga 5 times per week for 6 months, including at least one weekly facility-based session. Adherence was monitored using sign-in sheets and logs. Height and weight were measured; other potential predictors of adherence were obtained from baseline questionnaires. RESULTS: Participants attended 19.6±13.0 yoga classes and performed 55.8±32.8 home-based yoga sessions. Participants adhered to 58% of the overall yoga practice goal (75% of the goal for yoga classes and 54% of the goal for home based-sessions). Higher class attendance and home practice were predicted by greater self-efficacy for yoga (p=0.004 and 0.06, respectively). Additionally, employment outside the home was associated with greater class attendance (p=0.004), while higher waist circumference was marginally associated with lower adherence to home-based yoga (p=0.05). CONCLUSIONS: High levels of facility- and home-based yoga practice were achieved. Breast cancer survivors who have lower self-efficacy for yoga or who have a higher waist circumference may benefit from additional support or intervention tailoring. Adherence may also be improved by ensuring that class times are convenient to both working and nonworking women.

Mediators of yoga and stretching for chronic low back pain.

Although yoga is an effective treatment for chronic low back pain, little is known about the mechanisms responsible for its benefits. In a trial comparing yoga to intensive stretching and self-care, we explored whether physical (hours of back exercise/week), cognitive (fear avoidance, body awareness, and self-efficacy), affective (psychological distress, perceived stress, positive states of mind, and sleep), and physiological factors (cortisol, DHEA) mediated the effects of yoga or stretching on back-related dysfunction (Roland-Morris Disability Scale (RDQ)). For yoga, 36% of the effect on 12-week RDQ was mediated by increased self-efficacy, 18% by sleep disturbance, 9% by hours of back exercise, and 61% by the best combination of all possible mediators (6 mediators). For stretching, 23% of the effect was mediated by increased self-efficacy, 14% by days of back exercise, and 50% by the best combination of all possible mediators (7 mediators). In open-ended questions, ≥20% of participants noted the following treatment benefits: learning new exercises (both groups), relaxation, increased awareness, and the benefits of breathing (yoga), benefits of regular practice (stretching). Although both self-efficacy and hours of back exercise were the strongest mediators for each intervention, compared to self-care, qualitative data suggest that they may exert their benefits through partially distinct mechanisms.

Randomized controlled pilot trial of yoga in overweight and obese breast cancer survivors: effects on quality of life and anthropometric measures.

PURPOSE: To obtain estimates of time to recruit the study sample, retention, facility-based class attendance and home practice for a study of yoga in breast cancer survivors, and its efficacy on fatigue, quality of life (QOL), and weight change. METHODS: Sixty-three post-treatment stages 0-III borderline overweight and obese (body mass index ≥ 24 kg/m(2)) breast cancer survivors were randomly assigned to a 6-month, facility- and home-based viniyoga intervention (n = 32) or a waitlist control group (n = 31). The yoga goal was five practices per week. Primary outcome measures were changes in QOL, fatigue, and weight from baseline to 6 months. Secondary outcomes included changes in waist and hip circumference. RESULTS: It took 12 months to complete recruitment. Participants attended a mean of 19.6 classes and practiced at home a mean of 55.8 times during the 6-month period. At follow-up, 90% of participants completed questionnaires and 87% completed anthropometric measurements. QOL and fatigue improved to a greater extent among women in the yoga group relative to women in the control group, although no differences were statistically significant. Waist circumference decreased 3.1 cm (95% CI, -5.7 and -0.4) more among women in the yoga compared with the control group, with no difference in weight change. CONCLUSIONS: This study provides important information regarding recruitment, retention, and practice levels achieved during a 6-month, intensive yoga intervention in overweight and obese breast cancer survivors. Yoga may help decrease waist circumference and improve quality of life; future studies are needed to confirm these results.

Effects of diets high in walnuts and flax oil on hemodynamic responses to stress and vascular endothelial function.

BACKGROUND: Polyunsaturated fatty acids (PUFA) have beneficial effects on cardiovascular risk, although the mechanisms are incompletely understood. In a previous article, we showed significant reductions in low-density lipoprotein cholesterol and several markers of inflammation with increasing intake of alpha-linolenic acid (ALA) from walnuts and flax. OBJECTIVE: To examine effects of ALA on cardiovascular responses to acute stress, flow-mediated dilation (FMD) of the brachial artery, and blood concentrations of endothelin-1 and arginine-vasopressin (AVP). DESIGN: Using a randomized, crossover study design, cardiovascular responses to acute stress were assessed in 20 hypercholesterolemic subjects, a subset of whom also underwent FMD testing (n  =  12). Participants were fed an average American diet (AAD) and 2 experimental diets that varied in the amount of ALA and linoleic acid (LA) that they contained. The AAD provided 8.7% energy from PUFA (7.7% LA, 0.8% ALA). On the LA diet, saturated fat was reduced, and PUFA from walnuts and walnut oil provided 16.4% of energy (12.6% LA, 3.6% ALA). On the ALA diet, walnuts, walnut oil, and flax oil provided 17% energy from PUFA (10.5% LA, 6.5% ALA). RESULTS: The ALA and LA diets significantly reduced diastolic blood pressure (-2 to -3 mm Hg) and total peripheral resistance (-4%), and this effect was evident at rest and during stress (main effect of diet, p < 0.02). FMD increased (+34%) on the diet containing additional ALA. AVP also increased by 20%, and endothelin-1 was unchanged. CONCLUSIONS: These results suggest novel mechanisms for the cardioprotective effects of walnuts and flax, and further work is needed to identify the bioactives responsible for these effects.