Bikram yoga training and physical fitness in healthy young adults

Improvement in muscular strength, body flexibility and balance by yoɡasana and with reduced detraining effects by yoɡa breathing maneuvers: A non-randomized controlled study

BACKGROUND

Yoɡa was reported to have the potential to improve physical fitness. Its applications are being used by common persons for wellness, but literature on the training and detraining effects of components of yoga is scarce.

OBJECTIVES

To explore the potential of different proportions of yoga postures (Yogasana) and yoga breathing maneuvers (YBM), consisting of Pranayama and kriya, on muscular strength, flexibility, and balance in training and detraining management.

METHODS

ː 32 physically active male students, aged 20.5 ± 1.3 yrs, were divided into control (CG) and yoga group (YG). YG practiced yogasana, YBM, and dhyana for 45 min in each session for 6 days per week for 12 weeks. From 1st week to 6th week, they practiced yogasana in greater proportion. 7th week onwards YBM was inducted by increasing its duration and varieties. CG did not practice yoga. Back-leg strength (BLS), Hand Grip Strength (HGS), flexibility, and balance were recorded before, the 6th week and 12th weekend of training.

RESULTS

ː.In YG, the pre-training value of BLS was 110.8 ± 12.6 kg. It increased (2.3 %) to 113.3 ± 11.4 kg (p < 0.001) on the 6th weekend. On the 12th weekend, it further increased in lesser magnitude (0.4 %) to 113.7 ± 11 kg (p < 0.05) and the pattern of improvement was the same in other parameters, but in flexibility and balance its magnitude was greater (p < 0.001). CG did not show such changes.

CONCLUSIONS

ː Yogasana helps in the improvement of muscular strength, flexibility, and balance and YBM counteracts detraining effects in the absence of yogasana. Judiciously selected components of yoga/YBM may have applications in sports, occpational health and recuperative patients.

Role of Yoga in Minimizing Stress and Anxiety in Women Experiencing Dysmenorrhea

Primary dysmenorrhea is characterized by recurring, crampy lower abdominal pain occurring during menstruation in the absence of pelvic pathology. It is the most common gynaecological complaint among adolescents. According to the literature, young females with primary dysmenorrhea experience stress, anxiety, lower-back pain, and depression. Yoga is widely practiced to improve health and promote relaxation. It includes breath regulation, simple meditation, and practicing particular body postures. Regular Yoga practice can serve as an adjunct to the primary treatment of dysmenorrhea symptoms. This study focuses on the impacts and benefits of yoga in young females with dysmenorrhea and associated physiological changes.

Hot Yoga Leads to Greater Well-being: A Six-week Experience-sampling RCT in Healthy Adults

Practicing hot yoga may bring significant psychological benefits, but it is largely unstudied. We examined the effects of hot yoga on multifaceted well-being indicators with 290 healthy yoga-naïve volunteers partaking in a six-week randomized controlled trial. Participants completed questionnaires pre- and post-intervention, and reported their emotional experiences four times per day throughout an experience-sampling study. Results revealed that the hot yoga group (n = 137) improved their well-being from pre- to post-treatment, comparing to the wait-list control group (n = 153). These improvements included life satisfaction, general health, mindfulness, peace of mind, and eudaimonic well-being (ΔR2 ranging from .01 to .08)-but not flourishing, which describes major aspects of social-psychological functioning. Multilevel analyses demonstrated that momentary positive emotional experiences increased significantly throughout the trial in the yoga group only (conditional R2 = .68), particularly when attending a yoga class (conditional R2 = .50). Interestingly, this increase in momentary positive emotion explained the improvement in post-intervention mindfulness, peace of mind, and general health by 21%, 31%, and 11%, respectively. Finally, the benefits of hot yoga were more notable in individuals with lower levels of baseline eudaimonic well-being (conditional R2 = .45), flourishing (conditional R2 = .61), and mental well-being (conditional R2 = .65), even after ruling out any possible ceiling effects. To sum up, this study demonstrated multiple psychological benefits of hot yoga and its potential to be an effective positive psychology intervention. Future research-especially considering an active control group-is warranted.

Effects of a 6 Week Yoga Intervention on Executive Functioning in Women Screening Positive for Adult ADHD: A Pilot Study

Purpose

Little is known about the effects of yoga training in adults with ADHD symptoms. This pilot study sought to determine the feasibility and selected psychological effects of 6 weeks of yoga training in women screening positive for adult ADHD compared to a wait-list control group.

Methods

A randomized trial was conducted with 32 adult women (18–24 years) who volunteered after screening positive for adult ADHD as assessed by the Adult ADHD Self-Report Scale (ASRS). Participants were randomized to 6 weeks of Bikram yoga training or to a wait-list control group. The yoga intervention consisted of two 90-min classes per week. Multilevel models were used to test hypothesized interactions of yoga-induced improvements compared to controls across time (baseline, 3 weeks, and 6 weeks). The primary outcomes assessed inhibitory control, cognitive flexibility and working memory using the NIH Toolbox. Separate models with trait mindfulness, trait anxiety and expectations for change in either attention or working memory as covariates tested whether these variables mediated the changes in the three measures of executive function. Secondary outcomes included mood, perceived functional impairment and motivation for, and hyperactivity during, the cognitive tests.

Results

No adverse events were observed. Attendance averaged 91.7% among the 69% of the sample that did not dropout. No significant Group X Time interactions were found for any of the psychological outcomes and the null executive function findings were unchanged when including the covariates.

Conclusion

Six-weeks of yoga training twice per week is potentially feasible for women experiencing ADHD symptoms, but an exercise stimulus of this duration and magnitude yields no beneficial cognitive or mood outcomes.

Cardiovascular, Cellular, and Neural Adaptations to Hot Yoga versus Normal-Temperature Yoga

CONTEXT

Chronic heat exposure promotes cardiovascular and cellular adaptations, improving an organism's ability to tolerate subsequent stressors. Heat exposure may also promote neural adaptations and alter the neural-hormonal stress response. Hot-temperature yoga (HY) combines mind-body exercise with heat exposure. The added heat component in HY may induce cardiovascular and cellular changes, along with neural benefits and modulation of stress hormones.

AIMS

The purpose of the present study is to compare the cardiovascular, cellular heat shock protein 70 (HSP70), neural, and hormonal adaptations of HY versus normal-temperature yoga (NY).

SETTINGS AND DESIGN

Twenty-two subjects (males = 11 and females = 11, 26 ± 6 years) completed 4 weeks of NY (n = 11) or HY (n = 11, 41°C, 40% humidity). Yoga sessions were performed 3 times/week following a modified Bikram protocol.

SUBJECTS AND METHODS

Pre- and posttesting included (1) hemodynamic measures during a heat tolerance test and maximal aerobic fitness test; (2) neural and hormonal adaptations using serum brain-derived neurotrophic factor (BDNF) and adrenocorticotropic hormone (ACTH), along with a mental stress questionnaire; and (3) cellular adaptations (HSP70) in peripheral blood mononuclear cells (PBMCs).

STATISTICAL ANALYSIS

Within- and between-group Student's t-test analyses were conducted to compare pre- and post-VO2 max, perceived stress, BDNF, HSP70, and ACTH in HY and NY groups.

RESULTS

Maximal aerobic fitness increased in the HY group only. No evidence of heat acclimation or change in mental stress was observed. Serum BDNF significantly increased in yoga groups combined. Analysis of HSP70 suggested higher expression of HSP70 in the HY group only.

CONCLUSIONS

Twelve sessions of HY promoted cardiovascular fitness and cellular thermotolerance adaptations. Serum BDNF increased in response to yoga (NY + HY) and appeared to not be temperature dependent.

Salt and water balance after sweat loss: A study of Bikram yoga

Bikram yoga is practiced in a room heated to 105°F with 40% humidity for 90 min. During the class a large volume of water and electrolytes are lost in the sweat, specifically, sodium is lost, the main cation of the extracellular fluid. There is little known about the volume of sweat and the amount of sodium lost in sweat during Bikram yoga or the optimum quantity of fluid required to replace these losses. The participants who took part in this small feasibility study were five females with a mean age of 47.4 ± 4.7 years and 2.6 ± 1.6 years of experience at Bikram yoga. The total body weight, water consumed, serum sodium concentration, serum osmolality, and serum aldosterone levels were all measured before and after a Bikram yoga practice. Sweat sodium chloride concentration and osmolality were measured at the end of the practice. The mean estimated sweat loss was 1.54 ± 0.65 L, while the amount of water consumed during Bikram yoga was 0.38 ± 0.22 L. Even though only 25% of the sweat loss was replenished with water intake during the Bikram yoga class, we did not observe a change in serum sodium levels or serum osmolality. The sweat contained 82 ± 16 mmol/L of sodium chloride for an estimated total of 6.8 ± 2.1 g of sodium chloride lost in the sweat. The serum aldosterone increased 3.5-fold from before to after Bikram yoga. There was a decrease in the extracellular body fluid compartment of 9.7%. Sweat loss in Bikram yoga predominately produced a volume depletion rather than the dehydration of body fluids. The sweating-stimulated rise in serum aldosterone levels will lead to increased sodium reabsorption from the kidney tubules and restore the extracellular fluid volume over the next 24 hr.

Calcium loss in sweat does not stimulate PTH release: A study of Bikram hot yoga

It has been hypothesized that sweat loss during exercise causes a disruption in calcium homeostasis that activates bone resorption and over time leads to low bone mineral density. The purpose of this small pilot study was to determine whether dermal calcium loss from a bout of excessive sweating during light intensity physical activity triggers an increase in biomarkers of bone resorption. Biochemical markers related to bone homeostasis were measured before and after a 90 min Bikram hot yoga practice performed in a room heated to 105 °F with 40 % humidity. Participants were five females with a mean age of 47.4 ± 4.7 years. Nude body weight, serum total calcium (Ca²⁺), free ionized calcium, albumin, parathyroid hormone (PTH) and CTX-I were measured before and after a Bikram hot yoga practice. Mean estimated sweat loss was 1.54 ± 0.65 L, which elicited a 1.9 ± 0.9 % decrease in participant's body weight. Mean Ca²⁺ concentration in sweat was 2.9 ± 1.7 mg/dl and the estimated mean total calcium lost was 41.3 ± 16.4 mg. Serum ionized Ca²⁺ increased from 4.76 ± 0.29 mg/dl to 5.35 ± 0.36 mg/dl after the Bikram hot yoga practice (p =  0.0118). Serum PTH decreased from pre- 33.9 ± 3.3 pg/ml to post- 29.9 ± 2.1 pg/ml yoga practice (p =  0.0015) when adjusted for hemoconcentration (PTH_ADJ), implying a decrease in PTH secretion. We conclude that calcium loss in sweat during 90 min of Bikram hot yoga did not trigger an increase in PTH secretion and did not initiate bone resorption.

Effect of 90-Min Bikram Yoga on Basic Psychological Needs Among Practitioners in the Southwestern United States

Background

In our modern society, physical activity is a lifestyle choice. Bikram Yoga is a low impact; moderate exercise and the understanding of motivation and adherence to the practice is unknown. This study aimed to evaluate the effect of 90 min Bikram Yoga practice on basic psychological needs of competence (the sense of skill mastery), autonomy (volitionally performing a task), and relatedness (a connection with others) as postulated in self-determination theory for motivation.

Methods

The sample included Bikram Yoga practitioners in the Southwestern United States (n = 126) averaged between the age group of 35 and 64, predominately female, and highly educated. Responses to the Psychological Need Satisfaction in Exercise Scale were analyzed using multivariate analysis of variance.

Results

Results showed a statistically significant effect of frequency of Yoga attendance on the satisfaction of basic psychological needs (i.e., competence, autonomy, and relatedness); (P = 0.025); specifically, Yoga practitioners who attended four or more classes per week had higher satisfaction levels of Basic Psychological Need for competence (P = 0.013) and relatedness (P = 0.034). A statistically significant effect of the level of experience on the satisfaction of basic psychological needs (i.e., competence, autonomy, and relatedness) (P = 0.014) found in experienced Bikram Yoga practitioners, specifically for competence (P = 0.013) and relatedness (P = 0.023) compared to novice counterparts.

Conclusion

The study provides some evidence of an individual's motivation for a 90 min Bikram Yoga practice and possible adherence. Future investigation of Bikram Yoga practice adopting self-determination theory appears worthwhile.

Upper Airway Thermoregulation During Singing Warm-Up

The primary aim of this research was to quantify the degree to which the upper airway temperature changes with singing warm-up. Based on prior upper airway thermoregulation research it was hypothesized that upper airway temperature would not significantly increase during singing warm up when compared to prewarm up and recovery phases. Ten participants completed a short singing warm-up of their choice until they felt sufficiently warmed up while upper airway temperature was measured at 1 second intervals via a transnasal thermistor placed against the posterior pharyngeal wall, just above the larynx. Descriptive statistics and statistical modeling were used for comparison of pre-warm-up, warm-up, and recovery phases of a short singing warm-up. Results indicated a physiologically-significant increase (≥0.5°C) of upper airway temperature during the singing warm-up when compared to the prewarm up average. Significant differences (P < 0.0001) were identified between all pairwise comparisons analyzed for the three phases of data collected (baseline, warm-up, and recovery). These findings support an upper airway tissue temperature increase in response to the singing warm-up. The extent to which these findings can be generalized to the intrinsic laryngeal muscles is still unknown given the technical difficulty of obtaining intramuscular laryngeal temperature measures.

#MindinBody - feasibility of vigorous exercise (Bikram yoga versus high intensity interval training) to improve persistent pain in women with a history of trauma: a pilot randomized control trial

BACKGROUND

The neurobiology of persistent pain shares common underlying psychobiology with that of traumatic stress. Modern treatments for traumatic stress often involve bottom-up sensorimotor retraining/exposure therapies, where breath, movement, balance and mindfulness, are used to target underlying psychobiology. Vigorous exercise, in particular Bikram yoga, combines many of these sensorimotor/exposure therapeutic features. However, there is very little research investigating the feasibility and efficacy of such treatments for targeting the underlying psychobiology of persistent pain.

METHODS

This study was a randomized controlled trail (RCT) comparing the efficacy of Bikram yoga versus high intensity interval training (HIIT), for improving persistent pain in women aged 20 to 50 years. The participants were 1:1 randomized to attend their assigned intervention, 3 times per week, for 8 weeks. The primary outcome measure was the Brief Pain Inventory (BPI) and further pain related biopsychosocial secondary outcomes, including SF-36 Medical Outcomes and heart rate variability (HRV), were also explored. Data was collected pre (t0) and post (t1) intervention via an online questionnaire and physiological testing.

RESULTS

A total of 34 women were recruited from the community. Analyses using ANCOVA demonstrated no significant difference in BPI (severity plus interference) scores between the Bikram yoga (n = 17) and the HIIT (n = 15). Women in the Bikram yoga group demonstrated significantly improved SF-36 subscale physical functioning: [ANCOVA: F(1, 29) = 6.17, p = .019, partial eta-squared effect size (ηp2) = .175 and mental health: F(1, 29) = 9.09, p = .005, ηp2 = .239; and increased heart rate variability (SDNN): F(1, 29) = 5.12, p = .013, ηp2 = .150, scores compared to the HIIT group. Across both groups, pain was shown to decrease, no injuries were experienced and retention rates were 94% for Bikram yoga and 75% for HIIT .

CONCLUSIONS

Bikram yoga does not appear a superior exercise compared to HIIT for persistent pain. However, imporvements in quality of life measures and indicator of better health were seen in the Bikram yoga group. The outcomes of the present study suggest vigorous exercise interventions in persistent pain cohorts are feasible.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry ( ACTRN12617001507370 , 26/10/2017).

Acute Cardiovascular Responses to a Session of Bikram Yoga: A Pilot Uncontrolled Trial

INTRODUCTION

Main cardiovascular parameters such as heart rate (HR), blood pressure, and myocardial oxygen consumption (MOC) are tightly regulated by a multifactorial, nonlinear control system. Increased HR because of physical activity is often accompanied by an increase in blood pressure. Postural changes have an effect on the baroreceptors, and stretching exercises and isometric contractions modulate muscle mechanoreceptors eliciting increases in blood pressure. However, a hot environment increases the core temperature inducing vasodilation and plasma volume changes that might contribute to a drop in blood pressure. During the practice of Bikram yoga, all these factors converge and little is known about the resulting changes in blood pressure and MOC.

METHODS

Sixteen apparently healthy female volunteers, regular practitioners of Bikram yoga, were evaluated during a 90 min session. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured immediately after each posture and HR was measured continuously during the practice.

RESULTS

HR and estimated MOC increased significantly over baseline during the exercise (+62.3% and +63.6%, respectively). HR mean value across the entire Bikram yoga session was 126.6 ± 14.3 bpm reaching a maximum of 168.1 ± 20.2 bpm. SBP was not significantly increased over baseline at any time during the practice with a mean value of 117.0 ± 10.1 mmHg and DBP was significantly decreased over baseline most of the time (-10.1%, mean 71.2 ± 7.3 mmHg) with particular decline toward the end of the practice during the floor postures.

CONCLUSIONS

DBP during the practice of Bikram yoga was significantly different from that previously reported for nonheated Hatha yoga for normotensive subjects. Further studies evaluating the same group at both conditions are needed to better characterize the magnitude of the changes in HR, SBP, DBP, and MOC.

How does yoga reduce stress? Embodied cognition and emotion highlight the influence of the musculoskeletal system

Yoga is an increasingly popular activity, perhaps because of its association with stress reduction and relaxation - an association that is generally supported by empirical evidence. Understanding of the mediating variables is, however, limited. Given that, the purpose of this paper is to present a theoretical perspective that encourages systematic research regarding the relationship between yoga, stress, and musculoskeletal activity. This embodied perspective parallels popular interest in the mind-body connection and emphasizes the influence of body position on thinking as well as emotion. Those influences take on added meaning in the context of the Cognitive Appraisal Theory and the Biopsychosocial Model of Challenge and Threat. Investigations of embodied cognition suggest that yoga may reduce stress by affecting the way individuals appraise stressors. The combination of body position and common components of yoga practice may also contribute to that effect, particularly when considering thoughts about the self and feelings of confidence. Findings regarding embodied emotion make a similar contribution to understanding the implications of previous research findings and common yoga practices. Considering yoga and stress from an embodied perspective also highlights the role of the musculoskeletal system in the stress process, leading to the question of whether yoga influences stress by directly influencing the musculoskeletal system, indirectly by influencing awareness of that system, or through a combination of the two. Those questions, in turn, highlight the importance of expanding investigations of psychological processes, body position, musculoskeletal activity during yoga, and the interactions between those variables.

Predictors of and barriers to adherence in a 16-week randomised controlled trial of Bikram yoga in stressed and sedentary adults

BACKGROUND

Bikram yoga may enhance health outcomes in healthy adults and those at risk for chronic disease, however, challenges remain in achieving optimal adherence to this practice. This study investigated factors influencing adherence to a 16-week Bikram yoga intervention in stressed and sedentary adults.

METHODS

Experimental group participants (n = 29) were instructed to attend 3-5 Bikram yoga classes weekly for 16 weeks. Baseline demographics, behaviours and health measures were investigated as predictors of adherence. Barriers were assessed via documentation of adverse events, and exit survey responses.

RESULTS

Participants (38.2 ± 10.1 years) were predominantly overweight-obese (83%), female (79%), and attended 27 ± 18 classes. Higher adherence was associated with older age (p = 0.094), less pain (p = 0.011), fewer physical limitations (p = 0.011), poorer blood lipid profile, and higher heart rate variability (HRV; total power, (p = 0.097)). In multi-variable analysis, three variables: age (β = 0.492, p = 0.006), HRV (β = 0.413, p = 0.021) and pain (β = 0.329, p = 0.048) remained predictors of adherence. Difficulty committing to the trial, lack of enjoyment and adverse events were barriers to adherence.

CONCLUSIONS

These findings should be considered in the development of future Bikram yoga trials to facilitate higher levels of adherence, which may enhance health outcomes and inform community practice. Future trials should investigate and address additional barriers and facilitators of Bikram yoga practice.

Leisure Motivation and Satisfaction: A Text Mining of Yoga Centres, Yoga Consumers, and Their Interactions

Understanding the motivation and satisfaction of yoga consumers is of critical importance for both leisure service providers and leisure researchers to enhance the sustainability of personal lives in terms of physical wellness and mental happiness. For this purpose, this study investigated 25,120 pairs of online ratings and reviews from 100 yoga centres in Shanghai, China using latent Dirichlet allocation (LDA)-based text mining, and successfully established the relationship between rating and review. Findings suggest that Chinese yogis are motivated by improving physical condition, improving psychological condition, gracing appearance, establishing social connection, and creating social isolation. In addition to teaching mainstream yoga, yoga centres also provide additional courses. From a consumer perspective, yogis are relatively satisfied with teachers, courses, and the environment, but complain about the supporting staff, membership price, and reservation service. Managerially, yoga centres are encouraged to continue attending to the motivations of yogis, specialising their guidance, and fostering strengths and circumventing weaknesses in their service. This study also contributes by verifying, elaborating on, and tentatively extending the framework of the Physical Activity and Leisure Motivation Scale (PALMS).

Inter-individual differences in weight change following exercise interventions: a systematic review and meta-analysis of randomized controlled trials

Previous reports of substantial inter-individual differences in weight change following an exercise intervention are often based solely on the observed responses in the intervention group. Therefore, we aimed to quantify the magnitude of inter-individual differences in exercise-mediated weight change. We synthesized randomized controlled trials (RCTs) of structured, supervised exercise interventions. Fourteen electronic databases were searched for relevant studies published up to March 2017. Search terms focused on structured training, RCTs and body weight. We then sifted these results for those RCTs (n = 12, 1500 participants) that included relevant comparator group data. Standard deviations (SDs) of weight change were extracted, thereby allowing the SD for true inter-individual differences in weight loss to be calculated for each study. Using a random effects meta-analysis, the pooled SD (95% CI) for true individual responses was 0.8 (-0.9 to 1.4) kg. The 95% prediction interval (based on 2SDs) for true inter-individual responses was -2.8 to 3.6 kg. The probability (% chance) that the true individual response variability would be clinically meaningful (>2.5 kg) in a future study in similar settings was 23% ('unlikely'). Therefore, we conclude that evidence is limited for the notion that there are clinically important individual differences in exercise-mediated weight change.

A preliminary investigation of the effects of one yoga session for service recipients in a behavioral health intensive outpatient program

This was an investigation of the feasibility and effectiveness of a brief yoga intervention (one session) within an intensive outpatient program (IOP) for service recipients diagnosed with various psychiatric disorders. Participants (N = 26) completed the Toronto Mindfulness Scale (TMS) and the Positive and Negative Affect Schedule (PANAS). Data was collected before and after one yoga session and follow-up data was collected via mail after discharge from the IOP. Scores indicated that negative affect significantly decreased and positive affect significantly increased from pre to post yoga session. Mindfulness scores significantly increased from pre to post yoga session. Though the results of this study supported that a yoga intervention is both feasible and effective within an IOP, collection of follow-up data after discharge via mail was not as feasible. The results of this preliminary investigation support a larger and longitudinal study to further examine yoga as a treatment modality with this clinical population.

Routine Yoga Practice Impacts Whole Body Protein Utilization in Healthy Women

Whole body protein utilization (WBPU), which includes flux (Q), protein synthesis (PS), protein breakdown (PB), and whole body protein balance (WBPB), provides insight regarding muscle mass, a criterion for sarcopenia. To characterize yoga's impact on WBPU, body composition and functional measures in healthy (50-65 years) women. WBPU and functional measures were compared between women who routinely practiced yoga (YOGA; n = 7) and nonactive counterparts (CON; n = 8). Q (0.61 ± 0.06 vs. 0.78 ± 0.07, p = .04), PS (3.07 ± 0.37 vs. 4.17 ± 0.40, p = .03), PB (2.59 ± 0.48 vs. 3.80 ± 0.48, p = .05) were lower, and lean body mass higher (64 ± 1 vs. 58 ± 2%, p ≤ .01) for YOGA vs. CON, respectively. WBPB and functional measures were similar. Routine yoga practice influenced WBPU in healthy older women. Study findings are novel and provide a basis for future investigations evaluating long-term benefits of yoga as an alternative mode of exercise for maintaining muscle mass in support of active aging.

Effect of a 16-week Bikram yoga program on heart rate variability and associated cardiovascular disease risk factors in stressed and sedentary adults: A randomized controlled trial

Background

Chronic activation of the stress-response can contribute to cardiovascular disease risk, particularly in sedentary individuals. This study investigated the effect of a Bikram yoga intervention on the high frequency power component of heart rate variability (HRV) and associated cardiovascular disease (CVD) risk factors (i.e. additional domains of HRV, hemodynamic, hematologic, anthropometric and body composition outcome measures) in stressed and sedentary adults.

Methods

Eligible adults were randomized to an experimental group (n = 29) or a no treatment control group (n = 34). Experimental group participants were instructed to attend three to five supervised Bikram yoga classes per week for 16 weeks at local studios. Outcome measures were assessed at baseline (week 0) and completion (week 17).

Results

Sixty-three adults (37.2 ± 10.8 years, 79% women) were included in the intention-to-treat analysis. The experimental group attended 27 ± 18 classes. Analyses of covariance revealed no significant change in the high-frequency component of HRV (p = 0.912, partial η² = 0.000) or in any secondary outcome measure between groups over time. However, regression analyses revealed that higher attendance in the experimental group was associated with significant reductions in diastolic blood pressure (p = 0.039; partial η² = 0.154), body fat percentage (p = 0.001, partial η² = 0.379), fat mass (p = 0.003, partial η² = 0.294) and body mass index (p = 0.05, partial η² = 0.139).

Conclusions

A 16-week Bikram yoga program did not increase the high frequency power component of HRV or any other CVD risk factors investigated. As revealed by post hoc analyses, low adherence likely contributed to the null effects. Future studies are required to address barriers to adherence to better elucidate the dose-response effects of Bikram yoga practice as a medium to lower stress-related CVD risk.

Trial registration

Retrospectively registered with Australia New Zealand Clinical Trials Registry ACTRN12616000867493. Registered 04 July 2016.

The effect of Bikram yoga on endothelial function in young and middle-aged and older adults

The purpose of this investigation was to determine if Bikram yoga, a style of heated hatha yoga, would improve endothelial function in young and middle-aged and older, healthy adults. This trial was performed in 36 young (n = 17) and middle-aged and older adults (n = 19) who completed 3 weekly Bikram yoga classes for 8 weeks. Height, body weight and body composition were determined and endothelial function was measured noninvasively using brachial artery flow-mediated dilation (FMD) before and after the intervention. No changes in body weight, BMI or body fat percentage occurred as a result of the intervention in either group. Brachial artery FMD was significantly increased in middle-aged and older (P < 0.05) but not in young adults as a result of the intervention. The results demonstrate that a relatively short-term Bikram yoga practice might significantly improve vascular endothelial function in middle-aged and older adults. While apparently healthy individuals in this study experienced no adverse events, those with preexisting conditions should take caution and consult with a physician prior to engaging in this style of yoga.

A systematic review and meta-analysis on the effects of yoga on weight-related outcomes

INTRODUCTION

Overweight and obesity are among the most important modifiable risk factors for chronic diseases and premature death. The aim of this review was to systematically assess and analyze the effects of yoga on weight-related outcomes.

METHODS

Medline/PubMed, Scopus, and the Cochrane Library were screened through March 2015 for randomized controlled trials on yoga for weight-related outcomes in the general population or overweight/obese individuals. Risk of bias was assessed using the Cochrane risk of bias tool on the following domains: selection bias, performance bias, detection bias, attrition bias, reporting bias, and other bias.

RESULTS

Out of 445 records identified during literature search, 30 trials with a total of 2173 participants were included. No effects on weight, body mass index, body fat percentage or waist circumference were found. In studies with healthy adult participants an effect of yoga compared to usual care was found regarding waist/hip ratio (SMD=--1.00; 95% CI=--1.44, -0.55; p<0.001). In studies with overweight/obese participants only, effects relative to usual care were found for body mass index (SMD=-0.99; 95% CI=-1.67, -0.31; p=0.004). Effects however were not robust against selection bias; and publication bias could not be ruled out. No intervention-related adverse events were reported.

CONCLUSIONS

Despite methodological drawbacks, yoga can be preliminarily considered a safe and effective intervention to reduce body mass index in overweight or obese individuals.

Yoga Training in Junior Primary School-Aged Children Has an Impact on Physical Self-Perceptions and Problem-Related Behavior

The present pilot study investigated the effects of yoga training, as compared to physical skill training, on motor and executive function, physical self-concept, and anxiety-related behavior in junior primary school-aged children. Twenty-four participants with a mean age of 8.4 (±1.4) years completed either yoga or physical skill training twice a week for 6 weeks outside of regular school class time. Both forms of training were delivered in an individualized and child-oriented manner. The type of training did not result in any significant differences in movement and executive function outcomes. In terms of physical self-concept, significant group differences were revealed only for perceived movement speed such that yoga training resulted in perceptions of being slower while physical skill training resulted in perceptions of moving faster. Analysis of anxiety related outcomes revealed significant group effects only for avoidance behavior and coping strategies. Avoidance behavior increased following yoga training, but decreased following physical skill training. In addition, following yoga training, children showed an increased use of divergent coping strategies when facing problematic situations while after physical skill training children demonstrated a decrease in use of divergent coping strategies. Changes in overall physical self-concept scores were not significantly correlated with changes in avoidance behavior following yoga training. In contrast, following physical skill training increased physical self-concept was significantly correlated with decreases in avoidance behavior. In sum, exposure to yoga or physical skill training appears to result in distinct effects for specific domains of physical self-concept and anxiety-related behavior. Further studies with larger samples and more rigorous methodologies are required to further investigate the effects reported here. With respect to future studies, we address potential research questions and specific features associated with the investigation of the effects of yoga in a sample of school-aged children.

The Effects of Bikram Yoga on Health: Critical Review and Clinical Trial Recommendations

Bikram yoga is a style of hatha yoga involving a standarized series of asanas performed to an instructional dialogue in a heated environment (40.6°C, 40% humidity). Several studies evaluating the effect of Bikram yoga on health-related outcomes have been published over the past decade. However, to date, there are no comprehensive reviews of this research and there remains a lack of large-scale, robustly-designed randomised controlled trials (RCT) of Bikram yoga training. The purpose of this review is to contextualise and summarise trials that have evaluated the effects of Bikram yoga on health and to provide recommendations for future research. According to published literature, Bikram yoga has been shown to improve lower body strength, lower and upper body range of motion, and balance in healthy adults. Non-RCTs report that Bikram yoga may, in some populations, improve glucose tolerance, bone mineral density, blood lipid profile, arterial stiffness, mindfulness, and perceived stress. There is vast potential for further, improved research into the effects of Bikram yoga, particularly in unhealthy populations, to better understand intervention-related adaptations and their influence on the progression of chronic disease. Future research should adhere to CONSORT guidelines for better design and reporting to improve research quality in this field.

Effects of Modified Hatha Yoga in Industrial Rehabilitation on Physical Fitness and Stress of Injured Workers

PURPOSE

The purpose of this study was to assess the effects of 8 weeks of modified hatha yoga training on physical fitness and stress level in injured workers.

METHODS

Eighteen male and female injured workers, age between 18 and 55 years, participated in this study. They were divided into two groups: an additive hatha yoga training to routine industrial rehabilitation program group (HYG: n = 9) and a control group with no yoga training (CG: n = 9). A modified hatha yoga protocol was designed for this population by two certified yoga instructors, approved by a physical therapist, and conducted for 1 h, three times weekly for 8 weeks. Physical fitness variables including flexibility of lower back and hamstrings, hand grip strength and lung capacity and scores of sensitivity to stress were evaluated at the time of recruitment and after 8 weeks of intervention.

RESULTS

The values of all physical fitness variables and stress scores were no significant difference between the two groups at baseline. Significant post-yoga improvements for HYG group were noted in flexibility, hand grip strength, and vital capacity (p < 0.05). In contrast, there was no significant change in the CG group. Stress scores did not change as a result of hatha yoga training.

CONCLUSION

An 8-week modified hatha yoga training experience exerted therapeutic effects on physical fitness variables including flexibility of lower back and hamstrings, hand grip strength and vital capacity, but not on stress level in injured workers. These findings indicate that hatha yoga can be a beneficial adjunct to routine physical therapy treatment in industrial rehabilitation programs.

Yoga, bioenergetics and eating behaviors: A conceptual review

Yoga is an ancient oriental discipline that emerged from mystical and philosophical concepts. Today it is practiced in the west, partly due to the promotion of its benefits to improve the lifestyle and overall health. As compared to non-Hatha Yoga (HY) practitioners, healthier and better-eating patterns have been observed in those who practice it. Agreement with the brought benefits, HY can be used as a therapeutic method to correct abnormal eating behaviors (AEB), obesity, and some metabolic diseases. However, the energy expenditure during traditional protocols of HY is not high; hence, it is not very effective for reducing or maintaining body weight or to improve cardiovascular conditioning. Even so, several observational studies suggest significant changes in eating behaviors, like a reduction in dietary fat intake and increments in that of fresh vegetables, whole grains and soy-based products, which in turn may reduce the risk for cardiovascular diseases. Given the inconsistency of the results derived from cross-sectional studies, more case–control studies are needed to demonstrate the efficacy of HY as an alternative method in the clinical treatment of disordered eating and metabolic diseases.

Influences of a yoga intervention on the postural skills of the Italian short track speed skating team

Introduction

In preparation for a short track speed skating season, eight men and seven women were given yoga sessions during an 8-week high volume training cycle. The sessions were planned according to the postural aspects specific to short track speed skating technical requirements. Three specific goals were selected for the intervention: 1) to observe whether the practice of yoga as postural training could improve the efficiency and the athlete’s repertoire along the muscular synergies solicited in the short track speed skating specific technique; 2) to enhance and diversify the motor time-on-task of athletes without changing the prescription of other training stimulus; and 3) to lower the risk of injury during periods with high volumes of training.

Methods

A total of 36 sessions of yoga were given. Three postural tests were administered before and after the intervention with 14 angles analyzed. Non-parametric Wilcoxon test was used to compare angles’ variations.

Results

The 36 yoga sessions totalized 986 minutes of motor time-on-task, registering a proportion of 30% of the global motor time-on-task of the training cycle. Improvements were found in eleven of the 14 angles measured when comparing pre- and post-postural tests (P-value from 0.01 to 0.005). During the 8 weeks, excepting traumatic injuries due to short track speed skating accidents, no skaters suffered injuries linked to the high volume of training. Following the intervention, coaches noticed, following their on-ice feedbacks, an adjustment in the efficiency of the skating technique, in particular regarding hip dissociation.

Conclusion

These results suggest that yoga could be inserted into out-of-season training cycles, even in a high volume training cycle. Planned with the decision training tools, it allows athletes to diversify their motor time-on-task by integrating a new functional range of generic movements with the solicitation of neuromuscular synergies related to the specificity of their sport.

Characteristics of randomized controlled trials of yoga: a bibliometric analysis

Background

A growing number of randomized controlled trials (RCTs) have investigated the therapeutic value of yoga interventions. This bibliometric analysis aimed to provide a comprehensive review of the characteristics of the totality of available randomized yoga trials.

Methods

All RCTs of yoga were eligible. Medline/PubMed, Scopus, the Cochrane Library, IndMED, and the tables of content of yoga specialty journals not listed in medical databases were screened through February 2014. Bibliometric data, data on participants, and intervention were extracted and analyzed descriptively.

Results

Published between 1975 and 2014, a total of 366 papers were included, reporting 312 RCTs from 23 different countries with 22,548 participants. The median study sample size was 59 (range 8–410, interquartile range = 31, 93). Two hundred sixty-four RCTs (84.6%) were conducted with adults, 105 (33.7%) with older adults and 31 (9.9%) with children. Eighty-four RCTs (26.9%) were conducted with healthy participants. Other trials enrolled patients with one of 63 varied medical conditions; the most common being breast cancer (17 RCTs, 5.4%), depression (14 RCTs, 4.5%), asthma (14 RCTs, 4.5%) and type 2 diabetes mellitus (13 RCTs, 4.2%). Whilst 119 RCTs (38.1%) did not define the style of yoga used, 35 RCTs (11.2%) used Hatha yoga and 30 RCTs (9.6%) yoga breathing. The remaining 128 RCTs (41.0%) used 46 varied yoga styles, with a median intervention length of 9 weeks (range 1 day to 1 year; interquartile range = 5, 12). Two hundred and forty-four RCTs (78.2%) used yoga postures, 232 RCTs (74.4%) used breath control, 153 RCTs (49.0%) used meditation and 32 RCTs (10.3%) used philosophy lectures. One hundred and seventy-four RCTs (55.6%) compared yoga with no specific treatment; 21 varied control interventions were used in the remaining RCTs.

Conclusions

This bibliometric analysis presents the most complete up-to-date overview on published randomized yoga trials. While the available research evidence is sparse for most conditions, there was a marked increase in published RCTs in recent years.

Electronic supplementary material

The online version of this article (doi:10.1186/1472-6882-14-328) contains supplementary material, which is available to authorized users.

Oxygen Consumption Changes With Yoga Practices

Oxygen consumption varies with physical and mental activity as well as pathological conditions. Although there is a strong relationship between yoga and metabolic parameters, the relationship between yoga and oxygen consumption has not yet been formally reviewed. This systematic review attempted to include all studies of yoga that also measured oxygen consumption or metabolic rate as an outcome. A total of 58 studies were located involving between 1 and 104 subjects (average 21). The studies were generally of poor methodological quality and demonstrated great heterogeneity with different experimental designs, yoga practices, time periods, and small sample sizes. Studies report yoga practices to have profound metabolic effects producing both increase and decrease in oxygen consumption, ranging from 383% increase with cobra pose to 40% decrease with meditation. Compared to nonpractitioners, basal oxygen consumption is reported to be up to 15% less in regular yoga practitioners, and regular yoga practice is reported to have a training effect with oxygen consumption during submaximal exercise decreasing by 36% after 3 months. Yoga breathing practices emphasize breathing patterns and retention ratios as well as unilateral nostril breathing, and these factors appear critical in influencing oxygen consumption. A number of studies report extraordinary volitional control over metabolism in advanced yoga practitioners who appear to be able to survive extended periods in airtight pits and to exceed the limits of normal human endurance. More rigorous research with standardized practices is required to determine the mechanisms of yoga’s metabolic effects and the relevance of yoga practices in different clinical populations.