Several controversies about yoga as a healthy lifestyle are reported, and the most common criticism against yoga focuses on yoga-related injury rates and poor methodological protocols used in studies that prove its health benefits. While injuries cannot be used as a critique against yoga because engaging in any physical activity carries a risk of injury, it is possible to notice that some sources of information are not reliable when it comes to evaluating the health benefits of yoga.
According to a survey in Australia, 78.7 percent of the 2353 respondents claimed they had never experienced injury while practicing yoga while 21.3 percent reported they had experienced injuries during practice (Penman, Cohen, Stevens, & Jackson, 2012). However, when only significant injuries are taken in account, 10.4 percent of the respondents experienced severe injuries, which resulted in time off work, prolonged pain, or medical treatments (Penman et al., 2012).
It is not possible to consider yoga directly responsible for those injuries because most respondents took personal responsibility for forcing positions, skipping warm-up, and being egoistic (Penman et al., 2012). Of course, the possibility of bias is high because practitioners could take the blame to protect their lifestyle choice. Nevertheless, the injuries most likely occurred because of poor preparation or inadequate experience because they are reported only in difficult positions that should be exercised with caution, such as shoulder stands, headstands, lotus, and handstands (Penman et al., 2012). Exertion and fatigue can also play a role in injuries that occur during forward and backward bends because the muscles protecting the lumbar area can fail and cause back injuries. As long as practitioners know their limits, have realistic expectations, and practice yoga responsibly, they will avoid physical injuries.
Reliability of Studies on Yoga Health Benefits
Ospina et al. (2008) evaluated the quality of methodological approaches in studies concerned with spiritual and healing practices, such as meditation and yoga, to prove the validity of their findings. Several results suggested poor methodological quality. For example, it was found that only 49 percent of the randomized controlled trials reported withdrawals and drop-outs while only 11 percent of them provided a complete description of the randomization process (Ospina et al., 2008).
Other systematic reviews on yoga studies show similar findings. Several studies found that yoga is effective in reducing anxiety and related disorders, but the reviewers found poor design quality in most studies, so it was not possible to generalize the findings (as cited in Ospina et al., 2008). Furthermore, while randomized controlled trials on the benefits of yoga for reducing depression were all positive, they failed to report various design details, such as randomization method or compliance rates, which undermines their validity (as cited in Ospina et al., 2008). In terms of psychological health, the most comprehensive and reliable studies aimed to investigate the effects of yoga practice on patients with obsessive-compulsive disorder (OCD), and their results support the effectiveness of yoga in reducing symptoms observed in OCD patients (as cited in Ospina et al., 2008).
Although the study by Ospina et al. (2008) did not include yoga-related research from Indian journals, cultural bias may also play a significant role in determining researcher bias. For example, the study by Ankad, Herur, Patil, Shashikala, and Chinagudi (2011) found that pranayama and meditation significantly decreases resting pulse rate, mean arterial blood pressure, diastolic blood pressure, and systolic blood pressure, but the researchers failed to discuss limitations and had implemented a poor design, so the research results cannot be compared to other studies or reproduced effectively.
The study by Ankad et al. (2011) had several fallacies. First, it is not possible to generalize the findings because of the small sample size. With only 50 healthy participants between 20 and 60 years of age, the sample size is insignificant because it is not possible to generalize the finding accurately on the entire population, which would mean all healthy individuals between the ages of 20 and 60. Second, the study states that t-tests were used to determine statistical significance. However, the researchers do not report using multiple comparison tests required for this type of study, so the P values, which are all displayed as statistically significant at P < .001, could be inaccurate.
With a poor statistical design, which failed to implement proper significance tests and establish a linear correlation between the dependent variables and independent variables, it is possible to consider that the levels of bias among the researchers were high. However, this one example does not prove that all researchers who consider yoga their cultural heritage are biased, but it does point out that possibility and suggests studies need to be analyzed carefully before making conclusions.
Although the criticism on researcher bias and methodological designs is valid, it is possible to notice a significant improvement in the quality of studies that aim to clarify the health benefits of yoga and its impact on physiological systems. With the advancement in medical science, it is also possible to investigate the impact of yoga practice on brain patterns and neuroendocrinal mechanisms that are responsible for regulating hormones associated with stress and the development of psychological disorders (Ross & Thomas, 2010).
Furthermore, research designs in studies aimed at contemporary and alternative medicine have been improving over the past decades. According to systematic reviews, the results obtained through methodologically correct studies support the hypotheses on the effectiveness and safety of alternative practices (as cited in Ospina et al., 2008). While future research is needed to create large and reproducible studies that can be used to support the health benefits of yoga, the literature that is currently available indicates that yoga is a healthy lifestyle practice that improves physical and psychological health.
Vegetarianism among Yoga Practitioners
Most yoga practitioners who embrace the lifestyle also adopt vegetarianism, which has been an important principle of yoga since its development. Although the American Dietetic Associated approves vegetarianism as a healthy lifestyle (Craig & Mangels, 2009), being a vegetarian is associated with several risks. Vegetarians are at a higher risk for developing vitamin deficiencies and mineral deficiencies (Byrnes, 2000). Because the vegetarian diet is mainly based on carbohydrates and low on fat and protein, they are also at risk for developing both physical and psychological problems (Byrnes, 2000). It is not possible to ignore those risks, but it is possible to significantly reduce them significantly and create a healthy diet while maintaining the desired lifestyle.
For example, protein deficiencies are common in vegetarians because animal products are the only complete sources of protein. That means eating animal products provides the body with all essential amino acids it needs to function properly while plant-based foods are incomplete sources of protein, so it is not possible to obtain all essential amino acids from a single source. That problem can be resolved by combining several complementary plant-based foods. For example, both rice and beans are incomplete sources of protein, but when they are combined, the body obtains all required amino acids (Columbia University, 2008). Vitamin and mineral deficiencies can be avoided through several strategies, such as supplementation or avoiding non-fermented and hyper-processed soy beans (Byrnes, 2000). With proper knowledge and planning, the vegetarian diet can be designed to provide all required nutrients.
In a review of comparison studies by Ross and Thomas (2010), the focus was on randomized controlled trials that compared the effects of yoga to other forms of exercise, such as aerobic activities or stretching. In all instances, yoga was superior to other types of activities in terms of alleviating symptoms associated with hormonal imbalances during menopause and mental disorders (Ross & Thomas, 2010). The participants in groups who engaged in yoga practice also reported lower stress levels on the Perceived Stress Scale (PSS) and higher results in quality of life when assessed by the World Health Organization Quality of Life BREF form (as cited in Ross & Thomas, 2010). Both questionnaires have been tested and approved for use as valid and reliable self-assessment tools.
The practice of yoga is not restricted to physically healthy individuals. A randomized controlled trial by Kyizom, S. Singh, K. P. Singh, Tandon, and Kumar (2010), on 60 type-2 diabetes patients found that using yoga asanas and pranayama in addition to conventional therapy shows significant improvement in cognitive functions of the brain. According to the self-reported assessments, patients who practiced yoga also reported increased physical and emotional well-being, alertness, and happiness (Kyizom et al., 2010).
Overall, yoga shows significant improvements in mood and psychological functioning in all practitioners, regardless of their age, sex, or current conditions. A study on women in Germany showed that the participants who attended a 90-minute classes once per week for three months showed a 50 percent improvement in depression scores, 30 percent improvement in anxiety scores, and 65 percent improvement in overall well-being scores (as cited in Sengupta, 2012).
While most studies on the effects of yoga on emotional well-being are concerned with healthy individuals, a study at the New Hampshire psychiatric hospital investigated the effects of one yoga class on 113 patients. Psychological tension, hostility towards staff, anxiety, depression, and anger were significantly reduced immediately after the class (as cited in Sengupta, 2012). Finally, the improvements in mood and quality of life after practicing yoga were recorded in elderly patients, healthcare providers who provide end-of-life care, and survivors of progressive diseases, such as breast cancer or heart disease patients (as cited in Sengupta, 2012).
Of course, while yoga is associated with improved health, it is important to recognize that like many alternative healing practices, yoga has certain limitations in application. In all instances of chronic disorders, yoga does not completely remove the causes, but it only helps practitioners regulate the symptoms and improve the practitioner’s attitude and mental state.
For example, cancer patients reported experiencing reduced anxiety regarding treatment outcomes, which resulted in a better quality of life (as cited in Sengupta, 2012). While yoga can improve their quality of life and their chances of achieving better clinical outcomes (as cited in Sengupta, 2012), it is not effective against cancer without conventional treatments. Although yoga has several benefits, the practitioners’ responsibilities include knowing its limitations and respecting the importance of conventional treatments when managing and treating disorders.
It is possible to notice that adopting yoga as a lifestyle is beneficial to practitioners. When practitioners understand their limitations and practice within the boundaries of their physical and psychological abilities, they can improve physiological functions, achieve better hormonal balance, improve their sense of well-being, and improve their quality of life.
Although yoga practice is associated with improved physical and psychological health, it is still not clear how pranayama or asanas impact physiological mechanisms associated with those results. Kyizom et al. (2010) indicate that practicing yoga can lead to alterations in neuroendocrinal mechanisms, which would explain the reductions in oxidative stress that can reduce cognitive abilities.
Certain yoga asanas and pranayama may contribute to the down-regulation of the sympathetic nervous system and the hypothalamic-pituitary-adrenal axis, which are triggered and stimulated by external stressors and can cause a variety of physical and psychological issues when unregulated (Ross & Thomas, 2010). Future research needs to address those mechanisms to improve targeted implementations of yoga as a supplement to conventional treatments. For example, there are currently no classifications of specific yoga forms, postures, and pranayama in terms of risks when applied to specific groups and in terms of strategic application of certain forms and postures when treating patients with specific disorders.
While all studies report significant psychological benefits, even in hospitalized patients, it is important to consider the practitioners’ medical history because certain forms that require higher humidity and temperature may be contradictory to patients with asthma (Ross & Thomas, 2010). Longitudinal studies are also needed on the effects of yoga on psychiatric patients to measure relapse rates, compliance rates, and determine whether longer practice time is associated with adverse events.
Although the academic community requires more evidence and reproducible results from larger studies to acknowledge the health benefits of yoga, it is evident that the yoga lifestyle has several benefits when implemented correctly. Yoga is a healthy lifestyle that can improve physical health, psychological health, and help individuals manage their moods and existing chronic disorders. Taking in account risks associated with physical injuries from asanas or possible side-effects of vegetarianism is required to implement proper solutions that allow individuals to reduce risks and increase the benefits of their lifestyle choice.
Ankad, R. B., Herur, A., Patil, S., Shashikala, G. V., & Chinagudi, S. (2011). Effect of short-term pranayama and meditation on cardiovascular functions in healthy individuals. Heart Views: The Official Journal of the Gulf Heart Association, 12(2), 58-62.
Byrnes, S. (2000) The Myths of Vegetarianism. Townsend Letter for Doctors and Patients, 72-81.
Columbia University. (2008). Very low protein diet – Good for health? Retrieved from http://goaskalice.columbia.edu/very-low-protein-diet-151-good-health
Craig, W. J., & Mangels, A. R. (2009). Position of the American Dietetic Association: Vegetarian diets. Journal of the American Dietetic Association 109(7), 1266-1282.
Kyizom, T., Singh, S., Singh, K. P., Tandon, O. P., & Kumar, R. (2010). Effect of pranayama & yoga-asana on cognitive brain functions in type 2 diabetes-P3 event related evoked potential (ERP). Indian Journal of Medical Research, 131(5), 636-640.
Ospina, M. B., Bond, K., Karkhaneh, M., Buscemi, N., Dryden, D. M., Barnes, V., & Shannahoff-Khalsa, D. (2008). Clinical trials of meditation practices in health care: characteristics and quality. The Journal of Alternative and Complementary Medicine, 14(10), 1199-1213.
Penman, S., Cohen, M., Stevens, P., & Jackson, S. (2012). Yoga in Australia: Results of a national survey. International Journal of Yoga, 5(2), 92-101.
Ross, A., & Thomas, S. (2010). The health benefits of yoga and exercise: a review of comparison studies. The Journal of Alternative and Complementary Medicine, 16(1), 3-12.
Sengupta, P. (2012). Health impacts of yoga and pranayama: A state-of-the-art review. International Journal of Preventive Medicine, 3(7), 444-458.