What is Yoga?
Yoga has boomed in popularity in Western culture in the last few decades and is often associated with a certain demographic group within that culture (i.e., rich White women). However, yoga is a practice that has existed for somewhere between 2,000 and 5,000 years and can be beneficial for a wide range of people.
Yoga developed in ancient India and is meant to harmonize the mind, body, and spirit through breathing exercises, yoga poses (called asanas), and meditation. In Western culture, lots of people practice yoga without the spiritual component and instead focus on harmonizing the mind and body. Naturally this means yoga is a great fit for this series looking at mind-body connections. You often hear people talking about the benefits of yoga, which made me curious what the research says about yoga.
Another post in this series is going to focus on the benefits of exercise, so I was reluctant to make an entire post for yoga. However, after looking at some of the research, it does appear that yoga has enough differences from general exercise that make it worth exploring on its own.
Research has found good outcomes for yoga using a variety of different populations, suggesting yoga can be helpful for a variety of problems including coping with stress, recovering from or managing a disease or illness such as cancer, chronic pain, or schizophrenia.
There is actually a lot of research out there, so the research presented is really just a snippet of what yoga can potentially offer. The interesting thing about yoga is that it appears to impact the body in many different positive ways. This post is going to focus on how yoga can help people cope with stress
Yoga Improves Mental Health, Cognitive Functioning, and Cellular Activity
There are many different reasons why people experience stress, sometimes we pressure ourselves to do more than is realistic, sometimes there are external pressures that feel stressful. Regardless of the reason, science clearly shows that stress is harmful physically and mentally and so good interventions for stress are needed.
One job that we can probably all agree on that is stressful, is being a caregiver for someone else. Being a caregiver is both emotionally and physically draining work, especially when working with someone who has a chronic or terminal illness.
Some researchers conducted a study with family caregivers who were caring for an individual with dementia . The researchers put the caregivers into either a Kirtan Kirya yogic meditation group or a relaxation group where the caregivers listened to relaxing music. Both the yogic meditation and the relaxing music were for 12 minutes per day for 8 weeks.
What the researchers found was that at the end of the study, the yogic meditation group had lower levels of depression, better overall mental health, and even better cognitive functioning. On their own, these are great findings. However, the researchers found an even cooler finding by looking at something called telomeres.
A telomere is a DNA sequence found at the end of chromosomes that help make sure that the entire chromosome is copied during DNA replication. Without telomeres, the chromosomes start to become shorter and shorter over time, which naturally has negative consequences if the chromosome has important functions. While telomeres naturally shorten over time after DNA replication, it is also possible to reverse this shortening with something called telomerase.
Previous research has shown that telomere shortening naturally occurs with age and that stress can prematurely shorten these telomeres. Why do we care about telomeres? Because shortened telomeres and reduced telomerase are related to premature death and other health risks and diseases including cancer and heart disease.
Getting back to the previously mentioned study, the researchers found that the yogic meditation group had 43% improvement in telomerase compared to 3.7% in the relaxation group. This is really cool because it indicates that meditation can actually help reduce stress-related cellular aging. So not only does yogic meditation help us feel better, it is actually changing our bodies at a cellular level! While more research needs to be done in this area, this study is great example of how physical factors and mental health factors are interrelated.
Yoga and Inflammation
An interesting study by Kiecolt-Glaser and colleagues  looked at how yoga might be related to stress-reduction by examining inflammation and endocrine markers in yoga practicers. Inflammation is important to examine because it is a significant predictor of death in older adults and has been linked to cancer. Factors such as obesity, physical activity, depression, anxiety, and stress have all been shown to impact inflammation and the related ‘proinflammatory cytokines,’ which are molecules that regulate inflammation amongst other things. Proinflammatory cytokines have been associated with a variety of problems including Alzheimer’s disease, cardiovascular disease, type II diabetes, arthritis, and osteoporosis.
Going back to the study, the researchers exposed 25 yoga novices and 25 yoga experts to three conditions: a hatha yoga session, a movement control (walking on a treadmill), and a passive-video control (where participants watched a movie about physics).
What the researchers found was that, contrary to their expectations, there were no changes in inflammatory or endocrine responses after a yoga session for participants. However, there were significant differences found between yoga experts and novices more generally.
Importantly, yoga experts had a reduced number of proinflammatory cytokines compared to novices and produced fewer of these cytokines in reaction to a stressor compared to novices. Thus yoga experts were having different physiological responses to a stressful event compared to yoga experts. It appears that practicing yoga can help reduce inflammation below levels than would be expected by factors such as age, depression, fitness level, and body fat percentage. As such, there appears to be support for regularly practicing yoga as a way to help reduce inflammation
Yoga and Hypertension
Inflammation can be one response to stress, but hypertension is another common problem facing an estimated 76 million Americans. When untreated, hypertension can lead to heart attacks, strokes, and aneurysms, amongst other problems. Yoga is believed to be one type of intervention that can improve blood pressure control and thus help treat hypertension.
A review and meta-analysis (where authors run statistics on a group of studies) of the impact of yoga on hypertension found 17 studies from 1966 to 2013 . The authors found that yoga had a moderate effect on both systolic and diastolic blood pressure. In addition, the authors found that yoga interventions were effective when they included three basic parts of yoga (postures, meditation, and breathing), but not when more limited interventions were given. In addition, for this meta-analysis, yoga was more effective compared to no treatment, but was not more effective than exercise.
Unfortunately, each of the studies used in this meta-analysis was determined to have an unclear or high risk of bias. Therefore, at this time while yoga appears promising as an intervention for hypertension, additional research is needed with rigorous controlled trials.
That being said, the researchers noted that the impact of yoga on blood pressure reduction was similar to the impact of exercise, and reducing intake of sodium and alcohol, which are quite the impressive comparisons
Yoga and Workplace Stress
A British study looking at the impact of yoga on workplace stress randomly placed 48 employees into either a six-week Dru Yoga group or a waitlist control group . Dru Yoga is a type of yoga that consists of different movements, postures, directed breathing exercises, and relaxation techniques and is considered a safe and accessible form of yoga that most people can engage in.
This study found that after the yoga intervention, employees rated themselves as feeling more clear-minded, composed, energized, and confident compared to the waitlist group. In addition, the yoga intervention group reported increased life purpose and satisfaction, as well as more self-confidence in stressful situations compared to the waitlist group.
Overall, this study found that a relatively short intervention of six sessions of yoga was helpful in improving employee well-being and perceived ability to deal with stress.
Yoga Versus Exercise
As previously mentioned, there was some hesitation on my part to dedicate a post to yoga given that another post will be dedicated to physical exercise. However, there are important differences between yoga and general physical exercise, including that yoga often includes meditation and breathing exercises that are not found with physical exercise.
A review of the literature directly compared the benefits of yoga and exercise on many different health outcome measures and health conditions . The researchers found that yoga was almost always as beneficial or more beneficial than exercise on these health outcomes, with the exception of outcomes that involved physical fitness.
Specifically, exercise did better in terms of outcomes such as calories expended, heart rate, and oxygen consumption. In contrast, yoga did better in terms of outcomes such as stress response, flexibility, fatigue, balance, quality of life, and pain reduction.
As noted in the review, yoga appears to work by turning down the hypothalamic-pituitary-adrenal (HPA) axis, which controls reactions to stress (amongst other functions), and the sympathetic nervous system, which is largely responsible for our ‘fight-or-flight’ responses.
The HPA axis and the sympathetic nervous system are both impacted by stress and are related to disease and disability through many different processes, including inflammation, increased blood pressure, increased cortisol, and increased blood glucose levels. Yoga is theorized to help prevent disease and disability due to stress in part by helping to control these processes mentioned.
It appears that both yoga is often as good as, or slightly better, than general physical exercise for many different health outcomes. More good quality research is of course needed to further determine similarities/differences between yoga and exercise, including what are the essential components of yoga and how the intensity of the yoga practice is related to these health outcomes.
In summary, yoga has been associated with many positive outcomes that affect physical and mental well-being, many of which are related to stress. While there appears to be a consistent theme with yoga research for more unbiased, rigorously controlled studies, at present yoga does appear to have a benefit as an added component to other treatments.
Whether yoga can completely replace other types of intervention (e.g., physical exercise) still remains to be determined, but there appears to be promise that this is the case. This would mean that individuals could have greater choice in determining treatment.
For full disclosure, I was suspicious of yoga for a long time. I never doubted that it could be helpful, but it never seemed like it could provide the physical exercise that I felt I needed during a workout. I will say that resistance has been slowly chipped away, both by reading the research and practicing some yoga informally.
I am still a complete novice at yoga, but I have found that you can definitely work your muscles during yoga depending on the poses used. In addition, I enjoy the meditation or mindfulness components of yoga that help reduce stress and help me focus on the present moment.
Who knows if I will ever be a yoga expert, but after delving into the research on yoga, I am definitely more motivated to be open-minded about it and finding ways to incorporate more yoga into my exercise routines.
Hopefully you too learned something new about yoga. One thing is for certain, yoga has been around for thousands of years and is not going away anytime soon. It is practiced by people young and old, who have a variety of different skill levels. Hopefully increased research and attention towards yoga will help make it affordable for individuals of all backgrounds to participate in.
If you have not given yoga a try before, maybe check it out, especially if you feel like you are dealing with a lot of stress in your life (and let us be honest, who is not dealing with stress?). Who knows, it may just click for you - worst case, you can check out what all the fuss is about. And remember, there are a lot of different types of yoga, so there is likely a type that will suit you well. Keep an open mind and you may be on your way to a happier, healthier future!
The Clinically Relevant Insights Blog, part of ShawnWilsonPhD.com, shares news and research related to psychology and wellness.
 Lavretsky, H., Epel, E., Siddarth, P., Nazarian, N., Cyr, N. S., Khalsa, D., . . . Irwin, M. (2013). A pilot study of yogic meditation for family dementia caregivers with depressive symptoms: Effects on mental health, cognition, and telomerase activity. International Journal of Geriatric Psychiatry, 28(1), 57-65. doi:10.1002/gps.3790
 Kiecolt-Glaser, J. K., Christian, L., Preston, H., Houts, C. R., Malarkey, W. B., Emery, C. F., & Glaser, R. (2010). Stress, Inflammation, and Yoga Practice. Psychosomatic Medicine, 72(2), 113-121. doi:10.1097/psy.0b013e3181cb9377
 Hagins, M., States, R., Selfe, T., & Innes, K. (2013). Effectiveness of Yoga for Hypertension: Systematic Review and Meta-Analysis. Evidence-Based Complementary and Alternative Medicine, 2013, 1-13. doi:10.1155/2013/649836
 Hartfiel, N., Havenhand, J., Khalsa, S. B., Clarke, G., & Krayer, A. (2010). The effectiveness of yoga for the improvement of well-being and resilience to stress in the workplace. Scandinavian Journal of Work, Environment & Health, 37(1), 70-76. doi:10.5271/sjweh.2916
 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. doi:10.1089/acm.2009.0044