The New Science of the Health Benefits of Yoga

The health benefits of yoga have been long known, but can it replace areas of modern medicine? Kerry Sullivan takes a look at the latest hard science...

Chances are you or someone you know practices yoga. It has become a wildly popular, billion-dollar industry. Yet if you ask ‘What is yoga?’ you’re bound to get all sorts of answers.

A rookie response usually goes something like this: ‘Yoga is that thing you do on a mat with a bunch of stretching and breathing.’ Simple, yes, but also quite correct — in a manner of speaking.

One of the most amazing things about the ancient tradition of yoga is that it can be interpreted in so many different ways. For some people, yoga is a tool to become physically fit; for others, it is a religion. If practiced in full, yoga can satisfy the physical, mental, emotional, and spiritual needs of a person.

Indeed, a great deal of research has been conducted over the past few years to find out if yoga can serve as a bona fide alternative to certain modern medical practices. Science has finally decided to give this ancient art the empirical treatment.

A Brief History of Yoga

Yoga is a discipline that combines various physical postures and breathing techniques, as well as meditation and philosophy.

It was created over 2,000 years ago in India and started to gain popularity in the West in the early 20th century, thanks in large part to two emissaries, Swami Vivekanada and Paramahansa Yogananda, who were determined to have its effects known and practiced in the Americas.

Today, most Western yoga facilities focus mainly on the physical dimension of yoga, though yoga in its entirety remains an all-encompassing manner of living.

There are many different styles of yoga such as Astanga, Hatha, Karma, and Bhakti, just to name a few. Although some positions are positively impossible-looking, for the most part, yoga is the repetition of a series of simple postures achievable by just about anyone.

The Problem These Days

In this day and age, life moves pretty fast. With the rise of smartphone technology, people are now constantly on-call, for business or for pleasure. Despite the many conveniences this type of living affords us, time remains scarce — there is little to no time to maintain your health; it is far more time efficient to take a pill when you can’t sleep or want to lose weight or are in pain or in distress. 

By contrast, yoga is not easy or fast. It takes weeks of dedicated practice to see results. No one can administer yoga to you; there are no shortcuts to the practice. Even the best teacher in the world can only open the door — it’s up to you to walk through it.

There is a growing body of scientific evidence — as well as infinite fables, parables, and proverbs — that suggest the quick, easy route is not the best. Recent research has shown that an investment of time and energy into yoga can have positive and long-lasting effects for both the ailing and the healthy.

The studies are still new and more investigation must be done before anything can be known for certain, but thus far, a tentative level of agreement has been reached about the potential physiological and psychological benefits that can be derived from yoga.

Why Yoga?

Yoga offers a unique combination of strength building exercises, flexibility enhancing stretches, techniques that develop physical and emotional balance, and a map for the road to self-discovery.

Regular yoga practice imbues a certain serenity that comes from seeing that your right side is better/worse than your left, that even the most strenuous poses eventually end, and that you are not alone in this world.

It is this mixture of physiological and psychological effects that has led medical professionals across the world to seriously consider yoga as a means to heal, prevent, alleviate, or help a whole spectrum of woes.

Mental Health (Stress, Depression, Anxiety, PTSD)

Yoga is one of the most commonly used mind-body interventions recommended by doctors for patients suffering from mental health problems such as depression and anxiety. There are many studies that support the assertion that yoga can help alleviate these symptoms.

One study, from December 2014 [i], asked veterans to participate in a 9-week yoga course. At the end of the course, participants reported significantly decreased levels of anxiety, depression, and suicidal inclinations.

Another study from November 2014 looked at the effects of Hatha yoga on moderately depressed individuals [ii]. Participants reported less fatigue, higher self-esteem and body image, and an overall improvement in quality of life.

There are well-understood, though slightly technical, reasons why yoga is so effective at improving mental health.

The HPA Axis

The practice of yoga down-regulates the hypothalamo pituitary adrenal (HPA) axis — the brain function that triggers a physical or mental reaction in response to stress. The point of the HPA function is to mobilize energy to combat the stressor, enabling the classic ‘Fight or Flight’ response. It does this by releasing cortisol and catecholamine. Repeated triggering of the HPA axis results in a hyper-vigilant state that can lead to obesity, depression, substance abuse, and cardiovascular disease.

Yoga tempers the HPA reaction. Meditation, exercise, and breathing through the nose (breathing through the mouth encourages Flight or Flight syndrome), all help to sooth the stress response system.

Yoga reduces your heart rate, lowers your blood pressure, and eases your breathing. Moreover, with continued practice, yoga will reduce the HPA axis’ threshold for activation — in other words you won’t get stressed out so easily. In this way, yoga eases the struggles caused by stress, depression, anxiety, and PTSD.

Cardiovascular Disease and Hypertension

For similar reasons, yoga can also decrease risks of cardiovascular problems and hypertension. As described above, yoga can help lower your threshold for stress. Moreover, the relaxation and meditation elements of yoga can greatly reduce blood pressure [iii].

In addition to the positive mental effects, the physical elements of yoga can also increase the cardio-respiratory fitness. Physical activity plus breathing exercise works to relax blood vessels and strengthen the heart and lungs.

There is some debate as to whether the exercise involved in yoga practice is uniquely beneficial in preventing cardiovascular disease or if any exercise will do. Either way, an hour of yoga a day can significantly improve the health of someone living a sedentary life. [iv] There is also emerging evidence that yoga can help reduce cholesterol levels.

Chronic Neck and Back Pain

Yoga improves posture and strengthens muscles, thus helping to reduce chronic pain in the neck and back.

A study on chronic back pain by the National Center for Complementary and Integrative Health reports that after 6 months of regular practice, participants had significantly less pain in their lower back and increased mobility.[v]

A similar study on chronic neck pain had participants practice yoga for nine weeks and found that disability and pain were both greatly reduced. Some of the participants who continued to practice yoga after the 9-week period saw up to 12 months of reduced symptoms.[vi]

Other Possible Benefits

The medical benefits of yoga are currently being studied for a wide array of maladies. However, at the time of this writing, the studies have been too small or too inconclusive to be definitive. 


Yoga seems to be a promising therapy to people suffering with asthma.[vii] It can reduce the frequency and severity of the asthma attacks but cannot rid a person of the disease and is not a viable replacement of an inhaler.

Bipolar Disorder

Yoga’s effects on those suffering from bipolar disorder are 50/50. Some participants reported life-changing positive effects including increased energy and focus as well as decreased anxiety.

Other participants said practicing yoga made them feel more depressed and lethargic. In some cases, people even saw increased agitation and manic symptoms.[viii]

Mother & Baby          

Several studies have looked at what happens when children practice yoga. The Practicing Midwife reports that mother and baby yoga sessions benefit both parties. The mother regains abdominal strength and rebuilds the weakened pelvic floor; the baby sees better digestion and strengthened limbs. Yoga is believed to enhance the bond between mother and child.[ix]

Academic Performance of Elementary School Students

Another study involved second and third graders practicing in-class yoga for 10 weeks. The results showed that yoga reduced stress levels in kids and helped them to behave better in class.

The study claims that there could be profound cognitive effects on the child’s development; however, the size of the study and methods of collecting results suggest that much more research needs to be done before yoga can be said to benefit children in this way.[x]


Like all medical assumptions, yoga’s health benefits need to be rigorously evaluated to substantiate medical claims. At the present moment, the scientific health benefits of yoga are subject to fluctuation.

Part of the confusion stems from the wildly varying quality of clinical trials. Many studies have difficulties randomizing controls, acquiring a sufficiently diverse sample size, and ensuring adherence to the practice.

In addition, the length of time yoga is practiced varies from study to study. However, it is possible to see through the ticket and glean a general understanding that yoga can help improve the health and well-being of every day people.

[i] Mindfulness based stress reduction (MBSR) reduces anxiety, depression, and suicidal ideation in veterans, Serpa JG, et al., Med Care, December 2014, abstract.

[ii] An explorative study of metabolic responses to mental stress and yoga practices in yoga practitioners, non-yoga practitioners and individuals with metabolic syndrome, Tyagi A, et al., BMC Complement Altern Med, November 2014, abstract.

[iii] Effect of selected yogic practices in the management of hypertension, Murugesan R, Govindarajalu N, Bera TK. Indian J Physiol Pharmacol. 2000;44:207–10. [PubMed]

[iv] Yoga for the primary prevention of cardiovascular disease, Hartley L, et al., Cochrane Database Syst Rev, May 2014, abstract.

[v] Evaluation of the effectiveness and efficacy of Iyengar yoga therapy on chronic low back pain, Williams K, Abildso C, Steinberg L, et al. ( Spine. 2009; 34 (19): 2066–2076.

[vi] Yoga for chronic neck pain: a 12-month follow-up, Cramer H, et al., Pain Med, April 2013, abstract.

[vii] Impact of yoga on biochemical profile of asthmatics: A randomized controlled study, Agnihotri S, et al., International Journal of Yoga, January 2014, abstract.

[viii] Self-reported benefits and risks of yoga in individuals with bipolar disorder, Uebelacker LA, et al., Journal Psychiatric Practice, September 2014, abstract.

[ix] Mother and baby yoga is good for you, MacDonald C, Practing Midwife, May 2013, abstract.

[x] Effects of a Classroom Based Yoga Intervention on Cortisol and Behavior in Second and Third Grade Students: A Pilot Study, Butzer B, et al., Journal of Evidence Based Complementary Alternative Medicine, 19 November 2014, abstract.