Yoga’s roots stretch back to ancient India, first being documented in the middle of the 1^st millennium BCE. It is derived from the Sanskrit root yuj, which roughly translates to ‘union’ or ‘yoking’. This is thought by many to refer to a union between the body and mind—others would argue between oneself and a deity.

Though an important religious practice to many, historically and presently, yoga is not strictly a holy ritual. It combines physical and mental practices to exercise control over both body and mind, with the aim of fostering higher levels of awareness in everyday life. This is considered spiritual by some and not by others.

In this article, we cover yoga’s origins and delve into what modern research suggests about this ancient practice.

The history of yoga

Yoga is thought to have been conceived of over 2500 years ago in northern India.

The term itself has an array of meanings due to its global popularity and use in various religious contexts over millennia. It has been a cornerstone of Indian culture and religion, being a crucial component of many branches of Buddhism, Hinduism, and Jainism.

The Indus Valley Civilisation, a Bronze Age society who inhabited areas of South Asia from 3300 BCE to 1300 BCE, depicted figures performing what look like yogic poses in their artwork. However, whether these are yogis or not is widely debated, as their system of writing has not been sufficiently deciphered to validate this claim.

Yoga is mentioned extensively in literature from the Vedic period (1500–500 BCE). The Vedas are the oldest scriptures of Hinduism. One of the four, the Rigveda, features the term yoga frequently. Though, its meaning differs throughout and many elements now associated with yoga are not present.

Over the millennia since it was first introduced, yoga has evolved to suit many different people and purposes. In the modern era, yoga is a popular activity practiced worldwide, having been popularised in the Western world over the last two centuries or so. In the UK alone around 300,000 to 460,000 people go to yoga classes each week.

What does yoga involve?

There are many different schools of yoga, which vary in difficulty, method, and intention.

Generally, yoga practitioners perform a series of physical poses (āsanas) designed to strengthen the body and improve balance and flexibility. During these sequences, they aim to still the mind through fixed concentration (dharana) and deep breathing (pranayama).

What most systems seem to have in common is the aim to unite the mind and body.

What is the mind–body connection?

Long before we understood the complexities of the brain, philosophers speculated on the relationship between body and mind. Buddha, Plato, Descartes, Kant, and many more had differing and speculative theories on the dynamics of this connection.

Though their work is mostly conceptual, recent research shows us that this is not just a philosophical abstraction. The mind and body are inextricably linked: problems with our physical health can lead to emotional disturbances, and likewise poor mental health can lead to physical symptoms. Think of the knot we feel in our stomachs when we experience anxiety, for example. Or the malaise that accompanies seasonal flu.

Stress has particularly been shown to have a huge influence on many aspects of our physical health. Two of our recent articles cover the impact of stress on the immune system and how to lower stress using mindfulness.

How does yoga improve mental health?

Burnout—physical and mental exhaustion—is an increasingly common problem in the modern day. With the rise of mental health issues worldwide, despite the advances in pharmaceutical treatments, researchers are starting to look into interventions such as meditation and yoga to address these issues more effectively.

The blend of physical and mental exertion in yoga appears to have many positive effects on quality of life. It has been shown to be an effective intervention to treat depression, anxiety, and stress. It can also improve sleep as well as emotional regulation.

MDPI research has found that yoga can improve workplace resilience and psycho-physical wellbeing. Teachers reported increased emotional and physical awareness, as well as fewer symptoms of professional burnout.

In another MDPI study, researchers conducted a literature review on yoga interventions for neurotypical and neurodiverse youth populations. They found that yoga relieved symptoms of depression and improved self-esteem, subjective and psychological well-being, attention and academic performance in neurotypical participants. Less research was found for neurodiverse populations. But, the review yielded strong evidence for improved self-concept, subjective well-being, executive function and academic performance for such individuals.

How does yoga change the brain?

Many studies on yoga rely on self-report measures to study its efficacy as a therapeutic intervention. Alongside this, many researchers have reported changes in brain structure and function following yoga interventions.

Yoga affects the functional connectivity of the default mode network (which is important in emotional regulation and empathy), the activity of the dorsolateral prefrontal cortex while engaged in cognitive tasks, and the structure of the hippocampus and prefrontal cortex. These are all associated with age-related decline and neurogenerative disorders, so yoga may help to prevent or slow these issues.

Additionally, MDPI researchers conducted a meta-analysis to assess the impact mind–body exercise has on the brain. They found that such interventions altered the brain structure, neural activity, and functional connectivity of the participants.

Future research

The inherent problem in much yoga research is that sample sizes are generally small. Therefore, findings should be interpreted with caution and not rashly applied to the general population.

However, it is clear that yoga can have many positive effects on physical and mental wellbeing. As more research is carried out and meta-analyses conducted, we will continue to learn more about the extent and mechanisms by which yoga impacts our health.

If you want to find out more about the benefits of yoga, IJERPH publishes much cutting-edge research on its therapeutic potential. This includes a Special Issue entitled Yoga and Health.