The Yoga Effect

CHAPTER 1

THE JOURNEY TOWARD BECOMING WHOLE AGAIN

Mahatma Gandhi once said, “The future depends on what we do in the present.”¹ If you are reading these words in the midst of a struggle with depression or anxiety, you have taken a brave and important step in this present moment, one that I earnestly believe will illuminate a path toward a more positive future.

What is this great act of courage? It’s nothing more complicated than the decision you made to pick up this book.

Now, let’s not get ahead of ourselves. As much as I wish it were, this book isn’t a magic wand that can permanently vaporize the weight of depression or tamp down the spiral of anxiety. No single book can do that, nor can any one therapy session, prescription, guided meditation, or yoga pose.

Why, then, is opening this book a healing act? How can it help you along the road back to wholeness from the stuck, uncomfortable place of depression and anxiety?

I believe the answer to that question lies in those words spoken by Gandhi. What stands out to me most in his statement is how vast, complex, and multifaceted those two categories of time—“the present” and “the future”—actually are. No single choice, no single action gets us from here to there. Instead, each of the myriad decisions we make in the here and now shapes the future we hope to see. It is my hope and intention that this book might become one healing choice among many that can set you on a path toward a better tomorrow.

All human beings struggle with difficult emotions at some point in their lives, whether they have a mental health diagnosis or not. And though so-called negative emotions like fear, sadness, and anger are often dismissed and discouraged in modern culture, those emotions serve a purpose in the big picture of our inner lives.

But those feelings aren’t serving their purpose if they feel unmanageable to you on a regular basis. According to the National Institutes of Health, 21 percent of American adults—that’s more than one in five—experience a mood disorder at some point in their lives.² Your journey toward wholeness starts with an honest appraisal of what most challenges you here, now, in the present moment.

Which is where yoga comes in.

YOGA AS A TOOL OF THE MIND

Yoga, like any system of thought, belief, and action, has a central set of teachings that define its purpose and perspective. One of these writings, compiled around the year 400 CE, is called The Yoga Sutras of Patañjali, and it describes the what, how, and why of the practice we understand today as yoga.

Let’s consider this collection by the numbers. There are 196 sutras. Three have to do with physical poses; five more describe breath work and its effects.³ The remaining 188 teachings focus on a single purpose—how to understand the mind and the human experience of consciousness, with a goal of becoming free from suffering.⁴

How remarkable that virtually the entire foundation of yoga is built around the philosophy of a disciplined mind, one that is organized, focused, present, reflective, discerning, and tranquil.

Given how fundamentally the practice is rooted in the mind-body relationship, it’s no wonder that for decades, scientists have been investigating the connection between yoga and mental health. Literally hundreds of studies have examined yoga practice and inquired about its effectiveness, especially those “how” and “why” questions Patañjali considered in the sutras.

As you keep reading, let each passing page anchor Gandhi’s suggestion more deeply in your mind. None of us can know or control the future, but by choosing to invest our time in healing actions again and again, here and now, in the present moment, we can take steady steps toward wellness, toward wholeness—toward our fully authentic selves.

WHAT MAKES THIS BOOK “EVIDENCE-BASED”

Throughout my thirty years teaching yoga, I have seen it change the lives of my students in profound and permanent ways. I have seen pain resolve into peace. I have seen inflexibility evolve into elasticity. I have seen people open their eyes to their own bodies, seeing themselves in new, transformative ways. I have taught college students; expectant mothers; those living with chronic fatigue syndrome, scoliosis, and multiple sclerosis; and people struggling with chronic challenges ranging from breathing disorders to weight management to pain to depression and anxiety.

When I met Dr. Chris Streeter, an associate professor of psychiatry and neurology at Boston University School of Medicine in 2006, I got an opportunity to dive more deeply into what I already understood about how profoundly yoga practice affects people, however life has challenged them.

Dr. Streeter invited me to work with her on a series of scientific studies about how yoga impacts mental health. Over the years since, I have learned more about those “how” and “why” insights that have captivated philosophers and scientists alike over the centuries.

When I partnered with Dr. Streeter, she had already completed some research on this topic, including a promising pilot study that found experienced yoga practitioners had an increase in a brain chemical called gamma aminobutyric acid (if attempting to pronounce that is making your heart pound, fear not: it is also referred to with the simple acronym GABA) after just an hour of practicing yoga postures.⁵ GABA is a neurotransmitter, a chemical messenger that delivers information from one area of your brain to another. It’s known as an “inhibitory neurotransmitter,” meaning that when GABA attaches to receptors in the brain, it makes brain cells, called neurons, less likely to release other chemicals into your system or take another action.⁶ If you have taken or considered antidepressant medications, you might note that a popular class of drugs is called selective serotonin reuptake inhibitors. SSRIs also work in an inhibitory way, slowing the rate at which serotonin—another neurotransmitter we need to manage our moods—is reabsorbed into the brain.⁷

GABA has been the focus of Dr. Streeter’s subsequent research, as she’s investigated how GABA affects mental health and how yoga impacts GABA levels. Over the course of three separate studies, my role was to lead a team of yoga teachers, under the mentorship of the noted Iyengar yoga teacher Patricia Walden, in creating a manual of the precise sequences of yoga poses and breath work that participants would undertake during their twelve weeks of yoga practice.

As you will soon learn, these studies produced very positive results, making groundbreaking observations about the association between yoga practice and improved mental health. The book you are holding in your hands is based on the practices our study participants did on their journeys toward wellness.

YOGA SCIENCE: THE BIGGER PICTURE

Scientists have been interested in yoga for more than a century.¹⁰ But it’s only since the 1970s that more funding and widespread interest in the West has led to a substantial body of research exploring the science of how yoga actually works.

The question of whether and how yoga affects emotional well-being has been a much-studied topic; the studies discussed in this book were funded by the National Institutes of Health’s National Center for Complementary and Integrative Health and have been published in the peer-reviewed scientific publication the Journal of Alternative and Complementary Medicine. If you are reading this book because you are suffering from depression, anxiety, or both, know that a significant number of the hundreds of studies on yoga and mental health have yielded promising or positive results.

Good science is rooted in inquisitiveness, the willingness to pursue a question knowing its answer will lead to further inquiries to explore. Researchers have examined the connection between yoga and mental health around a number of questions, including the effects of different breathing speeds on stress, anxiety, and depression, the effects of yoga on post-traumatic stress disorder (PTSD), how yoga affects younger and older practitioners’ mental health differently, and so much more.¹¹ New research is continuing to emerge even as I write these words.

THE BRAIN SCIENCE BEHIND OUR RESEARCH

So what has research contributed to the broader body of knowledge on yoga and mental health? In a nutshell… a lot. Its contribution zooms in from the broad concept of “the mind,” which so occupied Patañjali, and instead focuses on arguably the most complex organ in the human body—the brain.

Dr. Streeter’s research began with the observation that depression, anxiety, and epilepsy were all treated with drugs that increased the activity of what scientists call “the GABA system”—and the simultaneous observation that symptoms decreased in all three disorders during a yoga intervention. She wondered whether a yoga session might be associated with increased GABA levels and improved mood in healthy subjects. The premise was that low GABA levels were associated with lower mood and heightened anxiety. Some studies refer to GABA as a “natural antidepressant” because the more of it you have, the less depressive or anxious your moods are likely to be.¹²

To delve more deeply into the important role of GABA in mental health, Dr. Streeter set out to study this question: how, if at all, is the practice of yoga postures associated with changes in GABA levels?

Study 1: For Emotional Health, How Does Yoga Compare with Walking?

Our first study together was published in 2010.¹³ Thirty-four study participants were divided into two groups—nineteen completed a twelve-week program of twice-weekly yoga classes, while fifteen others did a twelve-week walking program. None of the participants was experienced in yoga, and none had a mental health diagnosis such as Major Depressive Disorder or Generalized Anxiety Disorder.

Dr. Streeter and her scientific team measured the participants’ moods using two techniques. One was a pair of self-reported tests: the Exercise-Induced Feeling Inventory (EFI) and the State-Trait Anxiety Inventory (STAI).¹⁴ The other was a brain scan called magnetic resonance spectroscopy, or MR spectroscopy (MRS). This scan is conducted on the same machine as an MRI, but it supplements the information provided by MRI scans with an additional measure of chemical levels in particular regions of the brain. Our MRS scans were designed to measure GABA levels in the thalamus, the region of the brain that has a high concentration of GABA and is connected to the circuits that modulate emotions and thoughts throughout the central nervous system.¹⁵

Both the walkers and the yoga practitioners completed the self-reported tests four times throughout the twelve weeks. They underwent the scans three times—once before the first session of either yoga or walking, and twice more after the twelve-week intervention was complete. Both those scans were done on the same day—once before and once after a final session of either yoga or walking.

The results of the study were extremely positive. Both groups experienced improvements in mood, but the yoga group had a greater boost—and only the yoga group showed an increase in GABA levels. This suggested that mood improvement is associated with increased GABA levels—and that yoga practice is associated with this positive correlation.¹⁶

Armed with this solid finding, but not yet able to assert proof that changes in GABA levels improve mood, Dr. Streeter decided it was time to ask more questions.

Study 2: Is More Better When It Comes to Yoga?