If you’re a passionate yoga practitioner, you’ve probably noticed the ways yoga works-maybe you’re sleeping better or getting fewer colds or just feeling more relaxed and at ease. But if you’ve ever tried telling a newbie how it works, you might find that explanations like “It increases the flow of prana” or “It brings energy up your spine” fall on deaf or skeptical ears.
As it happens, Western science is starting to provide some concrete clues as to how yoga works to improve health, heal aches and pains, and keep sickness at bay. Once you understand them, you’ll have even more motivation to step onto your mat, and you probably won’t feel so tongue-tied the next time someone wants Western proof.
I myself have experienced yoga’s healing power in a very real way. Weeks before a trip to India in 2002 to investigate yoga therapy, I developed numbness and tingling in my right hand. After first considering scary things like a brain tumor and multiple sclerosis, I figured out that the cause of the symptoms was thoracic outlet syndrome, a nerve blockage in my neck and chest.
Despite the uncomfortable symptoms, I realized how useful my condition could be during my trip. While visiting various yoga therapy centers, I would submit myself for evaluation and treatment by the various experts I’d arranged to observe. I could try their suggestions and see what worked for me. While this wasn’t exactly a controlled scientific experiment, I knew that such hands-on learning could teach me things I might not otherwise understand.
My experiment proved illuminating. At the Vivekananda ashram just outside of Bangalore, S Nagarathna, MD, recommended breathing exercises in which I imagined bringing prana (vital energy) into my right upper chest. Other therapy included asana, Pranayama, meditation, chanting, lectures on philosophy, and various kriya (internal cleansing practices). At the Krishnamacharya Yoga Mandiram in Chennai and from AG Mohan and his wife, Indra, who practice just outside of Chennai, I was told to stop practicing Headstand and Shoulderstand in favor of gentle asana coordinated with the breath. In Pune, SV Karandikar, a medical doctor, recommended practices with ropes and belts to put traction on my spine and exercises that taught me to use my shoulder blades to open my upper back.
Thanks to the techniques I learned in India, advice from teachers in the United States, and my own exploration, my chest is more flexible than it was, my posture has improved, and for more than a year, I’ve been free of symptoms. My experience inspired me to pore over the scientific studies I’d collected in India as well as the West to identify and explain how yoga can both prevent disease and help you recover from it. Here is what I found.
Improved flexibility is one of the first and most obvious benefits of yoga. During your first class, you probably won’t be able to touch your toes, never mind do a backbend. But if you stick with it, you’ll notice a gradual loosening, and eventually, seemingly impossible poses will become possible. You’ll also probably notice that aches and pains start to disappear. That’s no coincidence. Tight hips can strain the knee joint due to improper alignment of the thigh and shinbones. Tight hamstrings can lead to a flattening of the lumbar spine, which can cause back pain. And inflexibility in muscles and connective tissue, such as fascia and ligaments, can cause poor posture.
Strong muscles do more than look good. They also protect us from conditions like arthritis and back pain, and help prevent falls in elderly people. And when you build strength through yoga, you balance it with flexibility. If you just went to the gym and lifted weights, you might build strength at the expense of flexibility.
Your head is like a bowling ball-big, round, and heavy. When it’s balanced directly over an erect spine, it takes much less work for your neck and back muscles to support it. Move it several inches forward, however, and you start to strain those muscles. Hold up that forward-leaning bowling ball for eight or 12 hours a day and it’s no wonder you’re tired. And fatigue might not be your only problem. Poor posture can cause back, neck, and other muscle and joint problems. As you slump, your body may compensate by flattening the normal inward curves in your neck and lower back. This can cause pain and degenerative arthritis of the spine.
Each time you practice yoga, you take your joints through their full range of motion. This can help prevent degenerative arthritis or mitigate disability by “squeezing and soaking” areas of cartilage that normally aren’t used. Joint cartilage is like a sponge; it receives fresh nutrients only when its fluid is squeezed out and a new supply can be soaked up. Without proper sustenance, neglected areas of cartilage can eventually wear out, exposing the underlying bone like worn-out brake pads.
Spinal disks-the shock absorbers between the vertebrae that can herniate and compress nerves-crave movement. That’s the only way they get their nutrients. If you’ve got a well-balanced asana practice with plenty of backbends, forward bends, and twists, you’ll help keep your disks supple.
It’s well documented that weight-bearing exercise strengthens bones and helps ward off osteoporosis. Many postures in yoga require that you lift your own weight. And some, like Downward- and Upward-Facing Dog, help strengthen the arm bones, which are particularly vulnerable to osteoporotic fractures. In an unpublished study conducted at California State University, Los Angeles, yoga practice increased bone density in the vertebrae. Yoga’s ability to lower levels of the stress hormone cortisol may help keep calcium in the bones.
Yoga gets your blood flowing. More specifically, the relaxation exercises you learn in yoga can help your circulation, especially in your hands and feet. Yoga also gets more oxygen to your cells, which function better as a result. Twisting poses are thought to wring out venous blood from internal organs and allow oxygenated blood to flow in once the twist is released. Inverted poses, such as Headstand, Handstand, and Shoulderstand, encourage venous blood from the legs and pelvis to flow back to the heart, where it can be pumped to the lungs to be freshly oxygenated. This can help if you have swelling in your legs from heart or kidney problems. Yoga also boosts levels of hemoglobin and red blood cells, which carry oxygen to the tissues. And it thins the blood by making platelets less sticky and by cutting the level of clot-promoting proteins in the blood. This can lead to a decrease in heart attacks and strokes since blood clots are often the cause of these killers.
When you contract and stretch muscles, move organs around, and come in and out of yoga postures, you increase the drainage of lymph (a viscous fluid rich in immune cells). This helps the lymphatic system fight infection, destroy cancerous cells, and dispose of the toxic waste products of cellular functioning.
When you regularly get your heart rate into the aerobic range, you lower your risk of heart attack and can relieve depression. While not all yoga is aerobic, if you do it vigorously or take flow or Ashtanga classes, it can boost your heart rate into the aerobic range. But even yoga exercises that don’t get your heart rate up that high can improve cardiovascular conditioning. Studies have found that yoga practice lowers the resting heart rate, increases endurance, and can improve your maximum uptake of oxygen during exercise-all reflections of improved aerobic conditioning. One study found that subjects who were taught only pranayama could do more exercise with less oxygen.
If you’ve got high blood pressure, you might benefit from yoga. Two studies of people with hypertension, published in the British medical journal The Lancet, compared the effects of Savasana (Corpse Pose) with simply lying on a couch. After three months, Savasana was associated with a 26-point drop in systolic blood pressure (the top number) and a 15-point drop in diastolic blood pressure (the bottom number-and the higher the initial blood pressure, the bigger the drop.
Yoga lowers cortisol levels. If that doesn’t sound like much, consider this. Normally, the adrenal glands secrete cortisol in response to an acute crisis, which temporarily boosts immune function. If your cortisol levels stay high even after the crisis, they can compromise the immune system. Temporary boosts of cortisol help with long-term memory, but chronically high levels undermine memory and may lead to permanent changes in the brain. Additionally, excessive cortisol has been linked with major depression, osteoporosis (it extracts calcium and other minerals from bones and interferes with the laying down of new bone), high blood pressure, and insulin resistance. In rats, high cortisol levels lead to what researchers call “food-seeking behavior” (the kind that drives you to eat when you’re upset, angry, or stressed). The body takes those extra calories and distributes them as fat in the abdomen, contributing to weight gain and the risk of diabetes and heart attack.