It has become common knowledge that yoga is good for you. Currently yoga is being used as a therapy for cancer, infertility, lung disease, multiple sclerosis, Parkinson’s disease, insomnia, high blood pressure, and joint pain. Yet there is very little awareness and understanding on exactly how yoga heals, even in the yoga and medical communities. The key is to understand the relationships between stress, yoga and disease.
Medical research estimates as much as 90 percent of illness and disease is stress related. A few of the many diseases and conditions that have been linked to an overactive stress response include: cardio-vascular disease, depression, anxiety, obsessive-compulsive disorder, some types of diabetes mellitus, some autoimmune diseases, colitis, irritable bowel syndrome, reproductive problems, and suppression of the immune system.
What we feel as stress, is the product of the sympathetic nervous system or the “fight or flight” response: an almost instantaneous surge in heart rate, cardiac output, blood pressure, sweating, shallow breathing, and metabolism, combined with a tensing of muscles. Internally, the “fight or flight” response shuts down digestion and elimination and reduces blood flow to the internal organs. Short term, this stress reaction is a good thing. The “fight or flight” response prepares us to respond to any environmental threat by fighting against it or fleeing from it. But long term, continuous exposure to stress is harmful, placing excess wear and tear on the body’s systems and severely limiting the body’s natural maintenance and healing abilities.
Chronic stress can lead to continuously high levels of cortisol. This hormone at normal levels helps to maintain an active, healthy body (including regulation of metabolism and blood pressure). But excessive amounts of cortisol can suppress the immune system and cause sleep disturbances, loss of sex drive and loss of appetite. High levels of cortisol can also increase your heart rate, blood pressure and your cholesterol and triglyceride levels (risk factors for both heart attacks and strokes). The byproducts of cortisol act as sedatives, which can lead to changes in mood, especially to feelings of depression.
Fortunately, the body has a natural counterbalance to the “fight or flight” response, called the parasympathetic nervous system or the “relaxation response.” The parasympathetic nervous system becomes activated when the threat or stressor has passed or ended, but it can also be consciously activated by deepening the breath and by relaxing the skeletal muscles.
When activated, the parasympathetic nervous system lowers blood pressure, heart rate and respiration (the pace of the breath). Digestion and elimination are allowed to be stimulated, and blood is free to travel to the digestive, reproductive, glandular, and immune systems — systems necessary for the promotion of long-term health. The “relaxation response” is also known as the “rest and renew” stage, when the body has the time and resources to heal the body and to respond to illness. Obviously, by increasing the frequency, time and depth of the “relaxation response” we not only allow our body to recover from illness and disease, but we also practice preventive medicine by allowing the body to perform all of its essential maintenance tasks.
Yoga’s emphasis on long, deep breathing and conscious relaxation activates the parasympathetic nervous system and promotes its “rest and renew” functions. In fact, a recent study has shown yoga to decrease the level of the stress hormone cortisol in the blood. The meditative practices of yoga help to reduce the reactiveness of the mind to stressors and to lessen the intensity of the “fight or flight” response. Yoga also teaches us to see potential stressors as challenges rather than threats, enabling one to avoid the stress response entirely.
Not only does yoga’s ability to activate the parasympathetic nervous system reduce stress and allow the body to heal itself, but the practice of yoga also improves the body’s inherent healing abilities. The inverting, twisting and compressing that occurs in yoga postures enhances the circulation of blood and body fluids. This increase in circulation not only improves the body’s ability to deliver the materials needed to allow healing to take place, but also activates the lymphatic system to maintain normal functioning of the immune system and inflammation response. Yoga poses also improve muscle strength, flexibility and range of motion, all very important for the healing and prevention of musculoskeletal diseases such as arthritis and osteoporosis. Yoga’s emphasis on deep breathing combined with backbends improves lung capacity and function. Practicing yoga also encourages one to lead a healthier lifestyle, through developing the self-awareness and discipline required for positive behavior modification.
While yoga possesses such a strong support to the body’s healing mechanisms, it is important to view yoga as an adjunct or complementary therapy, and not relied upon as the only therapy for healing disease.