Reducing stress levels can greatly improve health and quality of life—and yoga is arguably the best overall system for stress reduction ever invented.
Just about any system of yoga can help reduce stress levels, and this is undoubtedly a major reason for the current surge in yoga's popularity: Sky-high stress is endemic in our society. Not only can stress make life less enjoyable and contribute to such bothersome symptoms as headaches, insomnia, and back pain, but it's linked to many of society's killers, including osteoporosis and heart attacks. Even conditions that aren't caused by stress can prove much more bothersome during stressful times.
Stress and Vata Derangement
High levels of stress are often correlated with what Ayurvedic doctors call vata derangement, when the "air element," associated with movement and instability, becomes increased. When vata levels are high, the affected person usually has a rajasic state of mind, flitting from one thought to the next without being able to focus. Typical symptoms of a vata imbalance include impatience, anxiety, insomnia, and constipation, all of which are commonly linked to stress.
While vigorous asana practices can help burn off nervous energy, stressed-out students need to watch the tendency to overdo. Strenuous workouts may leave them feeling temporarily more sattvic but, if not balanced by sufficient winding-down and relaxation, they can lead to increased vata derangement and, ultimately, a quick rebound of symptoms. Also be careful with strong breathing practices such as Kapalabhati and Bhastrika, which can increase vata. Specific yoga practices to lessen excessive vata include squatting, as in Malasana (Garland Pose), standing poses in which an emphasis is placed on grounding well through the legs, and a regular practice of inversions such as Sarvangasana (Shoulderstand).
Ayurveda would also suggest that people whose vata is high should try to stick to a regular schedule of sleep and meals and, whenever possible, eat warm, nutritious, sattvic foods. Sweet, sour, and salty tastes are considered beneficial for reducing vata. Crunchy foods such as corn chips, granola, or raw broccoli are said to increase vata levels. Caffeine, nicotine, and other stimulants may also make matters worse.
See alsoRecipe: Vata Frittata
Breathing and Stress
One of the ancient yogis' most profound insights was the link between breathing patterns and state of mind. Shallow, rapid breaths—the way many people breathe most of the time—can, from a yogic perspective, be both a cause and a result of stress. Think of how you breathe if you are startled, with a quick inhalation primarily to the upper lungs. Physiologically, habitual rapid chest-breathing is a bit like getting startled thousands of times per day.
The yogic remedy is to slow the breath down. One way to do this is to breathe through the nose. The greater resistance to air flow in the nasal passages compared to the mouth results in a naturally slower respiratory rate, and nasal breathing is also beneficial because it warms and filters incoming air. Ujjayi breathing, in which the vocal cords are narrowed, similarly increases the resistance to air flow and allows the breathing to slow. The sound generated in Ujjayi can also be used as a meditative focus, further contributing to a calmer mind.
It's also calming to breathe more deeply than most people usually do. Abdominal breathing, in which the diaphragm is used to maximum advantage on the inhalation and the abdominal muscles help squeeze air out on the exhalation, results in larger breath volume. It turns out that slower, deeper breaths are much more efficient in bringing oxygen into the body while not exhaling more carbon dioxide (CO2) than is desirable. Rapid, shallow breaths, in contrast, tend to deplete CO2 levels, which has a number of negative effects, including promoting mental agitation.
A simple technique, which can provide almost instant stress reduction, is to lengthen the exhalation relative to the inhalation. Doing so increases the tone in the parasympathetic nervous system, which increases relaxation and decreases the sympathetic nervous system's fight-or-flight response. Have your students work toward a 1:2 ratio of inhalation to exhalation, but under no circumstances should they feel any breath hunger (which sets off the stress response) when doing the practice. Once students master this technique, they can use it whenever stress flares up—in the office, while driving, in an airplane—without anyone around them necessarily being able to detect it.
Pratyahara, the turning of the senses inward, is the fifth of Patanjali's eight-limbed path of yoga and can be an important tool for stress reduction. I believe one reason so many people in the modern world are stressed out is because of the visual and auditory stimulation constantly bombarding us. Even if you don't realize it, ringing phones, blaring TVs, and traffic noises tend to activate the sympathetic nervous system. Many people add to their sensory overload by reflexively turning on the TV or radio while they eat or sit down to relax. You might suggest to students that, at least sometimes, they try to eat or sit in silence and see if it doesn't result in a sense of greater relaxation. It's not a bad idea to turn the phone off sometimes as well.
Consciously going inward on a regular basis can be a partial antidote to regular assault on the senses, both calming the nervous system and making you more resistant to future assaults. Practices such as Savasana (Corpse Pose), Pranayama, and meditation cultivate introspection. Regular practitioners can usually notice when external or internal stressors are mounting, portending a serious flare of stress. Detecting the spark before the fire, as Buddhists put it, can help you institute breathing practices or take other action before stress spirals out of control.
Yoga's ability to reduce stress deepens with regular practice. Tell your students that a little bit every day is great preventive medicine for stress, and it will make the use of breathing practices, deep relaxation, and other yogic tools more effective. If they protest that they are too busy to practice regularly, tell them that's precisely why they need to find a way to do it.