BIOCHEMISTRY OF THE BRAIN
After practicing yoga, people often report many beneficial emotional, psychological, behavioral, and biological effects; an increased feeling of well-being is one important example. People experience beneficial changes to both the mind and body because yoga creates change in the neurophysiology of the body. Yoga is effective because it positively alters brain neurochemistry, and it counteracts stress and reduces autonomic arousal of the autonomic nervous system (ANS), including the sympathetic nervous system.
Practicing yoga breathing techniques for 45 minutes for 4 days was helpful in decreasing battered women’s feelings of depression (Franzblau). Other researchers examined ANS functioning and noted that yoga, especially the breath work, increases heart rate variability, decreases blood pressure levels, and decreases respiratory rates. For people with mild to moderate depression, practicing Sudarshan Kriya Yoga (SKY) can improve depressive symptoms. For people with anxiety, practicing Ujjayi breath work as part of SKY can restore a sense of control. Thus, using yoga breath work to counteract the ANS causes the sympathetic and the parasympathetic nervous system to function effectively in response to stress instead of becoming hypo-reactive or hyper-reactive.
Woolery studied the effects of yoga on reducing symptoms of depression in young adults with mild depression. Researchers over a 5-week period examined a 1-hour Iyengar yoga class that focused on physical postures that are supposed to alleviate depression, particularly back bends, vigorous standing poses, and inversions. As expected, the inversions, standing physical postures of Iyengar yoga, as well as those postures that open and lift the chest, were effective in reducing depression scores by almost one-third and significantly improving mood. The backbends, inversions, and standing postures enhanced feelings of mastery and may have countered the slumped body posture associated with depression.
Iyengar yoga practice with inversions, standing postures, and postures that expand the chest were helpful in diminishing mood-related symptoms of depression. The physical postures positively increased mood state experiences of people with depression and also positively reduced other mental health areas such as anxiety. Participants reported increases in positive mood characteristics (confidence and happiness) and energy levels (attentiveness), as well as decreases in negative mood characteristics (frustration and pessimism).
People anecdotally report feeling more at ease after a yoga practice. Researchers attributed these feelings of relaxation to decreased cortisol levels. Cortisol is referred to as the stress hormone and is released during stress to prepare the body for a stress response. A stress response is a physical or cognitive reaction resulting from various disturbing physical, emotional, or chemical factors.
Lower GABA levels have been found in people with depression and anxiety. The physical postures of yoga increase GABA activity levels in the brain, thus decreasing anxious and depressive symptoms. After the participants in the study completed a 1-hour session of yoga postures, Streeter found that GABA levels increased by approximately one-quarter when compared with baseline measurements, regardless of the type of yoga practiced.
Participants who received yoga and meditation training experienced the largest remission rate at 77% and did not develop any new depressive episodes regard- less of using medications or receiving psychotherapy. Meditation in yoga “may be used to let go of thoughts that maintain the depressive affect.
Melatonin is believed to regulate mood and sleep patterns. Researchers found that participants had increased melatonin levels after practicing yoga, particularly meditation. Additionally, people with depression who practiced yoga reported feeling more positive about themselves and their health and also reported sleeping better.