Benefits of Nadi Sodhana Pranayama in the light of science Some books quote scientific research endorsing the benefit of Nadi Sodhana Pranayama. We all know this Pranayama strengthens the respiratory and nervous system. It balances Ida and Pingala currents. Ida (feminine in nature) flows vertically along the left side of the spinal column, while Pingala (masculine in nature) flows parallel to Ida on the right side. Sushumna flows in the middle and represents the experience halfway between the two: the ideal state to be achieved right before beginning the practice of meditation. An imbalance between Ida and Pingala is responsible for a lack of introversion-extroversion harmony in many people. Over-functioning of the Ida channel results in introversion, while predominance of the Pingala leads to a state of extroversion. There are four types of brain waves. During deep sleep, delta waves are pre dominant (a high amplitude brain wave with a frequency of oscillation between 0.5 – 4 hertz), and in a doze, the theta waves (4-8 oscillations per sec.) dominate. The brain waves that interest us are the alpha waves (with a frequency range of 7.5 -12.5 hertz).They are mostly present when the person has closed eyes, is mentally relaxed but still awake and able to experience (generally called meditation state).When the eyes are opened, or the person is distracted in some other way, the alpha waves are weakened, and there is an increase of the faster beta waves (13-40 oscillations per sec.). The amount of alpha waves shows to what degree the brain is in a state of relaxed awareness. EEG measurements prove that alpha waves increase during meditation and the amount of alpha waves in each brain half balance out. Now, the more we practice Nadi Sodhana, the more the alpha waves tend to become equal. Nadi Sodhana creates that perfect balance which is the best condition to enter the meditation state and beneficial to lead a peaceful life.