My head is a pretty chaotic place. I know I am not alone in this. Patanjali, compiler of the 'Yoga Sutras' defines Yoga in the four words 'Yogas chitta vritti nirodhah'.
Chitta is 'Mind Stuff'. It is the mass of connections forming and breaking in our heads. It is the conversations we have with ourselves. It is the conversations we have with Avatars of people we know. Second guessing. Third guessing. Going down the garden paths of what might happen. Going down the garden paths of what could have happened. It is our hopes. Our dreams. Chitta is constrained only by our imagination and the world we are able to create, and it is a factory for emotional responses. It is a 'veil' through which we see the world.
Vritti is the 'Waves'. Our thoughts come and go. They are affected by our emotions, our health, the time of day, who we are with, whether we have eaten, how fit we are, and what we are doing. The same thing can cause a different reaction when repeated, because things are never really repeated. These waves can take us up and down. They can stop us in our tracks when they are flowing in the opposite direction of where we want to go. They can build momentum when we catch them.
Nirodhah is 'Tranquility'. Yoga effectively becomes the practice of freeing ourselves from the control of thoughts. Stilling the waves. The anxiety or unproductive difficulties we face are often embedded in quite simple things. Proper exercise, breathing, diet, relaxation and ways of processing thoughts can give a sense of calm to handle whatever life can throw at you.
Yoga is stilling the waves of the mind