Yoga works at multiple levels — physiological, emotional, mental, intellectual and spiritual. Yoga is subliminal. With it you control your own well-being.
Through yoga you can go back to that pristine, uncorrupted state — one of sheer joy, where matters are not so grave and from which you gain enormous physical and mental rejuvenation.
Physiologically yoga can significantly enhance your immune systems, your muscular systems and the functioning of various organs and internal systems of the body. A major proportion of ailments are psychosomatic and Yoga helps you address them at the root cause and not through symptomatic relief.
Mentally with yoga you can find an equally boundless ability to dissolve one's quirks and biases, the ability to handle life’s stresses and gain enormous mental strength and fortitude.
Simply put one's "nature" is a very malleable and evolutionary thing whose possibilities are limitless, but whose realization is often limited.
Yoga can help you develop intellectually in many ways, e.g. being more discerning and discriminatory. Simple things such as the incongruity of "My God is God, your God is not" become more readily (and harmoniously) apparent.
With Yoga one's health - health defined as the well-being of the body, mind and soul - is largely in one's own hands.