The practice of Kriyayoga is given by Patanjali in the second chapter for students of moderate means. This practical approach helps us transcend our volatile nature and enter the present moment through practice.
In ‘Light on the Yoga Sutras of Patanjali’, Iyengar says:
The conjunction of effort, concentration, and balance in asana forces us to live intensely in the present moment, a rare experience in modern life. This actuality, or being in the present, has both a strengthening and cleansing effect: physically in the rejection of disease, mentally by ridding our minds of stagnated thoughts or prejudices; and, on a very high level where perception and action become one, by teaching us instantaneous correct action; that is to say, action which does not produce reaction. On that level we may also expunge the residual effects of past actions.BKS Iyengar