Patanjali, foremost exponent of Yoga, described pranayama as the gradual unforced cessation of breathing. Pranayama is derived from two Sanskrit words-prana (life) or yama (control). Pranayam or control of prana or life force yields heart beat pulse and mind control. Yoga combines scientific technique of right behavior (Yama-Niyama), proper posture (asana), life force control (pranayama), interiorisation of the mind (pratyahara), concentration (dhyan), developing intuition (dharna) and Samadhi (ultimate realization). Anuloma Viloma pranayama starts with closing the right nostril with the thumb of the right hand, inhaling through the left nostril, holding the breath, followed by exhalation through right nostril while closing the left nostril with the index finger of right hand and then reversing the process. This forms one round of Anuloma Viloma pranayama or Nadishuddi pranayama. Pulse rate and reaction times were recorded before and after twelve cycles of alternate nostril breathing. The pulse rate dropped from 81.5__ampersandsignplusmn;5.3 to 72.9__ampersandsignplusmn;8.7. Reaction times dropped from 0.47__ampersandsignplusmn; 0.15 seconds to 0.38 __ampersandsignplusmn; 0.09 seconds .The changes are statistically significant at p__ampersandsignlt;0.001. The subjects felt joy, peace and were calm. Alternate nostril breathing is a process of continuous, regularity of inhalation, holding of breath and exhalation. It charges the body with an increased supply of oxygen through the lungs, this oxygen __ampersandsignquot;burns__ampersandsignquot; or oxidizes the waste impurities, chiefly carbon, in the venous blood. This process of purification is enhanced by an accompanying large increase in expulsion of waste carbon dioxide from the lungs during exhalation. As a consequence, very little of the tissue remains in the blood as waste material. There is less need for the breath, as the flow to the lungs of blood for purification slows down. The heart and lungs are given extraordinary rest.