Yoga is an ancient Indian way of life which includes changes in mental attitude, diet and practice of certain techniques such as Yoga Asanas (postures), breathing practices (Pranayama) and meditation to attain the highest level of consciousness. Since yoga aims at perfection of body and mind, it is natural to ask whether the progress towards perfection is reflected in objective reproducible changes in physiological variables. The amazing claims made by some yogis such as their ability to stay underground for long periods or to stop the heartbeat voluntarily, have posed a challenge to scientists to either confirm or refute these claims. Further, the claims regarding wide ranging therapeutic benefits of yoga have prompted scientists to examine whether there is any physiological basis for such claims.
Key words: Yoga, Mana, Atma, Pranayama