Iyengar Yoga practice involves yogic discipline. This hot yoga energy is often associated with the element of fire. B.K.S. Iyengar’s translation II.43 in Light on the Yoga Sutras of Patanjali “Self-displine (tapas) burns away impurities and kindles the sparks of divinity.” You may feel heat on the soles your feet when you practice standing yoga poses. Your arms may feel full of fire if you holding them about to the side for prolonged period of time. Be alert, there is a fine line between doing a pose that may cause pain and doing a yoga asana while practicing tapas. Discrimination and self-awareness within the practitioner are needed for progress.