As stated in "effort & surrender", Iyengar Yoga is a very challenging physical and mental discipline. Consequently, physical and mental discomfort is often experienced by beginning students because of lack of flexibility, strength, stamina and mental focus.

As one puts forth effort to perform postures that the body and mind are not used to, many resistances are felt. These resistances commonly manifest in the body as discomfort. A feeling of discomfort in a general area of the body while performing a posture with good alignment is not a problem. The discomfort will cease when one comes out of the pose. Discomfort is a relative feeling. A beginning student performing the same pose with the same good alignment will generally feel much more discomfort than the advanced student.

Discomfort does not indicate injury. The feeling of discomfort will often soften and lessen if one does not mentally fight the feeling.

Pain in a yoga pose, on the other hand, usually indicates a physical misalignment or improper muscular action. A specific burning or intense, localized sensation in the body is referred to as pain. If one feels pain in a muscle or joint, one should immediately change or modify the posture until the pain is relieved. One should closely observe the postural misalignment that caused the pain, and correct the pose accordingly. Pain indicates that injury will probably occur if the misalignment is maintained.