One should rub the body with the water (sweat) produced by the effort. By this, firmness and lightness of the body are developed.

This verse offers an important practical instruction: the sweat generated during prāṇāyāma practice should not be wiped away with a towel but rubbed back into the skin (gātramardanam). This practice is considered beneficial for the body’s health.

The two benefits mentioned are dṛḍhatā (firmness, strength) and laghutā (lightness). These may seem like opposing qualities, but in the yogic context they represent the ideal balance: a body that is strong but not heavy, capable of maintaining āsanas for prolonged periods without fatigue.

From a modern perspective, sweat contains minerals and electrolytes that can be reabsorbed through the skin. Āyurveda texts also mention that sweat produced during spiritual practices has different qualities from ordinary sweat, containing subtle impurities that are being eliminated from the system.