Rest days in a fitness program are significant for several reasons. They allow the body to recover and repair from the physiological stress of exercise, which is essential for muscle growth and adaptation. Without adequate rest, the risk of overtraining, fatigue, and injuries increases. Moreover, rest days help replenish glycogen stores and reduce accumulated lactic acid, enabling better performance in subsequent workouts. Including rest days supports long-term adherence to a fitness regimen and promotes overall well-being.