We keep changing from one posture to another, because we cannot stay in one posture all the time. Even within one posture, (for example when we are seated) we often have to move our body. Why do we change our posture and move at least some part of the body so frequently? We do so to ease the discomfort and physical pain that arises in the body . If we stay motionless for a very short length of time we can experience much discomfort and physical pain arising in various parts of the body. This is a result of the changing nature in the balance of the elements. When they are in imbalance there is pain and even sickness. When balance is brought about there is health and comfort. However, owing to the changing nature, both balance and imbalance are impermanent.