Magnesium is utilized to facilitate the movement of messages and nerve signals throughout the body. It also assists in the relaxation of the mind and body and calming of the nervous system, an important function in those suffering from hyperactivity disorders. Children with hyperactivity disorder tend to behave calmly if their bodies are calm and relaxed. When the levels are optimal, thinking is clear and concentration is better. When magnesium levels are low, a person may experience muscle twitches and spasms.