Since the distance between the Zeeman sub-levels is a function of the magnetic field, this effect can be used to measure the magnetic field, e.g. that of the Sun and other stars or in laboratory plasmas.
Charley horse: Slang for a cramp in a muscle in the leg, usually caused by a strain or injury. A charley horse can last anywhere from a few seconds to over a quarter of an hour. It is not uncommon for one to recur before it finally resolves.
Charlie horses in stomach can occur at any time and at any age however it is more common in adults. The pain due to Charlie horses is so severe that the patient can awake in middle of the night. The condition is more prevalent in athletes, patients suffering from intestinal and stomach problems, obese individuals etc.