Sudden hand cramps are mainly in the muscles of the forearm, under the stimulation of undesirable factors leading to dysfunction, acute uncontrolled and violent spasms of muscles and fibers, resulting in cramps in the hand, with the following common causes: a. Due to local ischemia and hypoxia in the muscles after a long period of strenuous exercise, coupled with the stimulation of a large accumulation of metabolites, such as lactic acid, leading to muscle dysfunction in the forearm and violent spasm leading to cramps. Second, it can be seen in a large amount of fluid loss, such as sweating or diarrhea in hot weather, resulting in electrolyte disorders in the body, and electrolyte disorders will affect the function of nerves and muscles, resulting in muscle spasms, leading to sudden cramps in the hands. Third, it can be seen in acute injury, due to injury stimulation muscle, resulting in muscle function abnormalities, also to appear sudden hand cramps. 4. Acute cold or bad physical and chemical factors stimulation, resulting in the local blood circulation of the muscle is affected, poor blood circulation will also appear ischemia, hypoxia, resulting in abnormal muscle function, resulting in sudden cramps of the hand.