Arm cramps may be caused by cold or poor lifestyle and other physiological factors, may also be due to myofasciitis, nerve compression, metabolic disorders, vascular disease and other disease factors lead to, should consult a doctor to find out the cause. 1. Physiological factors: when cold or bad posture compression of the arm, will cause arm muscle spasms, resulting in the occurrence of cramps, through rest and warmth, can be relieved by themselves. 2. Myofasciitis: due to the richness of the muscle fascia of the arm, if engaged in long-term heavy labor, will be repeatedly stimulated and pulled, the muscles will be involuntary contraction and trembling, part of the often accompanied by local pain. 3. Nerve compression: With nerve root cervical spondylosis, due to the compression of the nerve root, it will cause nerve conduction disorders, which will also cause cramps in the forearm. 4. Metabolic disorders: when there is low blood calcium, low blood potassium, diabetes and other diseases, resulting in motor nerve fiber lesions, can also appear forearm cramps. 5. Vascular lesions: when aneurysm or vasculitis occurs in the blood vessels of the arm, due to the obstacle of blood circulation, it can also cause arm cramps. To sum up, when arm cramps occur, after eliminating physiological factors, you should consult a doctor in time to find out the cause and follow the doctor’s instructions for standardized treatment.