Body cramps may be caused by calcium deficiency, fatigue, cold, or vascular disease. Body cramps may be caused by calcium deficiency, mostly occurring during strenuous exercise or at night, lasting for about half an hour and can be relieved by itself, recurring, and can be clarified by calcium ionization. When the body’s anaerobic exercise increases due to strenuous exercise or tiring work, lactic acid builds up and body cramps appear, which can be relieved by resting, drinking more water and massage. Body cramps occur when the skeletal muscles contract after catching a cold, and can be relieved by keeping warm. If there is a vein thrombosis in the leg with slow blood flow and insufficient blood supply to the tissues, body cramps can also occur, which can be clarified by ultrasound. When the above symptoms occur, you need to go to the hospital for examination and clarification.