Swimming sciatica has the following three reasons: the first is swimming with sprains or fatigue. If there is no good warm-up, swimming on the buttock muscles or stimulation is relatively large, if the muscle sprain in the local will form inflammatory material exudation, stimulate the sciatic nerve and thus produce sciatic nerve pain; or swimming time is longer, more fatigue, lactic acid buildup and muscle stiffness, adhesion after the exudation will be produced, will also stimulate the sciatic nerve; the second is that the swimming will stimulate the lumbar vertebrae. If the previous lumbar spine is not good, there is a lumbar disc herniation, in the swimming fatigue will be the nucleus pulposus protrudes, stimulate the nerve root and then conduct to the sciatic nerve caused by sciatic nerve pain; the third is the swimming fatigue, cold, especially after the water temperature is cooler, after stimulation to the muscles and the local blood vessels to produce constriction, which reduces the blood supply, resulting in the nerve root ischemia will also cause sciatica. In this case, you need to do a good job of warming up, gradual exercise, avoid exertion, if the pain persists need to go to the examination.