游泳是强身健体的好运动。据资料表明,让实验鼠游泳六周,每周三次,每次一小时,可推迟人工形成高血压的发生。生理科学研究还报道,游泳能使冠状动脉口径增大,并有缓解小动脉痉挛之效。美国医生把游泳列为预防心脏病的最佳运动之一。然而游泳并非对每个人都合适,患有某些疾病的人不宜游泳,如果勉强下水则危害健康甚至生命。因此,游泳前要进行健康检查,在取得体检合格证后,方可下水游 Swimming is a good exercise to keep fit. According to statistics, allowing mice to swim six weeks, three times a week, every hour, can delay the formation of hypertension. Physiological research also reported that swimming can make coronary caliber increases, and ease the effect of arteriole spasm. American doctors list swimming as one of the best exercises to prevent heart disease. However, swimming is not suitable for everyone, people with certain illnesses should not swim, if barely water is hazardous to health and even life. Therefore, before going swimming to conduct a health check, obtain a medical certificate, before the water