Shimizu rode two junior world records in the 500 metres and sprint combination in 1997. She won at the 2001 Asian Speed Skating Championships the silver medal in the 500 metres event and the bronze medal in the 1000 metres event. She participated three times at the World Sprint Speed Skating Championships for Women: in 1997 (finishing 16th overall), 1999 (finishing 23rd) and in 2003 (finishing 19th). She participated at the European Speed Skating Championships for Women in 1981. At the 1999 World Single Distance Speed Skating Championships she competed in the 1500 metres event (23rd), She also competed at other international competitions, including at ISU Speed Skating World Cups and 1996 Asian Winter Games and 2003 Asian Winter Games.