She was born to a bossa nova bassist and a primary school teacher. When Amorim was 3 years old, her sister Paula who had asthma was recommended by a doctor to take up swimming to help with her asthma. Amorim started swimming by going along with Paula to the swimming classes. At 5 years old, Amorim swam across Guanabara Bay in Rio. She represented her native country at the 1988 Summer Olympics in Seoul, South Korea. She retired from swimming in 1991.[1]
She was at the 1987 Pan American Games, in Indianapolis, where she finished 4th in the 4×200-metre freestyle, and 5th in the 200-metre, 400-metre and 800-metre freestyle.[6]
At the 1988 Summer Olympics in Seoul, Amorim finished 11th in the 4×100-metre medley, 21st in the 800-metre freestyle, 24th in the 400-metre freestyle, and 25th in the 200-metre freestyle.[3]
Amorim won both the 400 m and 800 m freestyle gold medals at the 1989 Maccabiah Games in Israel.[7]
Amorim broke the South American record of the 400-metre freestyle at the 1988 Summer Olympics, with a time of 4:19.64. The record lasted 10 years, and was only broken in 1998 by Nayara Ribeiro.[8]
Amorim also broke several South American records in the 800-metre free, the first in 1985 and the last in 1988 Seoul: 8:51.95. Her record lasted until 1999, when Ana Muniz did 8:48.53. She is the person who most often hit the Brazilian record of 800-metre freestyle, six times.[9]
Amorim is married to Fernando Sihman and has four children.[1]
On December 3, 2012, in spite of running for Flamengo's presidency re-election, she was defeated by Eduardo Bandeira de Mello.