After setting a European record in the 400 m medley event in 1961 she shifted to marathon swimming and was ranked world No.

Together with her elder sister[5] Lenie she trained under the famous Dutch coach Jan Stender, and both became record-breaking swimmers.

This way, she became a professional swimmer and earned prize money for the races she won.

[10][11] They have a daughter and a son, water polo player Robert van Berkel.

She remained competitive swimmer through the 1980s–2000s, winning national titles in senior categories in 1988–2001, 2005, 2007 and 2009 (3–4 km freestyle).